close

Вход

Забыли?

вход по аккаунту

?

Metal Vinylidenes and Allenylidenes in Catalysis Applications in Anti-Markovnikov Additions to Terminal Alkynes and Alkene Metathesis.

код для вставкиСкачать
Reviews
C. Bruneau and P. H. Dixneuf
Organometallic Catalysis
DOI: 10.1002/anie.200501391
Metal Vinylidenes and Allenylidenes in Catalysis:
Applications in Anti-Markovnikov Additions to
Terminal Alkynes and Alkene Metathesis
Christian Bruneau* and Pierre H. Dixneuf*
Keywords:
alkene metathesis · allenylidenes · antiMarkovnikov addition · homogeneous catalysis · vinylidenes
Angewandte
Chemie
2176
www.angewandte.org
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
The involvement of a catalytic metal vinylidene species was
proposed for the first time in 1986 to explain the regioselective
formation of vinyl carbamates directly from terminal alkynes,
carbon dioxide, and amines. Since this initial report, various
metal vinylidenes and allenylidenes, which are key activation
intermediates, have proved extremely useful for many alkyne
transformations. They have contributed to the rational design of
new catalytic reactions. This 20th anniversary is a suitable
occasion to present the advancement of organometallic vinylidenes and allenylidenes in catalysis.
1. Introduction
2177
2. Catalytic Synthesis of Alkenyl
Carbamates and Ureas: The Early Days 2178
3. Anti-Markovnikov Additions to
Terminal Alkynes: Carbon–Heteroatom
Coupling
2179
4. Metal Vinylidenes in Catalytic CC
Bond Formation
2185
5. Metal Vinylidenes in Alkene and Enyne
Metathesis
2189
1. Introduction
The stabilization of vinylidenes or allenylidenes upon
coordination to a metal center is now a common feature
encountered with many transition metals. The synthesis and
stoichiometric reactivity of these unsaturated ligands have
been broadly developed but are still under active investigation, and several aspects have already led to reviews.[1–14] Since
the first mononuclear vinylidene complexes reported in
1972,[15] the most straightforward routes to vinylidene and
allenylidene complexes is the direct activation of terminal
alkynes and propargylic alcohols, respectively, thus allowing
the involvement of these species in catalytic reactions from
accessible acetylenic substrates.
The initial activation of alkynes into vinylidenes proceeds
by h2-coordination of the triple bond followed by 1,2-H
migration,[16–19] or oxidative addition of the alkyne C(sp)H
bond to give an alkynyl metal intermediate, which rearranges
through 1,3-H migration or by protonation.[2, 20–22] To rationalize the alternative pathways, several theoretical studies have
been carried out,[23–26] and recent experimental and theoretical studies have demonstrated that a bimolecular mode for
the h2-alkyne–h1-vinylidene isomerization process was also
possible.[27, 28] Vinylidenes can also be produced from ruthenium hydride complexes by insertion of the triple bond to
form a vinyl ruthenium species followed by a-H migration.[29, 30] Internal alkynes bearing a labile substituent are also
prone to form vinylidene derivatives. Trialkylsilyl,[31–37]
alkylthiol,[38] triphenylstannane,[39] and iodide[40, 41] are able
to migrate and generate functionalized vinylidene metal
complexes, and some of them have been involved in catalytic
reactions.
The activation of propargylic alcohols to give allenylidene
metal complexes M=C=C=CR2 involves dehydration. This
process mostly occurs via vinylidene intermediates, which
have been observed or isolated as electron-rich metal
complexes.
Vinylidenes and allenylidenes behave as electron-withdrawing ligands, thus both are subject to electrophilic
additions and can be stabilized by electron-rich metal fragments.[1, 8] To involve metal vinylidene and allenylidene
intermediates in catalytic processes, the metal moiety must
be chosen to allow a good compromise between ligand
electrophilicity and metal–ligand bond stability.
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
From the Contents
6. Metal Allenylidenes in Catalysis
2192
7. Ruthenium Allenylidenes as Catalyst
Precursors in Alkene Metathesis
2195
8. Conclusions and Outlook
2199
The vinylidene ligand usually contains an electrophilic,
coordinated carbon atom in the M=C=CHR moiety, as in any
heteroallene, but also exhibits metal carbene M=C character.
Thus, the three most-favored chemical processes leading to
catalytic reactions are: 1) addition of nucleophiles at the
coordinated Ca, 2) alkyl, alkenyl, or alkynyl migration from
the metal center to Ca, 3) [2+2] cycloaddition of M=C with
C=C or CC bonds with formation of metallacyclobutane and
metallacyclobutene intermediates.
The coordinated allenylidenes are electrophilic and lead
to nucleophilic additions at Ca, when the metal moiety does
not sterically disfavor this addition, and at Cg, whereas
protonation and electrophilic additions preferentially take
place at Cb.[6–8, 32]
The importance of metal vinylidene intermediates in
catalysis has been pointed out in recent years,[7, 9, 42] and
especially the specific aspects of ruthenium vinylidenes.[43]
This Review presents the various aspects of metal vinylidene
and allenylidene species in catalysis, with a special focus on
the contribution of our own group. We wish to update our
previous review on this topic[44] by showing recent advances in
the field.
The formation of metal vinylidenes has been used to
rationalize the anti-Markovnikov additions to alkynes. How-
[*] Dr. C. Bruneau, Prof. P. H. Dixneuf
Institut de Chimie, UMR 6509, CNRS-Universit1 de Rennes 1
Organom1talliques et Catalyse:
Chimie et Electrochimie Mol1culaires
Campus de Beaulieu, 35042 Rennes Cedex (France)
Fax: (+ 33) 2-2323-6939
E-mail: christian.bruneau@univ-rennes1.fr
pierre.dixneuf@univ-rennes1.fr
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2177
Reviews
C. Bruneau and P. H. Dixneuf
ever, evidence for vinylidene intermediates has not always
been demonstrated; nevertheless, these anti-Markovnikov
additions to terminal alkynes, when they are selective, will be
presented as well.
Metal allenylidene intermediates in catalysis are part of
an emerging field. Their formation has led to the development
of direct propargylation reactions. They can also explain some
unexpected catalytic reactions, although they have not been
fully characterized. In other examples, metal allenylidenes
have definitely been proved to be the precursors of catalytic
species. The following aspects are discussed:
*
*
*
*
*
With these catalysts, the reaction was shown to be specific
to terminal alkynes, afforded only the anti-Markovnikov
product (by addition of the carbamate to the terminal carbon
atom of the alkyne), and was accompanied by the formation
of a small amount of the alkyne head-to-head dimerization
product. To explain all these observations, the formation of a
metal vinylidene intermediate in catalysis was suggested for
the first time,[46] and the following cycle was proposed
(Scheme 2). Only the direct protonation of the ruthenium
atom is still in question now, as the ruthenium–carbon bond
can be directly protonated.
Metal vinylidenes in catalysis
Formation of carbon–heteroatom bonds and anti-Markovnikov addition to alkynes;
Carbon–carbon bond-forming reactions;
Alkene metathesis.
Metal allenylidenes in catalysis
Application as propargylation intermediates;
Application as precursors of alkene metathesis catalysts.
2. Catalytic Synthesis of Alkenyl Carbamates and
Ureas: The Early Days
The first catalytic synthesis of alkenyl carbamates by the
combination of three substrates (alkyne, carbon dioxide,
secondary amine) involved [Ru3(CO)12] as catalyst precursor
(1986).[45] It was the first anti-Markovnikov catalytic addition
to alkynes with CO bond formation. It was soon found that
this reaction was better promoted by well-defined mononuclear
ruthenium
catalysts
such
as
[RuCl2(pyridine)2(norbornadiene)] and [RuCl2(PMe3)(arene)] in
acetonitrile under CO2 (50 atm) (Scheme 1).[46]
Scheme 1. Ruthenium-catalyzed synthesis of vinylic carbamates.
Scheme 2. Proposed catalytic cycle for the catalytic synthesis of vinylic
carbamates.[46]
A tungsten vinylidene [(CO)4W=C=CHR] intermediate
had been previously proposed as an initiator, thus not a
catalytic species, in the photochemically assisted polymerization of terminal alkynes by [W(CO)6].[47]
It was already known that metal vinylidenes readily form
upon the interaction of terminal alkynes with 16-electron
metal intermediates through the now well-known h2-alkyne!
h1-vinylidene rearrangement and that the vinylidene carbon
atom linked to the metal center was an electrophilic site on
the basis of several stoichiometric nucleophile additions.[1]
The ruthenium vinylidene intermediate could not be
observed in the catalytic synthesis of vinyl carbamates in an
autoclave. Model studies on one of the best catalytic
precursors, [RuCl2(PMe3)(C6Me6)], showed that it smoothly
reacted with terminal alkynes to generate a ruthenium
vinylidene species, which readily added alcohol to form
stable alkoxycarbene ruthenium complexes and thus tending
Christian Bruneau graduated in chemistry
from the Institut National Suprieur de
Chimie Industrielle de Rouen (France, 1974)
and obtained his PhD at the University of
Rennes (1979). He obtained a CNRS position in 1980, and from 1986 worked in the
field of molecular catalysis with P. H. Dixneuf. He is now mainly involved in Rucatalyzed selective transformations (metathesis, cycloisomerization, asymmetric catalysis). Since 2000, he has headed the CNRS
Univ. of Rennes research group “Organometallics and Catalysis” (UMR 6509).
2178
www.angewandte.org
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Pierre H. Dixneuf studied in Rennes
(France) and obtained his PhD with R.
Dabard, followed by postdoctoral work on
heterocyclic carbene complexes with M. F.
Lappert in Brighton (UK, 1972). He was
appointed Professor in Rennes (1978). His
interests include the design of carbon-rich
organometallic reagents and molecular catalysts, especially Ru catalysts, the discovery
and characterization of new catalytic pathways, the activation of alkynes via vinylidene
and allenylidene intermediates or unusual
oxidative couplings, and the selective catalytic formation of CC and C=C bonds.
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
to add nucleophiles at Ca (Scheme 3).[48, 49] Notably, such
unstable ruthenium vinylidene were characterized only
recently with the bulky phosphine PR3=PCy3.[50]
The formation of vinyl or dienyl carbamates was not
possible from primary amines and CO2. Cyclohexylamine and
acetylene under CO2 (50 bar) in the presence of RuCl3·x H2O
and PBu3 in toluene provided dicyclohexylurea.[55, 56] The
reaction was improved by using propargyl alcohol instead of
Scheme 6. Formation of symmetrical ureas from primary amines.
Scheme 3. Stoichiometric formation of ruthenium alkoxycarbenes via
ruthenium vinylidenes.[49]
The catalytic addition of carbamates was then applied to
specific alkynes and shown to be general.[51] The simple vinyl
carbamates were obtained by the reaction of acetylene with
an excess of secondary amine in the presence of either
RuCl3·x H2O[52] or [{RuCl2(norbornadiene)}n][53] as catalyst
precursors (Scheme 4). O-1-(1,3-Dienyl) carbamates, with the
acetylene, without additional solvent, and [RuCl2(PR3)(arene)] complexes as catalyst precursors (Scheme 6).[55]
This reaction likely resulted from addition of the primary
amine to a transient ruthenium vinylidene, followed by
nucleophilic addition of a second molecule of the amine at
the carbonyl carbon atom to generate the symmetrical urea.
Since this first catalytic application, many metal vinylidenes, especially ruthenium vinylidenes, were suggested or
proved to be key catalyst species in anti-Markovnikov
additions of heteroatom or carbon nucleophiles to terminal
alkynes. Some examples are presented in this Review.
3. Anti-Markovnikov Additions to Terminal Alkynes:
Carbon–Heteroatom Coupling
Scheme 4. Catalytic formation of vinyl carbamates from acetylene
(nbd = norbornadiene).
Z isomer as the major product, were more efficiently
obtained from 2-methyl-1-buten-3-yne, carbon dioxide, and
a secondary amine in the presence of [Ru(methallyl)2(diphenylphosphanylethane)] as catalyst precursor
(Scheme 5).[54] This carbamate synthesis avoids the use of
phosgene derivatives and thus presents advantages over the
classical route based on a carbamoyl chloride and an aldehyde
enolate.
Scheme 5. Preparation of dienyl carbamates from 1,3-enynes.
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
The formation of metal vinylidene intermediates creates
an electron deficiency at the coordinated carbon atom and
thus favors the anti-Markovnikov addition of nucleophiles to
terminal alkynes. Labeling experiments that indicate the 1,2migration of the terminal acetylenic proton also corroborate
this mechanism. Metal vinylidene intermediates have not
been observed in some anti-Markovnikov additions. Nevertheless, the usefulness of the transformations justifies a brief
discussion.
3.1. Catalytic Addition of Carboxylic Acids to Alkynes: A
Convenient Synthesis of 1-Alkenyl Esters
Carboxylic acids add to terminal alkynes in the presence
of a variety of ruthenium precursors that favor the Markovnikov addition to produce enol esters, which lead to geminal
esters.[57–60] The first generation of active catalysts included
[Ru3(CO)12],[61]
[Ru(cod)2]/PR3[62]
(cod = cycloocta-1,5dienyl), [RuCl2(PR3)(arene)],[63–65] and [{Ru(O2CH)(CO)2(PR3)}2],[66] which allowed the preparation of enol esters from
functionalized alkynes and acids. Carboxylic acids react with
propargylic alcohols in the presence of these catalytic systems,
but lead to b-ketoesters rather than to hydroxy enol
esters.[62, 67, 68] Recently, the catalytic addition of carboxylic
acids to alkynes was revisited with other ruthenium catalyst
systems, including [{RuCl2(p-cymene)}2]/P(furyl)3/base,[69]
[RuCl2(PCy3)2(=C=CHtBu)],
[RuCl2(PCy3)2(bis(mesityl)imidazolylidene)(=C=CHtBu)],
[RuCl(L)2(=C=
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2179
Reviews
C. Bruneau and P. H. Dixneuf
CHtBu)]BF4,[70] and salicylaldimine-containing ruthenium
complexes.[71–73]
Attempts were made to reverse the addition regioselectivity of carboxylic acids to alkynes in order to produce 1alkenyl esters, which are protected intermediates in the
selective transformation of alkynes into aldehydes. As vinylidenes are electron-withdrawing ligands, efforts were made to
introduce electron-rich ligands at the ruthenium center so as
to stabilize the vinylidene intermediates formed from the
alkyne. Ru(methallyl)2(diphenylphosphanylalkane) proved
to be successful and provided the first metal catalysts that
favored the anti-Markovnikov addition of carboxylic acids to
terminal alkynes to form Z and E enol esters with high
regioselectivity (Scheme 7).[74]
Table 1: Regioselective anti-Markovnikov addition of carboxylic acids to
alkynes.
Cat.[a] Acid[b]
I
PhCO2H
PhCO2H
CH3CO2H
CHCl2CO2H
CF3CO2H
Ph2CHCO2H
2,6-F2C6H3CO2H
l-Boc-PheOH
l-Boc-AlaOH
l-Cbz-AlaOH
CH2=CHCO2H
MeOCH2CO2H
2-HOC6H4CO2H
2-AcOC6H4CO2H
MeOCH2CO2H
n-C4H9CO2H
CH2=C(Me)CO2H
PhCO2H
p-ClC6H4CO2H
PhCO2H
n-C4H9CO2H
C4H9CCH
65 95
PhCCH
100 97
PhCCH
45 90
PhCCH
20 78
PhCCH
0 61
C4H9CCH
65 97
C4H9CCH
65 94
C4H9CCH
65 97
65 71
C4H9CCH
PhCCH
65 98
PhCCH
45 65
PhCCH
65 96
PhCCH
80 94
PhCCH
80 98
(Z)-MeOCH=CHCCH 65 69
(Z)-MeOCH=CHCCH 65 75
(Z)-MeOCH=CHCCH 65 60
(Z)-MeOCH=CHCCH 65 81
(Z)-MeOCH=CHCCH 65 68
65 92
CH2=C(Me)CCH
CH2=C(Me)CCH
45 77
98 [76]
96
99
100
100
100
96
100
94
100
99
97
100
100
99 [78]
98
97
98
99
99
100
II
PhCO2H
CH2=C(Me)CO2H
l-Boc-AlaOH
PhCO2H
PhCO2H
PhCO2H
PhCO2H
PhCO2H
PhCO2H
Me3SiCCH
Me3SiCCH
Me3SiCCH
MeOC(Me)2CCH
MeOC(Me)(Et)CCH
MeOC(nC5H11)HCCH
C3H5OC(nC5H11)HCCH
MeOC(Me)(iBu)CCH
MeOC(Me)(Ph)CCH
100 [76]
100
100
94 [79]
99
95
99
98
98
Scheme 7. Anti-Markovnikov addition of carboxylic acids to terminal
alkynes. dppe = Ph2PCH2CH2PPh2, dppb = Ph2P(CH2)4PPh2.
The best catalyst precursors were [Ru(methallyl)2(dppb)]
(I; dppb = diphenylphosphanylbutane) and [Ru(methallyl)2(dppe)] (II; dppe = diphenylphosphanylethane), which also
led to a remarkable stereoselectivity in favor of the Z isomer;
the overall reaction thus corresponds to a formal trans
addition of RC(O)O-H to the triple bond. The formation of
a vinylidene intermediate according to a mechanism proposed
by Wakatsuki by initial protonation of the ruthenium
center[75] cannot be excluded.
The choice of the appropriate catalyst precursor I or II
depends on the steric demand of both the alkyne and the
carboxylic acid. In the presence of catalytic amounts of I,
whose Ru(dppb) moiety is more sterically demanding than
the Ru(dppe) group of II, a variety of carboxylic acids add
with high regioselectivity to nonhindered substrates such as
phenylacetylene, 1-hexyne,[76] and diynes.[77] Aliphatic carboxylic acids, substituted aromatic acids, and N-protected
amino acids react under mild conditions and provide Z enol
esters with high regioselectivity and without racemization of
the stereogenic centers of optically pure amino acid derivatives. The reaction temperature, which allows complete
conversion with good regioselectivity, can be decreased
from 80 to 0 8C, when the acidity of the carboxylic acid
increases in the pKa range from 5 to 1.5. The milder conditions
lead to the highest regioselectivity (Z) of the addition
(Table 1).[76] Functionalized Z enol esters can be prepared in
nonpolar solvents such as toluene or pentane; conjugated
enynes selectively produce dienyl esters (Scheme 8,
Table 1).[78]
With more bulky alkynes such as trimethylsilylacetylene
or propargylic ethers, [Ru(methallyl)2(dppe)] (II), in which
the ruthenium site is less sterically hindered than that of I, is a
more suitable catalyst precursor. For instance, the addition of
benzoic acid to Me3SiCCH takes place at 60 8C in toluene in
2180
www.angewandte.org
T
Yield Z
Ref.
[8C] [%] sel.[c]
Alkyne
60
50
50
80
80
80
80
80
80
88
76
75
86
73
98
96
74
95
[a] I: [Ru(methallyl)2(dppb)]; II: [Ru(methallyl)2(dppe)]. [b] Boc = tertbutoxycarbonyl, Cbz = benzyloxycarbonyl. [c] Z selectivity: 100 Z/Z + E.
Scheme 8. Ruthenium-catalyzed synthesis of dienyl esters.
the presence of 1 mol % of both catalysts I and II; however, II
gives the (Z)-2-trimethylsilylethenyl benzoate in 88 % yield
after 3 h, whereas I leads to only 34 % yield after 24 h.
Similarly, the transformation of bulky propargylic ethers is
faster with II than with I. In both cases, very good
regioselectivity is obtained.[79]
Notably, the stereoselective formal trans addition of the
RCO2 and H fragments to the triple bond has never been
explained.
From catalyst I, we have shown that the first step of the
catalytic reaction is the formation of [Ru(O2CR)2(dppb)]
complexes with elimination of the allylic ligands upon
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
protonation by RCO2H. We have shown that these complexes
are also efficient catalysts for the anti-Markovnikov addition
and that the reaction does not proceed through insertion of
the triple bond into a Ru–carboxylate bond. As the O2CR
ligand binds reversibly in the h2 and h1 modes, a vacant site is
temporarily liberated at the metal center. The involvement of
a vinylidene intermediate resulting from coordination of the
alkyne was suggested.[76] Some ruthenium complexes containing the tris(pyrazolyl)borate (Tp) ligand, such as
[RuCl(Tp)(pyridine)2], [RuCl(Tp)(cod)], and [RuCl(Tp)(tmeda)] (tmeda = N,N,N’,N’-tetramethylenediamine), have
been applied in the addition of benzoic acid to phenylacetylene to produce selectively Z and E enol benzoates.[80]
The enynyl ruthenium complex [Ru(Tp)(PhC=C(Ph)C
CPh)(PMeiPr2)] is remarkably active in the production of
unsaturated lactones by endocyclization of a,w-alkynoic acids
(Scheme 9).[81] In this reaction the presence of the basic
phosphine favors the alkyne to vinylidene tautomerism and
allows the formation of macrocyclic enol lactones.
Scheme 9. Ruthenium-catalyzed formation of lactones through regioselective intramolecular addition.
More recently, new (arene)ruthenium catalysts that
promote anti-Markovnikov addition of carboxylic acids to
terminal alkynes have been developed, for example, [RuCln(p-cymene)(triazol-5-ylidene)] (n = 1, 2). The reaction produces Z and E enol esters, depending on both the catalyst and
the substrate.[82] The association of [{RuCl2(p-cymene)}2] with
P(p-ClC6H4)3 and dimethylaminopyridine at 60 8C in toluene
also affords the Z vinyl esters with very high regio- and
stereoselectivity.[69]
The anti-Markovnikov addition of benzoic acid to propargylic alcohols in the presence of the catalyst II at 50 8C in
toluene affords bifunctionalized 3-hydroxy-1-propen-1-yl
benzoates with a stereoselectivity in favor of the Z isomer,
depending
on
the
starting
propargylic
alcohol
(Scheme 10).[83, 84] These compounds, which are, in fact,
protected aldehydes, can be transformed upon thermal or
acidic treatment into conjugated enals, resulting from the
formal isomerization of propargylic alcohol.[83, 84]
3.2. Intermolecular Addition of Alcohols
The intermolecular addition of alcohols to alkynes is a
difficult reaction. To date, only allylic alcohols have undergone addition to phenylacetylene in the presence of
[RuCl(Tp)(pyridine)2] catalyst. The reaction produces allyl
b-styryl ether and 2-phenylpent-4-enal through a Claisen
rearrangement of the ether. This is a rare example of the
direct formation of a CO ether bond.[80]
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Scheme 10. Regioselective formation of functionalized hydroxylated 1alkenyl esters. PTSA = para-toluenesulfonic acid.
Whereas [RuCl(Cp*)(cod)] (Cp* = C5Me5) promotes the
oxidative coupling of allyl alcohol with alkynes and alkynols
to form g,d-unsaturated aldehydes[85, 86] and 5-methylenetetrahydropyrans,[87, 88] respectively, the reaction catalyzed by
[RuCl(Cp)(PPh3)2]/NH4PF6 promotes the formation of ruthenium vinylidene species and follows a completely different
pathway. The expected addition of the hydroxy group to the
vinylidene ligand takes place but is followed by a skeleton
rearrangement leading to unsaturated ketones.[89–91] The
mechanism of this reconstitutive condensation involves the
formation of an allyl acyl metal intermediate, which releases
the unsaturated ketone by CC bond formation
(Scheme 11).[92]
Scheme 11. Catalytic cycle for the [RuCl(Cp)(PPh3)2]/NH4PF6-catalyzed
addition of allylic alcohols to alkynes.
3.3. Intramolecular Addition of O-Nucleophiles: Cyclization of
w-Acetylene Alcohols, Epoxides, and Ketones
The stoichiometric metal-assisted cycloisomerization of
alkynols to oxacycloalkylidene complexes via hydroxylated
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2181
Reviews
C. Bruneau and P. H. Dixneuf
vinylidene metal intermediates is well documented for
Group 6–10 transition metals.[93] The catalytic version, illustrated by the endo cyclization of 3- and 4-alkyn-1-ols to give
cyclic five- and six-membered enol ethers has been extensively studied, especially with molybdenum[94] and tungsten[95, 96] carbonyl promoters (Scheme 12).[97, 98] [Mo(CO)6],
[W(CO)6], [W(CO)5(thf)], and [W(CO)5(Et3N)] are the most
commonly used catalyst precursors, and photochemical
activation is often used to generate the active promoters.
These catalytic systems usually do not exhibit high turnover
numbers, but are compatible with a variety of functional
groups such as ethers, esters, amides, and carbamates, and
thus have been used in sugar, aminosugar, and polyol
chemistry.[99–103] [Mo(CO)5(Et3N)] (10 mol %) also allowed
the azacyclization of 2-ethynylaniline into indole in 79 %
yield.[104]
ing and nucleophilic addition of the oxygen atom at the
vinylidene Ca position to provide furan derivatives according
to the general catalytic cycle described in Scheme 13.
[Mo(CO)5(Et3N)][108] (at room temperature) and [RuCl(Tp)(PPh3)(CH3CN)][109] are efficient catalysts for the preparation
of these substituted furans from ethynyloxiranes, as they
tolerate a variety of functional groups such as alcohols, ethers,
esters, nitriles, and tosylamides.
Scheme 13. Catalytic formation of furans from ethynyloxiranes via
metal vinylidene intermediates.
Scheme 12. Cyclization of acetylenic alcohols via metal vinylidene
intermediates.
Similar cycloisomerizations of homo- and bis-homopropargylic alcohols into five- and six-membered oxygen-containing heterocycles have been performed with RhI catalyst
precursors such as [{Rh(cod)Cl}2], in the presence of an
excess of an electron-poor phosphine such as a tris(monofluoro- or difluorophenyl)phosphine, or [RhCl(PAr3)3] without any further additive.[105] The electron-poor tris(p-fluorophenyl)phosphine
(in
the
complex
[RuCl(Cp){(pFC6H4)3P)}2]) in the presence of Bu4NPF6 and N-hydroxysuccinimide sodium salt selectively provided dihydropyrans
from pent-4-yn-1-ols.[106] Transient metal oxacarbenes can be
converted into cyclic esters by selective oxidation by adding
N-hydroxysuccinimide as a mild oxidant to a catalytic system
based on [RuCl(Cp)(cod)], trisfurylphosphine in the presence
of Bu4NBr, or Bu4NPF6 in a DMF/water mixture. The
preparation of a variety of g-butyrolactones from functionalized homopropargylic alcohols was thus possible.[107] dLactones were selectively obtained in satisfactory yields
from pent-4-yn-1-ols in the presence of [RuCl(Cp){(pMeOC6H4)3P}2] associated to excess electron-rich phosphine
(p-MeOC6H4)3P, Bu4NPF6, and NaHCO3.[106]
Ethynyloxiranes are also prone to generate metal vinylidene complexes, which can rearrange through oxirane open-
2182
www.angewandte.org
When the starting oxirane is an (o-ethynyl)phenyl epoxide, the reaction catalyzed by [Ru(Tp)(PPh3)(MeCN)2]PF6,
proceeds through oxygen transfer from the epoxide to the
terminal alkyne carbon atom and generates a reactive ketene,
leading to naphthol, alkylideneindanone, or ester derivatives,
depending on the nature of the substrate and the solvent
(Scheme 14).[110] In the presence of the same catalyst, 1-iodo2-naphthol and 2-iodobenzo[d]oxepin can be selectively
obtained from iodoalkynes in DMF and benzene, respectively.[111]
Tungsten– and chromium–carbonyl complexes activate
the terminal triple bond of 1-acyl-2-ethynylcyclopropanes to
generate metal vinylidene species, which undergo cyclopropane ring opening and cyclization into a seven-membered
oxacycloheptadienylidene by attack of the oxygen atom at the
electrophilic vinylidene carbon center. The formation of the
aromatic phenol is then favored (Scheme 15).[112, 113]
3.4. Addition of Water to Terminal Alkynes: Transformation of
Alkynes into Aldehydes
The hydration of terminal alkynes to form aldehydes
through anti-Markovnikov addition of water to a triple bond
was performed for the first time in the presence of arene
ruthenium catalysts such as [RuCl2(C6H6)(PPh2C6F5)]
(10 mol %) in the presence of PPh2(C6F5) (30 mol %) or
[{RuCl2(C6H6)}2] associated to an excess of the water-soluble
ligand (3-NaO3SC6H4)3P in alcohol (Scheme 16).[114] These
catalytic systems involved large amounts of metal catalyst and
additive, and the selectivity remained unsatisfactory. Cyclopentadienyl–ruthenium complexes bearing appropriate
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
Scheme 16. Ruthenium-catalyzed hydration of terminal alkynes.
Scheme 14. Ruthenium-catalyzed cyclization of (o-ethynyl)phenyl
epoxides.
Scheme 15. Tungsten- and chromium-catalyzed formation of phenols
from 1-acyl-2-ethynylcyclopropanes.
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
bidentate or monodentate phosphine ligands led to a
dramatic improvement of both the activity and regioselectivity of the reaction. For instance, [RuCl(Cp)(dppm)] is an
efficient catalyst and provides high selectivity and tolerates a
variety of functional groups at 100 8C.[115] The substitution of
classical phosphine or diphosphine by a phosphanylimidazole[116] or a phosphanylpyridine[117] ligand has led to new
catalyst precursors that are very active and regioselective in
water and allow the reaction to proceed at room temperature
(Scheme 16).
Remarkably, the indenyl complex [RuCl(indenyl)(PPh3)2]
is also efficient for the anti-Markovnikov hydration of
terminal alkynes in aqueous media and micellar solutions.[118]
This system can be applied to the hydration of propargylic
alcohols to produce b-hydroxyaldehydes selectively, in contrast to [RuCl(Cp)(PMe3)2] in 2-propanol, which leads to
enals through dehydration of the alcohol and hydration of the
triple bond.[119] On the basis of the isolation of intermediate
by-products, deuterium-labeling experiments, and DFT calculations, the mechanism is proposed to involve first protonation of a h2-alkyne–ruthenium(ii) species to give a ruthenium(iv) vinylidene intermediate via a RuIV vinyl species,
rather than the direct protonation of the vinylidene.[75]
Addition of water to the a-carbon atom of the ruthenium(iv)
vinylidene is then followed by reductive elimination and
releases the aldehyde (Scheme 17).
Scheme 17. Mechanism for ruthenium vinylidene formation and
catalytic hydration of terminal alkynes.
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2183
Reviews
C. Bruneau and P. H. Dixneuf
A new ruthenium-catalyzed tandem formation of CO
and CC bonds to produce cyclopentanones from terminal
1,5-enynes and water was recently reported.[120] It first
involves the addition of water to a ruthenium vinylidene
intermediate to form an acyl ruthenium moiety, and then the
formal insertion of an electron-deficient double bond into the
acyl–ruthenium bond. The most active precursor for this
transformation was found to be the trinuclear complex
[Ru3Cl5(dppm)3]PF6 (2 mol %, 120 8C, dioxane), and satisfactory yields (23–81 %) were obtained for this hydrative
cyclization.
3.5. Addition of Diphenylphosphine
The addition of secondary phosphines HPR2 to prop-2ynols in the presence of [RuCl(C5Me5)(cod)] or [RuCl(C5Me5)(PPh3)2] provides the first regio- and stereoselective
direct hydrophosphination of propargylic alcohols and leads
to bifunctionalized Z olefins (Scheme 18).[121] It was shown
Scheme 19. Mechanism for the addition of phosphines to propargylic
alcohols.
3.6. Catalytic Addition of N-Nucleophiles to Alkynes: Direct
Transformation of Alkynes into Nitriles and Enamide
Derivatives
A ruthenium vinylidene species is also proposed as the
key intermediate in the regioselective addition of 1,1dimethylhydrazine to terminal alkynes in the presence of
[RuCl(Tp)(PPh3)2] as catalyst precursor to give nitriles
(Scheme 20).[123] The addition of hydrazine to the vinylidene
ligand generates a hydrazino carbene, which loses dimethylamine and provides nitriles from aromatic and aliphatic
alkynes (Scheme 20).[123]
Scheme 18. Anti-Markovnikov addition of a secondary phosphine to
propargylic alcohols.
that [Ru(PR3)2C5Me5]X activate propargylic alcohols to give
the vinylidene complexes [Ru=C=CHCR2OH(PR3)2C5Me5]X
rather than the expected ruthenium allenylidenes [Ru=C=C=
CR2(PR3)2C5Me5]X.[122] Thus, this intermediate is subject to
nucleophilic addition at the coordinated carbon atom. Indeed,
the reaction of propargylic alcohols with diphenylphosphine
in the presence of [Ru(PPh3)2C5Me5]PF6 as catalyst affords
the anti-Markovnikov addition product (Scheme 18). However, the same transformation proceeds more readily in the
presence of [RuCl(C5Me5)(cod)], which in the presence of
PPh2H and NaPF6 (2 equiv) gives [Ru(C5Me5)(PPh2H)2]PF6.
Thus, the reaction of tertiary propargylic alcohols with
diphenylphosphine in the presence of Na2CO3 in refluxing
CHCl3 led to 3-diphenylphosphanylprop-2-enols in good
yields with high stereoselectivity in favor of the Z isomer
(75:25–95:5). The kinetic product is always the Z derivative,
but simple silica gel chromatography transforms it completely
into the E isomer.
As [Ru(C5Me5)(L)2]+ catalyzes the reaction, and as the 3hydroxy vinylidene intermediate [Ru=C=CHCH2OH(C5Me5)(PMe2Ph)2]PF6 was isolated upon reaction of [RuCl(C5Me5)(PMe2Ph)2], NaPF6, and HCCCH2OH,[122] the
mechanism shown in Scheme 19 is plausible.
2184
www.angewandte.org
Scheme 20. Ruthenium-catalyzed addition of dimethylhydrazine to
alkynes. THP = tetrahydropyranyl.
The direct addition of secondary amides to terminal
alkynes in the presence of [Ru3(CO)12] associated to PCy3 at
180 8C to form E and Z enamides was reported in 1995.[124]
Insertion of a triple bond into a RuH bond resulting from
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
NH activation was proposed as the preferred mechanism.
More recently, E enamides were formed regio- and stereoselectively in the presence of a catalytic system based on
[Ru(methallyl)2(cod)], tributylphosphine, and dimethylaminopyridine (DMAP) in toluene at 100 8C (Scheme 21).[125]
Scheme 22. Formation of ruthenium enynyl intermediates.
of a ruthenium vinylidene intermediate. Upon protonation of
this enynyl species by the acidic proton of the terminal alkyne,
enynes are selectively produced (Scheme 23).[126, 127] Depending on the ancillary ligands, the enynyl ruthenium can
rearrange into a cumulenyl ruthenium species, and protonolysis gives butatriene compounds (Scheme 23).[128–130] In
both cases, the products result from selective head-to-head
dimerization of the starting terminal alkyne.
Scheme 21. Ruthenium-catalyzed addition of secondary amido
derivatives to alkynes.
This catalytic system is closely related to our system, which
allows the addition of carboxylic acids to terminal alkynes
(see Section 3.1) and the addition of a variety of N-nucleophiles such as amides, lactams, anilides, ureas, and carbamates. Under similar conditions,[125] but in the presence of
Cy2PCH2PCy2 and water as additives, instead of PnBu3 and
DMAP, the catalytic anti-Markovnikov addition selectively
provides the Z isomers.
4. Metal Vinylidenes in Catalytic CC Bond
Formation
The formation of metal vinylidene intermediates has been
used to promote new carbon–carbon bond-forming reactions
by the addition of carbon centers to the electrophilic
vinylidene carbon atom. These reactions include dimerization
of terminal alkynes, cycloisomerization of conjugated dienynes and unconjugated enynes, and mixed coupling of
terminal alkynes and olefins through [2+2] cycloaddition.
4.1. Dimerization of Terminal Alkynes
The head-to-head dimerization of terminal alkynes into
enynes requires the coordination of two molecules of alkyne
at the metal center. The characterization of ruthenium enynyl
intermediates [Ru-C(=CHR)-CCR] (Scheme 22) during the
formation of enynes has revealed that the reaction does not
proceed through insertion of the triple bond into a metal–
alkynyl bond, as observed with palladium catalysts, but rather
involves the migration of an alkynyl ligand onto the Ca atom
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Scheme 23. Dimerization of terminal alkynes via ruthenium vinylidene
intermediates.
A variety of ruthenium complexes containing trispyrazolyl,[131–134] P(CH2CH2PR2)3,[126, 127] N(CH2CH2PR2)3,[135] pentamethylcyclopentadienyl,[136] indenyl,[137, 138] and maltolato
ligands,[139] the metathesis catalysts [RuCl2(PCy3)2(=CHPh)][140] and [RuCl2(PiPr3)2(=C=CHPh)],[141, 142] as well
as a dinuclear (C5H5)2Ru2 complex[143] promote the formation
of Z and E enynes. Polyaddition of 2,7-diethynyl-9,9-dioctylfluorene with [RuCl2(PiPr3)2(=C=CHPh)] in the presence of
N-methylpyrrolidine produces polymers containing the
enynyl fragment with high Z selectivity.[141]
On the other hand, the formation of butatrienes is favored
with bulky alkynes, for example, tert-butylacetylene or
benzylacetylene, in the presence of catalytic precursors such
as [RuH2(CO)(PPh3)2],[128] [Ru(cod)(cot)] (cot = cyclooctatriene),[128, 129] or [RuH3(C5H5)(PCy3)].[136, 144] The hydrative
dimerization of terminal alkynes catalyzed by [RhCl(PPh3)3]
in the presence of a stoichiometric amount of 2-amino-3picoline and benzoic acid (5 mol %) at 110 8C in toluene was
recently reported.[145] The proposed mechanism involves the
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2185
Reviews
C. Bruneau and P. H. Dixneuf
nucleophilic addition of the amino group of 2-amino-3picoline to a transient rhodium vinylidene species followed
by formation of an heterometallacycle, which upon reductive
elimination and hydrolysis provides conjugated enones
(Scheme 24).
4.2. Cycloisomerization of Conjugated Dienynes: Synthesis of
Polycyclic Compounds
We define conjugated dienynes as substrates that contain
a triple bond and two double bonds in conjugated positions,
one or two of them being part of an aromatic motif, even
though this type of carbon–carbon bond cannot be regarded
as an olefinic double bond. These structures allow the
elaboration of polycyclic systems via metal vinylidene intermediates. The addition of nucleophilic C=C bonds to electrophilic vinylidene carbon atoms has been attempted with a
variety of metal precursors.[147] The cycloisomerization of
conjugated 1,3-dien-5-ynes in the presence of a ruthenium
catalyst is expected to involve as key steps 1) the formation of
a ruthenium vinylidene intermediate, and 2) the electrocyclization of the dienyl vinylidene species with aromatization.
This reaction has been carried out with [RuCl2(p-cymene)(PPh3)] as catalyst precursor in the presence of NH4PF6 as
chloride abstractor, and polycyclic and heterocyclic aromatic
compounds have been obtained in good yields
(Scheme 26).[148] Labeling experiments have shown the 1,2migration of the terminal acetylenic hydrogen atom, which
strongly supports the formation of the ruthenium vinylidene
intermediate.[149]
Scheme 24. Rhodium-catalyzed hydrative dimerization of terminal
alkynes.
Aryl acetylenes dimerize to 1-aryl naphthalenes at 180 8C
in the presence of ruthenium and rhodium porphyrin
complexes. The formation of a porphyrin metal vinylidene,
which undergoes a Diels–Alder reaction with the triple bond
of the same terminal alkyne or another internal alkyne and
then H migration and aromatization, has been postulated to
explain this unprecedented type of cyclodimerization
(Scheme 25).[146]
Scheme 25. Ruthenium–porphyrin catalysts for unusual dimerization of
terminal alkynes into naphthalene derivatives.
2186
www.angewandte.org
Scheme 26. Ruthenium-catalyzed cycloisomerization of dienynes.
[RuTp(PPh3)(MeCN)2]PF6 also promotes these cycloaromatization reactions with substrates containing a more
substituted terminal double bond. When the external
double bond of the 1,3-dien-5-yne structure is substituted by
a halogen atom (mainly I), halogen migration takes place
during the cyclization.[150] When the same double bond is
substituted by a p-tolyl or a p-anisyl group, not only the
expected compounds are obtained but also those resulting
from a skeleton rearrangement arising from 5-endo-dig
cyclization and 1,2-aryl shift.[150] Finally, the presence of two
substituents at the terminal olefin leads to the formation of
the vinylidene ruthenium intermediate followed by 6-endodig cyclization and alkyl migration to form a naphthalene
derivative, and 5-endo-dig cyclization to produce an alkenyl
indene (Scheme 27).[151] All these possibilities are illustrated
in Scheme 28.[150, 151]
Trialkylsilyl alkynes can be activated by metal complexes
to generate metal vinylidene derivatives. As illustrated in
Scheme 29, rhodium complexes [{RhCl(CO)2}2][152] and
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
catalyzed radical cycloaromatizations were then described,
for example, that of acyclic enediyne at 50–80 8C with catalytic
[RhCl(iPr3P)2] (5 mol %) in the presence of Et3N.[154, 155]
Under milder conditions, the electrocyclization of aromatic enynes was successfully performed in the presence of
[W(CO)5(thf)] catalyst precursor (Scheme 30).[156] Substituted
Scheme 27. The 6-endo-dig and 5-endo-dig cyclization of dienynes.
Scheme 30. Tungsten-catalyzed aromatization of dienynes. TBS = tertbutyldimethylsilyl.
Scheme 28. Various possibilities for the cyclization/rearrangement of
dienynes via ruthenium vinylidene intermediates.
naphthalene derivatives were produced in excellent yields at
room temperature via neutral vinylidene tungsten(carbonyl)
species. Indirect evidence for tungsten vinylidene intermediates was given by the isolation of metal pyranylidene
complexes from b-ethynyl a,b-unsaturated esters.[157] Aromatic alkynyl imines react in a similar manner in refluxing
THF in the presence of [W(CO)5(thf)] (20 mol %) to give 2arylated quinolines (Scheme 31).[158]
Scheme 31. Tungsten-catalyzed cyclization of alkynyl imines.
Scheme 29. Rhodium-catalyzed cyclization of silylated dienynes.
[{RhCl(PiPr3)2}2][41] allow the aromatization of a dienyne
containing a trimethylsilyl-substituted triple bond. In this
process, the formation of the silylvinylidene rhodium species
results from 1,2-migration of the trimethylsilyl group.
Activation of a terminal aromatic 3-ene-1,5-diyne by
[RuCl(Cp)(PMe3)2] allowed the isolation of a ruthenium
vinylidene, which subsequently underwent stoichiometric
thermal cycloaromatization.[153] On the basis of the experiment, it was suggested the cycloaromatization was a radical
process involving a metal fragment. A series of rhodiumAngew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Carbocycles are also efficiently constructed from wacetylene silyl enol ethers at room temperature in the
presence of [W(CO)5(thf)] (10 mol %) as precatalyst
(Scheme 32).[159–161] The reaction involves the endo-dig cyclization of an intermediate ene-vinylidene tungsten moiety,
followed by formation of a ketone through elimination of
silanol, which is favored by the addition of 2 equivalents of
water in the reaction medium.
The possibility of generating iodovinylidene complexes
through activation of iodoalkyne by [W(CO)5(thf)] opens a
new route to produce iodo-substituted aromatic derivatives
through catalytic electrocyclization of 6-iodo-1,3-dien-5-ynes
(Scheme 33).[162] This reaction produces useful substrates for
further coupling reactions, but is restricted to iodo derivatives.
The cyclization of w-iodoacetylenic silyl enol ethers to
produce cyclic iodoalkenes also proceeds in the presence of
[W(CO)5(thf)], but requires a stoichiometric amount of
tungsten complex.[41, 162]
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2187
Reviews
C. Bruneau and P. H. Dixneuf
ligand to give a cyclobutylidene ring through [2+2] cycloaddition (Scheme 34).[166, 167]
Scheme 34. Stoichiometric [2+2] cycloaddition reactions involving the
vinylidene C=C and M=C double bonds.
Scheme 32. Cyclization of acetylene silyl enol ethers.
The first type of reaction has been extended to catalytic
reactions for the coupling of alkynes with olefins to produce
conjugated dienes, with favored head-to-head coupling, in the
presence of [RuClCp(PPh3)2]/NaPF6 as catalyst precursor
(Schemes 35 and 36).[168]
When the reaction is carried out with conjugated enynes
such as cycloalkenylacetylene or the corresponding trime-
Scheme 35. Ruthenium-catalyzed coupling of alkynes with olefins.
Scheme 33. Tungsten-catalyzed cycloisomerization of an iodoalkyne.
The preparation of 9-halophenanthrenes by cycloisomerization of 2-haloethynylbiphenyl substrates and 1,2-halide
migration in the presence of catalytic amounts of AuCl seems
to be the first example of gold vinylidene in catalysis.[163]
4.3. Coupling of Terminal Alkynes and Olefins
4.3.1. Intermolecular Coupling of Terminal Alkynes and Olefins
through [2+2] Cycloaddition
Several stoichiometric reactions have shown that an olefin
and a metal vinylidene moiety can undergo [2+2] cycloaddition. Thus, the vinylidene M=Ca bond reacts with a
bidentate olefinic ligand (cod or (buta-1,3-dienyl)diphenylphosphine) to generate h3-allyl ligands,[164, 165] whereas the
Ca=Cb double bond interacts with an allyldiphenylphosphine
2188
www.angewandte.org
Scheme 36. Postulated catalytic cycle for the ruthenium- and
palladium-catalyzed coupling of alkynes with olefins.
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
thylsilyl-protected alkyne, the ruthenium-catalyzed reaction
directly leads to bicyclic dienes through selective head-tohead coupling followed by thermal elecrocyclization.[169]
Notably, the same final products can be obtained from a
propargylic alcohol substrate such as 1-ethynylcyclohexanol,
which is known to generate a ruthenium vinylvinylidene
intermediate upon dehydration (Scheme 37).
Scheme 39. Formation of cyclopentadienes from Z enynes.
Scheme 37. Ruthenium-catalyzed coupling of propargylic alcohols or
conjugated enynes with styrene.
If the formation of an allylic intermediate is not favored
(Scheme 36), cyclopropane formation takes place. The formation of benzylidenecyclopropane is thus observed when
phenylacetylene is treated with strained cycloolefins in the
presence of a palladium precursor bearing phosphinous acid
ligands.[170] Vinylidenecyclopropanes are formed from propargylic acetates and result from the [2+2] cycloaddition of the
olefinic bond with a metal allenylidene intermediate.[170] To
our knowledge, these are the first examples of palladium
vinylidene and allenylidene intermediates in catalysis.
The alkenylation of pyridine derivatives with trimethylsilylacetylenes, which is performed at 150 8C with [RuCl(Cp)(PPh3)2]/NaPF6, is also assumed to involve a ruthenium
vinylidene intermediate and a [2+2] cycloaddition with the
coordinated pyridine group (Scheme 38).[171]
Scheme 38. Alkenylation of pyridine with alkynes.
4.3.2. Intramolecular CC Bond Formation from Enynes
The [RuTp(PPh3)(MeCN)2]PF6 precursor (10 mol %)
promotes the intramolecular formation of cyclopentadienes
from (Z)-3-en-1-ynes bearing a hydrogen atom at C5 in very
good yields (71–89 %) at 80 8C through a 1,5-sigmatropic
hydrogen shift within the ruthenium vinylidene intermediates
(Scheme 39).[172] The formation of cyclopentadiene (and
related isomers) derivatives is also possible from propargylic
alcohols able to release Z enynes upon dehydration catalyzed
by the same ruthenium precursor.
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
5. Metal Vinylidenes in Alkene and Enyne
Metathesis
5.1. Alkyne Polymerization and Ring-Opening Olefin Metathesis
with Metal Vinylidene Initiators
The first example of metal vinylidene as a polymerization
initiator was in the polymerization of phenylacetylene
through the generation of [(CO)4W=C=CHPh] in situ upon
photochemical activation of [W(CO)6].[47] This reaction was
further developed with other transition metals,[173, 174] and used
to produce block copolymers from norbornene and
alkynes.[175]
The discovery of well-defined ruthenium alkylidene
catalysts of the type [RuX2(=CHR)(PR3)2] for alkene metathesis[176–181] has motivated the preparation of homologous
vinylidene complexes such as [RuCl2(=C=CHR’)(PR3)2] and
their evaluation in ring-opening olefin-metathesis polymerization (ROMP).[182, 183] Their catalytic activity for ROMP was
first disclosed for [RuCl2(=C=CH2)(PCy3)2],[184] and then
extended to analogous precursors containing other phosphines (such as PPh3 and PiPr3) and a vinylidene ligand
generated from various alkynes (such as tert-butylacetylene,
phenylacetylene, ferrocenylacetylene, and p-methoxyphenylacetylene).[185, 186] The precatalysts [RuCl2(=C=CHR)(L)2]
have been used successfully for the ROMP of a variety of
functionalized norbornene derivatives including esters,
ethers,[187] and carboximides.[188] The molecular weight was
controlled by addition of vinyl ether and vinyl thioether as
chain-transfer reagents.[187, 189] ROMP of norbornene can be
initiated with the precursors [RuCl(C5Me5)(=C=CHPh)(PPh3)] and [RuCl(Tp)(=C=CHPh)(PPh3)], and their activity
is enhanced by addition of Lewis acids such as BF3·Et2O or
[PdCl2(MeCN)2].[190]
5.2. Alkene Metathesis with Vinylidenes Generated In Situ
Ruthenium vinylidene complexes that are active in
ROMP have also been shown to perform well in olefin-ringclosing and cross-metathesis reactions, which are now well
developed in fine chemistry for access to cyclic or macrocyclic
compounds and functionalized internal double bonds. As an
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2189
Reviews
2190
C. Bruneau and P. H. Dixneuf
example,
[RuCl2(=C=CHFc)(PCy3)2]
(Fc = ferrocenyl)
(2 mol %) catalyze the ring-closing metathesis of 1,6- and
1,7-dienes to produce five- and six-membered rings in more
than 90 % yield in CDCl3 at 60 8C, whereas enynes and
dienynes were also cyclized into alkenyl cycloalkenes according to a metathesis mechanism.[187]
Ruthenium carbene complexes bearing 1,3-imidazol-2ylidene or 1,3-imidazolin-2-ylidene instead of bulky basic
phosphine ligands[191] were shown to be more efficient
catalysts for both olefin and enyne metathesis.[191–201]
Attempts to produce more-active ruthenium vinylidene
catalysts by introduction of such heterocyclic diaminocarbene
ligands proved to be less successful, and the idea of catalytic
species generated in situ emerged. The first example of such a
catalytic system was based on [{RuCl2(p-cymene)}2], 1,3bis(mesityl)imidazolium chloride, sodium tert-butylate, and
tert-butylacetylene.[202] The system allowed the ring-closing
metathesis of a variety of dienyl malonates at 80 8C to afford
five-, six-, and seven-membered rings, the metathesis cyclization of enynes, the cross-metathesis of propenylbenzene, and
the ring-opening metathesis of cod. At the same time, we
reported that a catalytic system generated in situ from
[{RuCl2(p-cymene)}2], 1,3-bis(mesityl)imidazolium chloride,
and cesium carbonate (1:2:4) promoted the cyclization of
enynes to form the conjugated alkenyl cycloalkene compounds at 80 8C in toluene.[203] With a similar approach, but
using the saturated 1,3-bis(mesityl)imidazolinium chloride as
diaminocarbene precursor, attempts were made to generate
coordinatively unsaturated species III and then IV[204] in situ
(Scheme 40).
in situ expected to be of type III, cyclic siloxanes[204, 206] as well
as terpenoid derivatives[207, 208] presenting enyne structures
were selectively produced in good yields (Scheme 42).
Notably, the species III generated in situ is more active than
[RuCl2(NHC)(p-cymene)] (NHC = N-heterocyclic carbene)
precatalysts.[203]
Scheme 40. Generation of NHC ruthenium vinylidene species in situ.
Mes = mesityl.
Scheme 43. Ruthenium-catalyzed cycloisomerization of dienes.
Scheme 42. Rearrangement of enynes derived from terpenoids in the
presence of a three-component catalytic system.
However, the catalysts generated in situ did not promote
the ring-closing metathesis of 1,6-dienes expected in the
absence of an initiating carbene, but provided cycloisomerization compounds at 80 8C in very good yields
(Scheme 43).[209] As an attempt to produce a ruthenium
This approach was based on our previous observation that
the same precursor [{RuCl2(p-cymene)}2] and Cs2CO3 transform a benzimidazolium salt into a ruthenium carbene
complex and that the p-cymene ligand was labile
(Scheme 41).[205] Thus, with the catalytic species generated
vinylidene species of type IV, a catalyst was generated in situ
as previously, but in the presence of a terminal alkyne
(Scheme 40). This catalyst does, indeed, promote the RCM of
the same dienes. Especially in the presence of acetylene
(1 bar), an active alkene metathesis catalyst is at play
(Scheme 44).[209, 210] No cycloisomerization was observed
Scheme 41. Stoichiometric formation of a diaminocarbene–ruthenium
complex.
Scheme 44. Generation of an olefin-metathesis catalyst in the presence
of a terminal alkyne.
www.angewandte.org
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
under these conditions, although this reaction is faster than
RCM. Thus, in the presence of the ruthenium species III, the
alkyne (RCCH; R = Ph, nBu, H) rapidly generates another
catalytic species IV that inhibits the cycloisomerization
reaction in favor of the metathesis reaction. To rationalize
these reactivities, it was proposed that the first step is the
deprotonation of the imidazolinium salt to generate a NHC
carbene, which is trapped by the ruthenium center with
removal of the arene ligand and gives rise to a coordinatively
unsaturated ruthenium species III that catalyzes the metathesis or cycloisomerization of enynes and dienes. In the
presence of a terminal alkyne, a metal vinylidene intermediate IV is readily formed and provides an olefin-metathesis
catalyst (Scheme 45).[202, 209, 210]
Scheme 46. Transformation of enynes in the presence of
[RuCl(p-cymene)(PCy3)]OTf.
Scheme 47. Formation of ruthenium vinylidene complexes from Va.
dene complexes (R = Ph, CH2Ph) did not catalyze the RCM
of dienes, and previously generated allenylidene ruthenium
complexes[213–216] appeared to be less effective enyne-RCM
catalysts than those arising from Va and enynes. To elucidate
the nature of the catalytic species, the precursor V b, which
contains the stabilizing counteranion B(ArF)4 , was treated
with a stoichiometric amount of an enyne at 30 8C, and the
new alkenyl carbene complex VII was formed together with
acrolein. The formation of VII was explained as occurring via
the ruthenium vinylidene VI followed by a pericyclic retroene rearrangement (Scheme 48).[50] This hypothesis was
Scheme 45. Catalytic cycle for the four-component catalytic system
active in RCM.
5.3. Vinylidene Ruthenium Intermediates Generated In Situ as
Precursors of Alkenyl Carbene Metal Catalysts
Owing to the lack of initiating carbene, the 16-electron
complex [RuCl(PCy3)(p-cymene)]OTf does not transform
diallyl tosylamide into its ring-closing-metathesis product. In
contrast, it was surprising that the same precursor transformed mixed allyl propargyl ethers into their RCM products,[50] the alkenyl cycloalkenes usually resulting from the
action of an alkene-metathesis catalyst (Scheme 46).[178, 211, 212]
This catalytic reaction suggested that the complex [RuCl(p-cymene)(PCy3)]TfO (Va) activates the allyl propargyl
ether and generates a carbene-metathesis catalyst. First, it was
thought that a ruthenium vinylidene complex might be
formed from the ruthenium precursor and the terminal
alkynes as illustrated in Scheme 47. However, these vinyliAngew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Scheme 48. Formation of a ruthenium alkenylcarbene from a
propargylic enyne.
strengthened by the activation of propargyl propyl ether by
Va to give propanal and the corresponding alkenyl carbene
ruthenium complex VIII (Scheme 49).
Although the alkenyl carbene ruthenium complex VII,
which contains the B(ArF)4 anion, is not an efficient RCM
catalyst, complex VIII and the accompanying TfO anion
proved to be an efficient catalyst for the RCM of enynes with
activity analogous to that in the transformation of enynes in
the presence of Va. This confirms that intermediates VIII,
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2191
Reviews
C. Bruneau and P. H. Dixneuf
carbene species for olefin metathesis. The reverse process was
recently reported by Murakami et al., who proposed the
formation of a molybdenum vinylidene from a molybdenum
carbene, which appears to be a key catalytic intermediate for
the metathesis rearrangement of allenynes (Scheme 50).[221]
Scheme 49. Formation of a ruthenium alkenylcarbene through
activation of a propyl propargyl ether.
which arise from vinylidene intermediates of type VI, are
active species in this reaction. More importantly, the complex
VIII was revealed as an excellent catalyst for the RCM
reaction of a variety of dienes under mild conditions
(Table 2).
Table 2: Diene RCM reactions with complex VIII (2 mol %) at room
temperature.
TOF [h1]
t
Conv. [%]
1
1h
99
49
2
15 min
95
190
3
4h
99
12
4
2h
99
25
5
1h
99
49
Entry
Substrate
Product
This study shows several innovative aspects arising from
the vinylidene intermediate VI, the key activation species of
enynes with 16-electron complex V. It leads to a new method
to generate alkenyl carbene metal complexes from a propargyl ether and an allyl or an alkyl group. It is thus in contrast
to the previous methods to generate alkenyl carbene ruthenium by initial formation of allenylidene,[217] by activation of a
cyclopropene derivative[218] or propargyl chloride,[219] or by
stoichiometric metathesis of butadiene.[220] This reaction
readily generates new RCM catalysts for enynes and dienes.
It also offers a remarkable example of a molecule, the enyne,
that creates its own catalyst, the alkenyl carbene ruthenium,
to initiate its own catalytic transformation into an alkenyl
cycloalkene.
5.4. Molybdenum Vinylidene for Allenyne Metathesis
We have just shown that ruthenium vinylidenes either
isolated or generated in situ can generate active ruthenium
2192
www.angewandte.org
Scheme 50. Molybdenum-catalyzed allenyne metathesis.
The reaction takes place at room temperature and provides
conjugated vinyl allenes in good yields (71–84 %) which can
be used as 1,3-dienes for Diels–Alder reactions. The reaction
works well when Z = TsN, (MeO2C)C, BnN, but no reaction
occurs with terminal allenes, internal triple bonds, and ethers;
attempts to form six-membered rings were unsuccessful.
6. Metal Allenylidenes in Catalysis
The discovery by Selegue[222] that a 16-electron ruthenium
intermediate promotes the activation/dehydration of propargyl alcohols (which led to the generation of the first
ruthenium allenylidene complex) lay the path to a large
variety of metal allenylidene complexes from readily accessible propargyl alcohols. Several reviews summarize the
synthetic approaches and stoichiometric reactions.[5, 6, 8, 9, 223, 224]
These reactions revealed the electrophilic properties of the
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
Ca and Cg carbon atoms of the M=C=C=CR2 moiety in the
addition of alcohols and amines at Ca and that of phosphines
or hydride at Cg.[217, 225–227] In contrast, Cb is nucleophilic and is
readily protonated to give alkenyl carbyne metal complexes.[228, 229]
Only recently have metal allenylidene complexes or metal
allenylidene intermediates, generated in situ by activation of
propargyl alcohol derivatives, emerged as catalyst precursors
or catalyst intermediates.[43] Significant advances were
recently made in the direct propargylation of a variety of
substrates by propargyl alcohols[230–233] and in alkene metathesis promoted by ruthenium allenylidene complexes.[234]
Among the metal allenylidene species, mainly ruthenium
moieties were involved as catalytic intermediates and catalyst
precursors. The first example was reported in 1992 by Trost
and Flygare, who showed that [RuCl(Cp)(PPh3)2]/NH4PF6
was an efficient catalyst for coupling hydroxylated propargylic alcohols with allylic alcohol according to Scheme 51.[235]
(Scheme 53). This reaction corresponds to the formal substitution of the hydroxy group by an allyloxy group with
elimination of water and was thought to proceed through
nucleophilic addition of the alcohol to Cg of a ruthenium
allenylidene intermediate.[236]
Scheme 53. Ruthenium-catalyzed formation of allyl propargyl ethers.
The more-efficient cationic 16-electron complex
[Ru(methallyl)(CO)(dppf)]SbF6 (dppf = diphenylphosphanylferrocene), generated upon chloride abstraction from
[RuCl(methallyl)(CO)(dppf)] with AgSbF6, produced a variety of propargylic ethers from 1,1-diphenylprop-2-yn-1-ol and
aliphatic alcohols (Scheme 54).[231] In the absence of any other
Scheme 51. Ruthenium-catalyzed coupling of propargylic and allylic
alcohols via ruthenium allenylidene intermediates.
This reaction is initiated by the formation of a ruthenium
allenylidene moiety, which undergoes an intramolecular
reaction with the hydroxy group at Cg to generate a
ruthenium vinylidene intermediate (Scheme 52). Then, upon
Scheme 54. Formation of propargylic ethers with
[Ru(methallyl)(CO)(dppf)]SbF6 as catalyst precursor.
Scheme 52. Catalytic cycle for the ruthenium-catalyzed coupling of
propargylic and allylic alcohols via a ruthenium allenylidene
intermediate.
intermolecular addition of the allylic alcohol and skeleton
rearrangement, the tetrahydrofuran compound bearing an
unsaturated ketone branch is formed (see Section 2.2)
At about the same time, we found that [RuCl2(PPh3)(pcymene)] promotes the formation of allyl propargyl ether
from allyl alcohol and 2-phenylbut-3-yn-2-ol at 60 8C
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
alcohol, the starting propargylic alcohol isomerized quantitatively into 3,3-diphenylprop-2-enal. Both compounds probably arise from the alkynol-activation process, which leads
first to a 3-hydroxyalkenylidene and then to an allenylidene
ruthenium intermediate, which reacts either with the freed
water at Ca to give the enal or with the nucleophilic alcohol at
Cg to form propargylic ethers.
We also recently reported the first propargylation of
furans catalyzed by the mononuclear ruthenium complexes
[RuCl(PR3)(p-cymene)]OTf (R = Ph, Cy) (Scheme 55).[232] A
study of the catalytic precursor, but with the B(ArF)4 anion,
showed that the two primary products, the ruthenium
allenylidene complex and water, which arises from dehydration of the propargylic alcohol, react by addition at Ca to
form a stable vinylic hydroxycarbene ruthenium intermediate, which upon heating at above 50 8C evolves into the
carbonyl cationic species [RuCl(PCy3)(CO)(p-cymene)]+.[232]
This complex exhibits good catalytic activity for the prop-
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2193
Reviews
C. Bruneau and P. H. Dixneuf
Scheme 55. Ruthenium-catalyzed propargylation of furans.
argylation of furans and is likely a catalytic species
(Scheme 56). However, a propargylic alcohol such as
nBuCCCH(Ph)OH also reacted with 2-methylfuran to
2194
Scheme 56. Transformation of [RuCl(PCy3)(CO)(p-cymene)][B(ArF)4] in
the presence of propargyl alcohol and water.
Scheme 57. Examples of propargylation of various nucleophiles.
form the corresponding 5-methylfuran-2-yl propargylic compound. This indicates that the formation of a metal allenylidene intermediate is not an essential condition in this
catalytic
reaction.
Dicationic
[Ru(MeCN)(pcymene)(bisoxazoline)](BF4)2 complexes were also used for
the propargylation of furan and arene derivatives.[233]
The most general results in the direct propargylation with
propargylic alcohols were obtained in the presence of
thiolate-bridged binuclear ruthenium precatalysts in the
series [(Cp*)RuCl(m2-SR)2RuCl(Cp*)] by Nishibayashi
et al.[230] This ruthenium-catalyzed substitution of propargylic
alcohols proceeded successfully with a variety of oxygen,
nitrogen, phosphorus, sulfur, and carbon nucleophiles, including aliphatic alcohols,[230, 237, 238] phenols,[230, 239] aromatic
amines,[237, 238]
amides,[237, 238]
phosphine
oxides,[237]
[237, 240]
[238, 241–245]
thiols,
ketones,
aromatic heterocycles,[238, 246]
[247]
and olefins
(Scheme 57). This catalyst also effects the
dehydration of propargylic alcohols.[230]
It has been shown that in most cases, the first step is the
addition of a nucleophile at the Cg atom of the allenylidene
that results from activation of the propargylic alcohol. The
second step is the ligand exchange between the vinylidene
formed at one of the ruthenium sites and another propargylic
alcohol, a determining step that is assumed to be facilitated by
the presence of the other ruthenium center, which is not
directly involved in the allenylidene formation (Scheme 58).
Scheme 58. General scheme for the propargylation of nucleophiles
catalyzed by diruthenium complexes.
www.angewandte.org
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
Several examples involving nucleophilic addition at the
coordinated allenylidene carbon atom have also been
reported. Thus, the addition of water to propargylic alcohols
in 2-propanol/water at 100 8C in the presence of catalytic
amounts of [RuCl(Cp)(PMe3)2] leads to conjugated enals with
E stereoselectivity (see Section 2.4).[119]
The activation of propargylic alcohols in the presence of
[RuTp(PPh3)(MeCN)2]PF6 provides a terminal olefin with
cleavage of the triple bond and elimination of carbon
monoxide (Scheme 59).[248] The reaction proceeds via a
Scheme 59. Catalytic transformations of propargylic alcohols and
ethers in the presence of [RuTp(PPh3)(CH3CN)2]PF6.
ruthenium allenylidene intermediate, which traps the
formed water molecule at Ca to generate an acyl ligand
that decomposes through decarbonylation. The reaction
proceeds in toluene at 110 8C in the presence of LiOTf
(20 mol %) and produces a variety of 4-aryl prop-1-enes in
good yields from 5-aryl pent-1-yn-3-ols.
The same catalyst [RuTp(PPh3)(MeCN)2]PF6 promotes
the conversion of 3-benzyl but-1-ynyl ethers into 1,3-dienes
and benzaldehyde (Scheme 59).[249, 250] When applied to cyclic
propargyl ethers, this transformation allows the formation of
dienes with a tethered aldehyde functionality. Another
application of this catalyst precursor led to the formation of
aryl and alkynyl ketones from aryl and alkynyl propargyl
ethers, respectively, in the presence of water through cleavage
of the carbon–carbon triple bond (Scheme 59).[251] These
transformations are based on the formation of a ruthenium
allenylidene intermediate with cleavage of the ether bond
followed by nucleophilic attack of the freed alcohol at the
allenylidene Ca atom and hydrogen transfer. Some of these
reactions can also be explained as occurring through vinylidene formation and retro-ene reaction of the benzyl group.[50]
7. Ruthenium Allenylidenes as Catalyst Precursors
in Alkene Metathesis
Ruthenium allenylidene complexes have, to date, found
very few applications in catalysis. Besides the dimerization of
tin hydrides, in which the [RuCp(=C=C=CPhAr)(PPh3)2]PF6
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
complex is transformed into a ruthenium alkynyl species,[252]
and the transetherification of tethered vinyl ethers,[253] the
main application of metal allenylidenes is in alkene metathesis.
7.1. The First Reaction Steps
Well-defined ruthenium alkylidenes of the type [RuCl2(PCy3)2(=CHR)] (R = Ph, CH=CR2) were revealed as efficient alkene metathesis and as functional-group-tolerant
catalysts.[180, 218, 254] They have initiated efforts for the search
of new neutral 16-electron ruthenium catalysts that contain an
initiating (DCHR) carbene ligand. The first metal allenylidene
complexes as alkene-metathesis precursors [RuCl(=C=C=
CR2)(PR3)(p-cymene)]X were reported in 1998.[255] These
ionic, 18-electron, well-defined precursors contain the DC=C=
CR2 moiety as an “initiator” and introduced a new orientation
in the search for catalysts. They raised questions about their
behavior in alkene metathesis. Applications of ruthenium
allenylidenes in various aspects of alkene metathesis of dienes
and enynes were first developed before the mechanism of the
reaction was solved.
The arene ruthenium allenylidene metathesis-catalyst
precursors were simply made from [RuCl2(PR3)(arene)]
complexes containing a bulky electron-releasing phosphine
after displacement of a chloride (Scheme 60). Their large-
Scheme 60. Straightforward preparation of the ruthenium allenylidene
catalyst precursor IX a.
scale preparation from commercially available [{RuCl2(pcymene)}2] can be carried out in one pot. The activity of the
catalysts, which is evaluated from the product yields and
reaction times (turnover frequency (TOF)) of the RCM
reaction of the diene to form the cyclic alkene (Scheme 61),
increases with the electron richness of phosphine ligand in the
order PPh3 ! PiPr3 < PCy3.[255] The counteranion of these
ionic precursors has a dramatic influence on the catalytic
activity, which increases with the sequence BF4 ! BPh4 PF6 ! TfO .[216, 256]
[RuCl(=C=C=CR2)(PCy3)(p-cymene)]PF6 IX b was evaluated for the ring-closing metathesis of dienes and the
formation of macrocycles and showed an activity and func-
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2195
Reviews
C. Bruneau and P. H. Dixneuf
Scheme 61. RCM reaction with ruthenium allenylidene catalyst
precursors IX.
tional-group tolerance similar to those of [RuCl2(PCy3)2(=CHPh)] (Scheme 62).[216] Complex IX a also promotes the
RCM reaction of a family of a-aminophosphonates
(Scheme 63).[257] It is now well accepted that the transforma-
Scheme 64. Enyne metathesis catalyzed by the ruthenium allenylidene
precursor IX b.
Scheme 65. Preparation of fluorinated cyclic amino acid derivatives
involving enyne metathesis.
7.2. Ruthenium Allenylidenes in the Polymerization of Cyclic
Olefins
Scheme 62. Macrocycle formation catalyzed by ruthenium allenylidene
catalyst IX b. Fmoc = 9-fluorenylmethoxycarbonyl.
Scheme 63. Synthesis of fluorine-containing cyclic aminophosphonates
through diene RCM.
ROMP of cyclic olefins provides macromolecules with
evenly distributed functional groups and C=C bonds that can
be hydrogenated[260] or functionalized.[261] The complex IX a
readily initiates the ROMP of norbornene at room temperature and that of cyclooctene at 80 8C (Table 3).[262]
Preactivation of the catalyst before addition of the cyclic
olefin, either thermally or photochemically in order to favor
arene displacement and/or allenylidene rearrangement (see
Section 7.1), allows the ROMP of cyclooctene at room
temperature with rather good polydispersity. As the loss of
the arene ligand was suggested as a first step of initiation,
arene-free neutral and ionic ruthenium allenylidene complexes containing the dimethyl sulfoxide (dmso) ligand were
prepared. Although they constitute a new family of ruthenium allenylidenes, they are not more efficient for ROMP
than arene complexes, likely as a result of the strong dmso–
ruthenium bond (Scheme 66).[263]
tion of enynes into alkenyl cycloalkenes is promoted by
alkene-metathesis catalysts.[178, 211]
This cycloisomerization reaction is
Table 3: ROMP of cycloalkenes with ruthenium allenylidene catalysts.
also promoted by ruthenium alleMonomer
Catalyst
Ratio[a] Conditions
Yield M0[b]
PDI[c] cis[d]
nylidene precursors, for example,
3
[%]
(H10
)
[%]
the skeleton rearrangement of
propargyl allyl ethers into alkenylnorbornene [RuCl(=C=C=CPh2)(PCy3)1000:1 5 min, 22 8C
90
198
1.8
25
(p-cymene)]OTf
cycloalkenes in the presence of
cyclooctene [RuCl(=C=C=CPh2)(PCy3)1000:1 5 min, 80 8C
90
267
1.4
22
IX b (Scheme 64). However, the
(p-cymene)]OTf
activity increase significantly upon
cyclooctene [RuCl(=C=C=CPh2)(PCy3)150:1 UV, 2 h, 22 8C 99
143
1.8
–
preliminary photochemical activa(p-cymene)]OTf
tion as an attempt to displace the
norbornene RuCl2(=C=C=CPh2)(PCy3)2300:1 4 h, 60 8C
56
16
4.1
–
arene from the metal.[258] Ruthe(dmso)
300:1 4 h, 60 8C
70
37
3.9
15
norbornene [RuCl(=C=C=CPh2)(PCy3)nium allenylidenes also give access
(dmso)2]OTf
to functionalized fluorinated bicyclic amino esters through an initial
[a] Monomer/catalyst molar ratio. [b] Mn : molecular weight (number average) [g mol1]. [c] Polydis[259]
enyne-RCM step (Scheme 65).
persity of the polymer. [d] Percentage of cis double bonds in the polymer.
2196
www.angewandte.org
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
Scheme 66. Preparation of ruthenium–dmso allenylidene precursors.
7.3. Allenylidene Metal Complexes in Alkene Metathesis
produce small rings and macrocycles.[264, 266, 268–277] Precursor
XIII presumably affords the same catalytic species as the
Grubbs catalyst after the first reaction step with an alkene.
In contrast, Werner and co-workers produced an 18electron allenylidene ruthenium complex XIV containing a
hemilabile phosphine; however, the ORu bond was probably too stable to be readily displaced by an alkene in olefin
metathesis[278] (Scheme 69). Moise and Le Gendre introduced
a titanium(iv)-containing phosphine and produced complex
XV, which is analogous to precursor IX b and exhibits similar
activity[279] (Scheme 69).
The discovery of the alkene-metathesis activity of ruthenium allenylidene complexes [RuCl(=C=C=CR2)(PCy3)(arene)]+X led several groups to design new allenylidene
metal complexes and evaluate them in this reaction. The first
targets were the neutral analogues of the Grubbs catalysts
[RuCl2(=C=C=CR2)(PCy3)(L)] (L = PCy3, NHC). Nolan and
co-workers prepared neutral ruthenium allenylidene complexes such as X,[264] but their catalytic activity remained
moderate (Scheme 67). The ionic complex XI (analogous to
IX b but containing an NHC ligand) was also prepared, but its
activity did not reach that of IX.[265]
Scheme 69. Examples of ruthenium allenylidenes, potential metathesis
catalysts.
Our group undertook the preparation of arene ruthenium
allenylidene complexes with a chelating arene NHC ligand
(Scheme 70).[205] The neutral precursors XVI lead to unstable
Scheme 67. Examples of ruthenium allenylidene complexes.
The attempts to produce neutral allenylidene complexes
containing the poorer-electron-releasing ligand PPh3 failed,
and the indenylidene complex XII was obtained instead
(Scheme 68)[264, 266] This reaction suggested that the ruthenium
allenylidene was first generated, followed by intramolecular
rearrangement by electrophilic substitution of the aryl group
as observed for higher cumulenylidene ruthenium complexes.[267] FMrstner and co-workers showed that the related
indenylidene ruthenium complexes containing PCy3 (XIII) or
NHC as ligands were actually very efficient catalysts for the
ring-closing metathesis of a variety of functionalized dienes to
Scheme 68. Formation of ruthenium indenylidene complexes.
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Scheme 70. Ruthenium allenylidene complexes with chelating NHC
ligands.
ruthenium allenylidenes XVII. However, the resulting catalysts transform dienes either through alkene metathesis or
cycloisomerization. The nature of the substrate and the
solvent influence both activity and selectivity, but the activity
is always lower than that with nonchelating arene complexes.
However, the allenylidene complexes generated in situ
from benzimidazole–ruthenium(ii) precursors and propargylic alcohol in the presence of AgOTf selectively lead to
cycloisomerization of 1,6-dienes (Scheme 71);[280] formation
of the a-methylene pyrrolidine or the pyrroline derivative is
very strongly dependent on the nature of the benzimidazole
ligand. Thus, complexes XVIII a, b selectively afford the
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2197
Reviews
C. Bruneau and P. H. Dixneuf
Scheme 71. Ruthenium benzimidazole precursors for diene
cycloisomerization.
Scheme 72. Formation of an indenylidene ruthenium complex from
ruthenium allenylidene.
classic isomerization product A, whereas XVIII d more
readily leads further to the tetrasubstituted cyclic olefin B
(Table 4). However, no proof can be given that the allenylidene or rearranged indenylidene product is the catalyst for
such a reaction.
Table 4: Cycloisomerization of diallyl tosylamide at 80 8C with ruthenium
precursors XVIII a–d.
Catalyst
Solvent
t [h]
Conversion [%]
A [%]
XVIII a
XVIII b
XVIII d
XVIII d
XVIII d
XVIII d
PhCl
PhCl
PhMe
PhMe
PhCl
PhCl
18
10
4
10
6
10
100
100
100
100
98
100
100
100
100
60
B [%]
100
38
100
electron releasing ligands (PPh3) or by protonation when an
electron-rich ligand such as PCy3 is present. The addition of
acid to generate a dicationic species actually favors electrophilic substitution. In thermally initiated catalytic reactions,
allenylidene complexes IX a, b are progressively transformed
into the indenylidene active species, whereas the addition of
acid quantitatively generates species XX.
This catalyst XX proved to be very active in alkene
metathesis when the reaction takes place at 0 8C or at room
temperature. Thus, the catalyst XX generated in situ catalyzes
the RCM of dienes at 0 8C in high yield and short reaction
time (Scheme 73).[228] Very high turnover numbers, up to
106 h1, have also been attained in the ROMP of cyclooctene
(Table 5).
7.4. Alkene-Metathesis Catalysts from Ruthenium Allenylidenes
Kinetic studies of the ring-closing metathesis of diallyl
tosylamide in the presence of IX a, b by NMR and UV/Vis
spectroscopy revealed that they actually generate a new
cationic species.[281] The nature of this catalytic species was
established in another observation. It was noticed that
protonation of IX a with HBF4 led to a significant increase
in the catalyst activity in the RCM of diallyl tosylamide.[216, 256]
The addition of trifluoromethanesulfonic acid (TfOH) to IX a
in the polymerization of cyclooctene was even more dramatic:
for a cyclooctene/IX a ratio of 1000:1, the TOF for ROMP at
room temperature was 63 h1 and when TfOH (5 equiv
relative to IX a) was added, the TOF reached 57 200 h1.
1
H, 13C NMR spectroscopy showed that the addition of
1.2 equivalents of TfOH (relative to IX a) at 40 8C first
transforms the allenylidene complex into an unstable dicationic alkenylcarbyne complex XIX. At 20 8C, this intermediate XIX quantitatively rearranges into the new indenylidene complex XX with release of TfOH (Scheme 72).[228]
This was the first directly observed rearrangement of an
allenylidene complex into an indenylidene complex. This
observation confirmed the very reasonable hypothesis that
indenylidene is formed from an allenylidene metal complex
(Scheme 68). Thus, this rearrangement is favored by weakly
2198
www.angewandte.org
Scheme 73. RCM of dienes promoted by catalyst XX.
Table 5: Cyclooctene polymerization with catalysts XX at room
temperature.[a]
Cyclooctene/Ru
TfOH[b]
t
Yield
TOF[c]
1000:1
1000:1
10 000:1
100 000:1
–
5
5
100
15 h
1 min
5 min
5 min
95
95
97
88
63
57 200
116 400
1 096 000
[a] Cyclooctene: 4.5 H 103 mol. [b] TfOH (equiv relative to Ru (IX a)).
[c] Turnover frequency [h1].
Cyclopentene is a cyclic olefin that is difficult to polymerize. Polymerization occurs under [W(=CHtBu)(OtBu)2(NAr)] catalysis at 40 8C (monomer/W = 200:1).[282, 283]
Cyclopentene was polymerized with XX (generated in situ
from IX a) and TfOH (5 equiv) at 40 8C to give the polymer
in
91 %
yield
(cyclooctene/Ru = 1000:1;
TOF =
44 000 h1).[228] The ADMET polymerization of decadiene
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
was also performed with IX a and TfOH (5 equiv) at 0 8C in
12 h to give the polymer in 94 % yield (Scheme 74).[228]
Scheme 76. Ring opening and cross-metathesis catalyzed by a watersoluble ruthenium allenylidene complex.
Scheme 74. ADMET polymerization of 1,9-decadiene in the presence of
IX a and TfOH (5 equiv).
For practical aspects, the active ionic (arene)ruthenium
indenylidene catalyst precursors are readily prepared from
[{RuCl2(p-cymene)}2]. The complex IX a is first obtained in a
three-step one-pot sequence; protonation affords XX quantitatively which can be isolated or used as is. It can be
expected that the arene interacts more strongly with the
indenylidene ligand in XX than with the allenylidene in IX a;
arene release is thus favored and the active species XXI is
generated faster (Scheme 75).
Akiyama and Kobayashi immobilized [RuCl2(PR3)] moieties by coordination to arene rings of polystyrene; the
coordination polymer obtained was further transformed into
polystyrene–[{RuCl(=C=C=CR2)(PR3)}x] complexes. Good
activity in alkene metathesis was still observed after the
third recycling step. However, the conditions for catalyst
regeneration are rather drastic (20 mol % catalyst, 12 h,
iPrOH/hexane, reflux) and the allenylidene or indenylidene
moieties are probably not retained.[286]
Ionic liquids constitute an elegant solution for the
recycling of catalysts as they are nonvolatile, reusable, and
insoluble in many organic solvents, thus offering biphasic
catalytic systems.[287–289] The ionic nature of the well-defined
allenylidene ruthenium complexes makes them very soluble
in imidazolium salts. They promote RCM of dienes in
imidazolium salts containing triflate TfO or PF6 anions at
80 8C.[290] However, the activity in this medium is lower than in
a homogeneous phase (toluene), but the catalyst can be
recycled twice owing to its moderate stability. A ROMP was
carried out in an ionic liquid for the first time with
allenylidene ruthenium complex IX a in C1-methylated
methylbutylimidazolium salts. The catalyst can be recycled
four times without loss of activity.[291]
8. Conclusions and Outlook
Scheme 75. Generation of active catalytic species XXI.
The generation of catalyst XX in the presence of acid
might explain the results obtained by Picquet et al. in the
alkene metathesis with IX a in a protonated ionic liquid
(imidazole). The ionic liquid protonated IX a and accelerated
the formation of the active species XX and XXI in situ.[284]
7.5. Recyclable Ruthenium Allenylidenes
The weakness of any type of ruthenium alkene-metathesis
catalyst is connected to its low stability, which requires high
activity or high loading for compensation. There have,
however, been attempts to recover catalysts generated from
ruthenium allenylidene complexes. Peruzzini et al. prepared a
water-soluble ionic allenylidene complex [{RuCl(m-Cl)(=C=
C=CPh2)(Ph2PC6H4SO3)2}2]Na4 that allows the ring opening/
cross-coupling of cyclopentene with methyl acrylate in water
(Scheme 76).[285] Despite the moderate yields, it was shown
that allenylidene ruthenium catalysts can tolerate water.
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
The formation of vinylidene and allenylidene metal
complexes through activation of terminal alkynes and propargylic alcohols, respectively, has led to a variety of novel
catalytic organic transformations. This type of addition is now
possible for the formation of a large variety of carbon–
heteroatom bonds. Carbon–carbon bond-forming reactions
have been made possible by nucleophilic addition but also
through the involvement of the carbene M=C bond and the
Cb=Cg double bond, which have led to cycloaromatization,
cycloisomerization, and unusual [2+2] addition reactions.
The facile formation of allenylidene metal intermediates
provides an efficient route for the direct propargylation of a
variety of O-, N-, P-, S-, and C-nucleophiles by substitution at
Cg of propargylic alcohols. Addition at Ca is mainly observed
in the case of small nucleophiles such as water.
Vinylidene and allenylidene ruthenium complexes as well
as intermediates generated in situ have revealed efficient
catalytic activities in alkene and enyne metathesis. Studies of
these catalytic reactions at the metal center revealed subtle
transformations of these catalyst precursors, which allowed
new catalytic species such as metal carbenes and alkenyl
carbenes.
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2199
Reviews
C. Bruneau and P. H. Dixneuf
Further developments in the field of metal vinylidenes
and allenylidenes in catalysis can be foreseen, such as cascade
sequences involving several types of the elementary reactions
described herein.
Received: April 22, 2005
Published online: March 7, 2006
[1] M. I. Bruce, A. G. Swincer, Adv. Organomet. Chem. 1983, 22,
59.
[2] A. B. Antonova, A. A. Ioganson, Russ. Chem. Rev. 1989, 58,
1197.
[3] M. I. Bruce, Chem. Rev. 1991, 91, 197.
[4] H. Werner, J. Organomet. Chem. 1994, 475, 45.
[5] H. Werner, Chem. Commun. 1997, 903.
[6] M. I. Bruce, Chem. Rev. 1998, 98, 2797.
[7] M. C. Puerta, P. Valerga, Coord. Chem. Rev. 1999, 193–195, 977.
[8] S. Rigaut, D. Touchard, P. H. Dixneuf, Coord. Chem. Rev. 2004,
248, 1585.
[9] V. Cadierno, M. P. Gamasa, J. Gimeno, Coord. Chem. Rev.
2004, 248, 1627.
[10] H. Werner, Coord. Chem. Rev. 2004, 248, 1693.
[11] D. A. Valyaev, O. V. Semeikin, N. A. Ustynyuk, Coord. Chem.
Rev. 2004, 248, 1679.
[12] J. P. Selegue, Coord. Chem. Rev. 2004, 248, 1543.
[13] M. I. Bruce, Coord. Chem. Rev. 2004, 248, 1603.
[14] J. W. Herndon, Coord. Chem. Rev. 2004, 248, 3.
[15] R. B. King, M. S. Saran, J. Chem. Soc. Chem. Commun. 1972,
1053.
[16] J. Silvestre, R. Hoffmann, Helv. Chim. Acta 1985, 68, 1461.
[17] Y. Wakatsuki, N. Koga, H. Yamazaki, K. Morokuma, J. Am.
Chem. Soc. 1994, 116, 8105.
[18] M. A. Jimenez Tenorio, M. Jimenez Tenorio, M. C. Puerta, P.
Valerga, Organometallics 1997, 16, 5528.
[19] D. Touchard, P. Haquette, N. Pirio, L. Toupet, P. H. Dixneuf,
Organometallics 1993, 12, 3132.
[20] I. de los Rios, M. Jimenez Tenorio, M. C. Puerta, P. Valerga, J.
Am. Chem. Soc. 1997, 119, 6529.
[21] Y. Wakatsuki, J. Organomet. Chem. 2004, 689, 4092.
[22] E. Bustelo, J. J. Carbo, A. Lledos, K. Mereiter, M. C. Puerta, P.
Valerga, J. Am. Chem. Soc. 2003, 125, 3311.
[23] J. Ipaktschi, J. Mohseni-Ala, S. Uhlig, Eur. J. Inorg. Chem. 2003,
4313.
[24] R. Stegmann, G. Frenking, Organometallics 1998, 17, 2089.
[25] A. Marrone, C. Coletti, N. Re, Organometallics 2004, 23, 4952.
[26] F. De Angelis, A. Sgamellotti, N. Re, Organometallics 2002, 21,
5944.
[27] E. Bustelo, M. Jimenez-Tenorio, M. C. Puerta, P. Valerga, Eur.
J. Inorg. Chem. 2001, 2391.
[28] M. Baya, P. Crochet, M. A. Esteruelas, A. M. Lopez, J.
Modrego, E. Onate, Organometallics 2001, 20, 4291.
[29] M. Olivan, O. Eisenstein, K. G. Caulton, Organometallics 1997,
16, 2227.
[30] M. Olivan, E. Clot, O. Eisenstein, K. G. Caulton, Organometallics 1998, 17, 3091.
[31] H. Sakurai, T. Fujii, K. Sakamoto, Chem. Lett. 1992, 339.
[32] N. G. Connelly, A. G. Orpen, A. L. Rieger, P. H. Rieger, J.
Chem. Soc. Chem. Commun. 1992, 1293.
[33] H. Werner, M. Baum, D. Schneider, B. WindmMller, Organometallics 1994, 13, 1089.
[34] D. Peron, A. Romero, P. H. Dixneuf, Gazz. Chim. Ital. 1994,
124, 497.
[35] D. Schneider, H. Werner, Angew. Chem. 1991, 103, 710; Angew.
Chem. Int. Ed. Engl. 1991, 30, 700.
2200
www.angewandte.org
[36] J. Foerstner, A. Kakoschke, R. Goddard, J. Rust, R. Wartchow,
H. ButenschQn, J. Organomet. Chem. 2001, 617–618, 412.
[37] H. Katayama, K. Onitsuka, F. Ozawa, Organometallics 1996,
15, 4642.
[38] D. C. Miller, R. J. Angelici, Organometallics 1991, 10, 79.
[39] M. Baum, N. Mahr, H. Werner, Chem. Ber. 1994, 127, 1877.
[40] C. LQwe, H.-U. Hund, H. Berke, J. Organomet. Chem. 1989,
371, 311.
[41] T. Miura, H. Murata, K. Kiyota, H. Kusama, N. Iwasawa, J. Mol.
Catal. A 2004, 213, 59.
[42] F. Alonso, I. P. Beletskaya, M. Yus, Chem. Rev. 2004, 104, 3079.
[43] C. Bruneau, Top. Organomet. Chem. 2004, 11, 125.
[44] C. Bruneau, P. H. Dixneuf, Acc. Chem. Res. 1999, 32, 311.
[45] Y. Sasaki, P. H. Dixneuf, J. Chem. Soc. Chem. Commun. 1986,
790.
[46] R. MahR, P. H. Dixneuf, S. LRcolier, Tetrahedron Lett. 1986, 27,
6333.
[47] S. J. Landon, P. M. Shulman, G. L. Geoffroy, J. Am. Chem. Soc.
1985, 107, 6739.
[48] K. Ouzzine, H. Le Bozec, P. H. Dixneuf, J. Organomet. Chem.
1986, 317, C25.
[49] H. Le Bozec, K. Ouzzine, P. H. Dixneuf, Organometallics 1991,
10, 2768.
[50] R. Castarlenas, M. Eckert, P. H. Dixneuf, Angew. Chem. 2005,
117, 2632; Angew. Chem. Int. Ed. 2005, 44, 2576.
[51] R. MahR, Y. Sasaki, C. Bruneau, P. H. Dixneuf, J. Org. Chem.
1989, 54, 1518.
[52] Y. Sasaki, P. H. Dixneuf, J. Org. Chem. 1987, 52, 314.
[53] C. Bruneau, P. H. Dixneuf, S. LRcolier, J. Mol. Catal. 1988, 44,
175.
[54] J. HQfer, H. Doucet, C. Bruneau, P. H. Dixneuf, Tetrahedron
Lett. 1991, 32, 7409.
[55] J. Fournier, C. Bruneau, P. H. Dixneuf, S. LRcolier, J. Org.
Chem. 1991, 56, 4456.
[56] C. Bruneau, P. H. Dixneuf, J. Mol. Catal. 1992, 74, 97.
[57] C. Fischmeister, C. Bruneau, P. H. Dixneuf, Ruthenium in
Organic Synthesis (Ed.: S.-I. Murahashi), Wiley-VCH, Weinheim, 2004, p. 189.
[58] C. Bruneau, M. Neveux, Z. Kabouche, C. Ruppin, P. H.
Dixneuf, Synlett 1991, 755.
[59] C. Bruneau, P. H. Dixneuf, Chem. Commun. 1997, 507.
[60] P. H. Dixneuf, C. Bruneau, Transition Metal Catalysed Reactions (Eds.: S.-I. Murahashi, S. G. Davis), Blackwell, Oxford,
1991, p. 391.
[61] M. Rotem, Y. Shvo, Organometallics 1983, 2, 1689.
[62] T. Mitsudo, Y. Hori, Y. Yamakawa, Y. Watanabe, J. Org. Chem.
1987, 52, 2230.
[63] C. Ruppin, P. H. Dixneuf, Tetrahedron Lett. 1986, 27, 6323.
[64] C. Ruppin, P. H. Dixneuf, S. LRcolier, Tetrahedron Lett. 1988,
29, 5365.
[65] K. Philippot, D. Devanne, P. H. Dixneuf, J. Chem. Soc. Chem.
Commun. 1990, 1199.
[66] M. Neveux, B. Seiller, F. Hagedorn, C. Bruneau, P. H. Dixneuf,
J. Organomet. Chem. 1993, 451, 133.
[67] D. Devanne, C. Ruppin, P. H. Dixneuf, J. Org. Chem. 1988, 53,
925.
[68] C. Bruneau, Z. Kabouche, M. Neveux, B. Seiller, P. H. Dixneuf,
Inorg. Chim. Acta 1994, 222, 154.
[69] L. J. Goossen, J. Paetzold, D. Koley, Chem. Commun. 2003, 706.
[70] T. Opstal, F. Verpoort, Tetrahedron Lett. 2002, 43, 9259.
[71] T. Opstal, F. Verpoort, Synlett 2002, 935.
[72] B. De Clercq, F. Verpoort, J. Organomet. Chem. 2003, 672, 11.
[73] K. Melis, D. De Vos, P. Jacobs, F. Verpoort, J. Organomet.
Chem. 2003, 671, 131.
[74] H. Doucet, J. HQfer, C. Bruneau, P. H. Dixneuf, J. Chem. Soc.
Chem. Commun. 1993, 850.
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
[75] M. Tokunaga, T. Suzuki, N. Koga, T. Fukushima, A. Horiuchi,
Y. Wakatsuki, J. Am. Chem. Soc. 2001, 123, 11 917.
[76] H. Doucet, B. Martin-Vaca, C. Bruneau, P. H. Dixneuf, J. Org.
Chem. 1995, 60, 7247.
[77] A. Kabouche, Z. Kabouche, C. Bruneau, P. H. Dixneuf, J.
Chem. Res. Miniprint 1999, 1247.
[78] H. Doucet, J. HQfer, N. Derrien, C. Bruneau, P. H. Dixneuf,
Bull. Soc. Chim. Fr. 1996, 133, 939.
[79] H. Doucet, N. Derrien, Z. Kabouche, C. Bruneau, P. H.
Dixneuf, J. Organomet. Chem. 1997, 551, 151.
[80] C. Gemel, G. Trimmel, C. Slugovc, S. Kremel, K. Mereiter, R.
Schmid, K. Kirchner, Organometallics 1996, 15, 3998.
[81] M. Jimenez Tenorio, M. C. Puerta, P. Valerga, F. J. MorenoDorado, F. M. Guerra, G. M. Massanet, Chem. Commun. 2001,
2324.
[82] K. Melis, P. Samulkiewiecz, J. Rynkowski, F. Verpoort,
Tetrahedron Lett. 2002, 43, 2713.
[83] M. Picquet, C. Bruneau, P. H. Dixneuf, Chem. Commun. 1997,
1201.
[84] M. Picquet, A. Fernandez, C. Bruneau, P. H. Dixneuf, Eur. J.
Org. Chem. 2000, 2361.
[85] S. DRrien, P. H. Dixneuf, J. Chem. Soc. Chem. Commun. 1994,
2551.
[86] S. DRrien, D. Jan, P. H. Dixneuf, Tetrahedron 1996, 52, 5511.
[87] S. DRrien, B. Gomez Vicente, P. H. Dixneuf, Chem. Commun.
1997, 1405.
[88] S. DRrien, P. H. Dixneuf, J. Organomet. Chem. 2004, 689, 1382.
[89] B. M. Trost, G. Dyker, R. J. Kulawiec, J. Am. Chem. Soc. 1990,
112, 7809.
[90] B. M. Trost, R. J. Kulawiec, A. Hammes, Tetrahedron Lett.
1993, 34, 587.
[91] B. M. Trost, J. A. Flygare, J. Org. Chem. 1994, 59, 1078.
[92] B. M. Trost, R. J. Kulawiec, J. Am. Chem. Soc. 1992, 114, 5579.
[93] B. Weyershausen, K. H. DQtz, Eur. J. Inorg. Chem. 1999, 1057.
[94] F. E. McDonald, C. B. Connolly, M. M. Gleason, T. B. Towne,
K. D. Treiber, J. Org. Chem. 1993, 58, 6952.
[95] F. E. McDonald, K. S. Reddy, Y. Diaz, J. Am. Chem. Soc. 2000,
122, 4304.
[96] Y. Sheng, D. Musaev, K. S. Reddy, F. E. McDonald, K.
Morokuma, J. Am. Chem. Soc. 2002, 124, 4149.
[97] F. E. McDonald, Chem. Eur. J. 1999, 5, 3103.
[98] T. Nowroozi-Isfahani, D. G. Musaev, F. E. McDonald, K.
Morokuma, Organometallics 2005, 24, 2921.
[99] F. E. McDonald, M. M. Gleason, Angew. Chem. 1995, 107, 356;
Angew. Chem. Int. Ed. Engl. 1995, 34, 350.
[100] F. E. McDonald, M. M. Gleason, J. Am. Chem. Soc. 1996, 118,
6648.
[101] P. Wipf, T. H. Graham, J. Org. Chem. 2003, 68, 8798.
[102] W. W. Cutchins, F. E. McDonald, Org. Lett. 2002, 4, 749.
[103] M. H. Davidson, F. E. McDonald, Org. Lett. 2004, 6, 1601.
[104] F. E. McDonald, A. K. Chatterjee, Tetrahedron Lett. 1997, 38,
7687.
[105] B. M. Trost, Y. H. Rhee, J. Am. Chem. Soc. 2003, 125, 7482.
[106] B. M. Trost, Y. H. Rhee, J. Am. Chem. Soc. 2002, 124, 2528.
[107] B. M. Trost, Y. H. Rhee, J. Am. Chem. Soc. 1999, 121, 11 680.
[108] F. E. McDonald, C. C. Schultz, J. Am. Chem. Soc. 1994, 116,
9363.
[109] C.-Y. Lo, H. Guo, J.-J. Lian, F.-M. Shen, R.-S. Liu, J. Org. Chem.
2002, 67, 3930.
[110] R. J. Madhushaw, M.-Y. Lin, S. M. Abu Sohel, R.-S. Liu, J. Am.
Chem. Soc. 2004, 126, 6895.
[111] M.-Y. Lin, S. J. Maddirala, R.-S. Liu, Org. Lett. 2005, 7, 1745.
[112] K. Ohe, T. Yokoi, F. Nishino, S. Uemura, J. Am. Chem. Soc.
2002, 124, 526.
[113] K. Miki, S. Uemura, K. Ohe, Chem. Lett. 2005, 34, 1068.
[114] M. Tokunaga, Y. Wakatsuki, Angew. Chem. 1998, 110, 3024;
Angew. Chem. Int. Ed. 1998, 37, 2867.
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
[115] T. Suzuki, M. Tokunaga, Y. Wakatsuki, Org. Lett. 2001, 3, 735.
[116] D. B. Grotjahn, C. D. Incarvito, A. L. Rheingold, Angew.
Chem. 2001, 113, 4002; Angew. Chem. Int. Ed. 2001, 40, 3884.
[117] D. B. Grotjahn, D. A. Lev, J. Am. Chem. Soc. 2004, 126, 12 232.
[118] P. Alvarez, M. Bassetti, J. Gimeno, G. Mancini, Tetrahedron
Lett. 2001, 42, 8467.
[119] T. Suzuki, M. Tokunaga, Y. Wakatsuki, Tetrahedron Lett. 2002,
43, 7531.
[120] Y. Chen, D. M. Ho, C. Lee, J. Am. Chem. Soc. 2005, 127, 12 184.
[121] F. JRrSme, F. Monnier, H. Lawicka, S. DRrien, P. H. Dixneuf,
Chem. Commun. 2003, 696.
[122] R. Le Lagadec, E. Roman, L. Toupet, U. MMller, P. H. Dixneuf,
Organometallics 1994, 13, 5030.
[123] Y. Fukumoto, T. Dohi, H. Masaoka, N. Chatani, S. Murai,
Organometallics 2002, 21, 3845.
[124] T. Kondo, A. Tanaka, S. Kotachi, Y. Watanabe, J. Chem. Soc.
Chem. Commun. 1995, 413.
[125] L. J. Goossen, J. E. Rauhaus, G. Deng, Angew. Chem. 2005, 117,
4110; Angew. Chem. Int. Ed. 2005, 44, 4042.
[126] C. Bianchini, M. Peruzzini, F. Zanobini, P. Frediani, A.
Albinati, J. Am. Chem. Soc. 1991, 113, 5453.
[127] C. Bianchini, P. Frediani, D. Masi, M. Peruzzini, F. Zanobini,
Organometallics 1994, 13, 4616.
[128] H. Yamazaki, J. Chem. Soc. Chem. Commun. 1976, 841.
[129] Y. Wakatsuki, H. Yamazaki, N. Kumegawa, T. Satoh, J. Y.
Satoh, J. Am. Chem. Soc. 1991, 113, 9604.
[130] Y. Wakatsuki, H. Yamazaki, J. Organomet. Chem. 1995, 500,
349.
[131] C. Slugovc, K. Mereiter, E. Zobetz, R. Schmid, K. Kirchner,
Organometallics 1996, 15, 5275.
[132] C. Slugovc, D. Doberer, C. Gemel, R. Schmid, K. Kirchner, B.
Winkler, F. Stelzer, Monatsh. Chem. 1998, 129, 221.
[133] S. Pavlik, C. Gemel, C. Slugovc, K. Mereiter, R. Schmid, K.
Kirchner, J. Organomet. Chem. 2001, 617–618, 301.
[134] M. A. Jimenez Tenorio, M. Jimenez Tenorio, M. C. Puerta, P.
Valerga, Organometallics 2000, 19, 1333.
[135] X. Chen, P. Xue, H. H. Y. Sung, I. D. Williams, M. Peruzzini, C.
Bianchini, G. Jia, Organometallics 2005, 24, 4330.
[136] C. S. Yi, N. Liu, Organometallics 1996, 15, 3968.
[137] M. Bassetti, S. Marini, F. Tortorella, V. Cadierno, J. Diez, M.
Pilar Gamasa, J. Gimeno, J. Organomet. Chem. 2000, 593–594,
292.
[138] M. Bassetti, S. Marini, J. Diaz, M. P. Gamasa, J. Gimeno, Y.
Rodriguez-Alvarez, S. Garcia-Grande, Organometallics 2002,
21, 4815.
[139] M. D. Fryzuk, M. J. Jonker, S. J. Rettig, Chem. Commun. 1997,
377.
[140] K. Melis, D. De Vos, P. Jacobs, F. Verpoort, J. Organomet.
Chem. 2002, 659, 159.
[141] H. Katayama, M. Nakayama, T. Nakano, C. Wada, K.
Akamatsu, F. Ozawa, Macromolecules 2004, 37, 13.
[142] H. Katayama, H. Yari, M. Tanaka, F. Ozawa, Chem. Commun.
2005, 4336.
[143] H. Matsuzaka, Y. Takagi, Y. Ishii, M. Nishio, M. Hidai,
Organometallics 1995, 14, 2153.
[144] C. S. Yi, N. Liu, Synlett 1999, 281.
[145] Y. J. Park, B.-I. Kwon, J.-A. Ahn, H. Lee, C.-H. Jun, J. Am.
Chem. Soc. 2004, 126, 13 892.
[146] E. Elakkari, B. Floris, P. Galloni, P. Tagliatesta, Eur. J. Org.
Chem. 2005, 889.
[147] C. Nevado, A. M. Echavarren, Synthesis 2005, 167.
[148] P. M. Donovan, L. T. Scott, J. Am. Chem. Soc. 2004, 126, 3108.
[149] C. A. Merlic, M. E. Pauly, J. Am. Chem. Soc. 1996, 118, 11 319.
[150] H.-C. Shen, S. Pal, J.-J. Lian, R.-S. Liu, J. Am. Chem. Soc. 2003,
125, 15 762.
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2201
Reviews
C. Bruneau and P. H. Dixneuf
[151] R. J. Madhushaw, C.-Y. Lo, C.-W. Hwang, M.-D. Su, H.-C.
Shen, S. Pal, I. R. Shaikh, R.-S. Liu, J. Am. Chem. Soc. 2004,
126, 15 560.
[152] J. W. Dankwardt, Tetrahedron Lett. 2001, 42, 5809.
[153] Y. Wang, M. G. Finn, J. Am. Chem. Soc. 1995, 117, 8045.
[154] K. Ohe, M. Kojima, K. Yonehara, S. Uemura, Angew. Chem.
1996, 108, 1823; Angew. Chem. Int. Ed. Engl. 1996, 35, 1823.
[155] T. Manabe, S. Yanagi, K. Ohe, S. Uemura, Organometallics
1998, 17, 2942.
[156] K. Maeyama, N. Iwasawa, J. Org. Chem. 1999, 64, 1344.
[157] K. Ohe, K. Miki, T. Yokoi, F. Nishino, S. Uemura, Organometallics 2000, 19, 5525.
[158] K. Sangu, K. Fuchibe, T. Akiyama, Org. Lett. 2004, 6, 353.
[159] K. Maeyama, N. Iwasawa, J. Am. Chem. Soc. 1998, 120, 1928.
[160] N. Iwasawa, T. Miura, K. Kiyota, H. Kusama, K. Lee, P. H. Lee,
Org. Lett. 2002, 4, 4463.
[161] H. Kusama, H. Yamabe, N. Iwasawa, Org. Lett. 2002, 4, 2569.
[162] T. Miura, N. Iwasawa, J. Am. Chem. Soc. 2002, 124, 518.
[163] V. Mamane, P. Hannen, A. FMrstner, Chem. Eur. J. 2004, 10,
4556.
[164] C. Slugovc, K. Mereiter, R. Schmid, K. Kirchner, J. Am. Chem.
Soc. 1998, 120, 6175.
[165] C. Slugovc, K. Mereiter, R. Schmid, K. Kirchner, Organometallics 1999, 18, 1011.
[166] P. Alvarez, E. Lastra, J. Gimeno, M. Bassetti, L. R. Falvello, J.
Am. Chem. Soc. 2003, 125, 2386.
[167] M. Bassetti, P. Alvarez, J. Gimeno, E. Lastra, Organometallics
2004, 23, 5127.
[168] M. Murakami, M. Ubukata, Y. Ito, Tetrahedron Lett. 1998, 39,
7361.
[169] M. Murakami, M. Ubukara, Y. Ito, Chem. Lett. 2002, 294.
[170] J. Bigeault, L. Giordano, G. Buono, Angew. Chem. 2005, 117,
4831; Angew. Chem. Int. Ed. 2005, 44, 4753.
[171] M. Murakami, S. Hori, J. Am. Chem. Soc. 2003, 125, 4720.
[172] S. Datta, A. Odedra, R.-S. Liu, J. Am. Chem. Soc. 2005, 127,
11 606.
[173] T. A. Vijayaraj, G. Sundararajan, J. Mol. Catal. A 1995, 99, 47.
[174] T. Szymanska-Buzar, J. Mol. Catal. 1994, 93, 137.
[175] B. Gita, G. Sundararajan, Tetrahedron Lett. 1993, 34, 6123.
[176] A. FMrstner, Top. Organomet. Chem. 1998, 1, 37.
[177] R. H. Grubbs, S. Chang, Tetrahedron 1998, 54, 4413.
[178] M. Mori, Top. Organomet. Chem. 1998, 1, 133.
[179] A. FMrstner, Angew. Chem. 2000, 112, 3140; Angew. Chem. Int.
Ed. 2000, 39, 3012.
[180] T. M. Trnka, R. H. Grubbs, Acc. Chem. Res. 2001, 34, 18.
[181] R. H. Grubbs, Handbook of metathesis, Wiley-VCH, Weinheim, 2003.
[182] H. Katayama, F. Ozawa, Coord. Chem. Rev. 2004, 248, 1703.
[183] V. Dragutan, I. Dragutan, Platinum Met. Rev. 2004, 48, 148.
[184] P. Schwab, R. H. Grubbs, J. W. Ziller, J. Am. Chem. Soc. 1996,
118, 100.
[185] H. Katayama, F. Ozawa, Chem. Lett. 1998, 67.
[186] H. Katayama, F. Ozawa, Organometallics 1998, 17, 5190.
[187] H. Katayama, H. Urushima, F. Ozawa, J. Organomet. Chem.
2000, 606, 16.
[188] A. Pineda Contreras, A. Masiel Cerda, M. A. Tlenkopatchev,
Macromol. Chem. Phys. 2002, 203, 1811.
[189] H. Katayama, F. Yonezawa, M. Nagao, F. Ozawa, Macromolecules 2002, 35, 1133.
[190] H. Katayama, T. Yoshida, F. Ozawa, J. Organomet. Chem. 1998,
562, 203.
[191] T. Weskamp, W. C. Schattenmann, M. Spiegler, W. A. Herrmann, Angew. Chem. 1998, 110, 2631; Angew. Chem. Int. Ed.
1998, 37, 2490.
[192] L. Ackermann, A. FMrstner, T. Weskamp, F. J. Kohl, W. A.
Herrmann, Tetrahedron Lett. 1999, 40, 4787.
[193] A. K. Chatterjee, R. H. Grubbs, Org. Lett. 1999, 1, 1751.
2202
www.angewandte.org
[194] L. Jafarpour, J. Huang, E. D. Stevens, S. P. Nolan, Organometallics 1999, 18, 3760.
[195] M. Scholl, S. Ding, C. W. Lee, R. H. Grubbs, Org. Lett. 1999, 1,
953.
[196] T. Weskamp, F. J. Kohl, W. Hieringer, D. Gleich, W. A.
Herrmann, Angew. Chem. 1999, 111, 2573; Angew. Chem. Int.
Ed. 1999, 38, 2416.
[197] A. K. Chatterjee, J. P. Morgan, M. Scholl, R. H. Grubbs, J. Am.
Chem. Soc. 2000, 122, 3783.
[198] C. W. Lee, R. H. Grubbs, Org. Lett. 2000, 2, 2145.
[199] J. P. Morgan, R. H. Grubbs, Org. Lett. 2000, 2, 3153.
[200] J. A. Smulik, S. T. Diver, Org. Lett. 2000, 2, 2271.
[201] D. L. Wright, J. P. Schulte II, M. A. Page, Org. Lett. 2000, 2,
1847.
[202] J. Louie, R. H. Grubbs, Angew. Chem. 2001, 113, 253; Angew.
Chem. Int. Ed. 2001, 40, 247.
[203] L. Ackermann, C. Bruneau, P. H. Dixneuf, Synlett 2001, 397.
[204] D. SRmeril, M. ClRran, C. Bruneau, P. H. Dixneuf, Adv. Synth.
Catal. 2001, 343, 184.
[205] B. Cetinkaya, S. Demir, I. Tzdemir, L. Toupet, D. SRmeril, C.
Bruneau, P. H. Dixneuf, Chem. Eur. J. 2003, 9, 2323.
[206] D. SRmeril, M. ClRran, A. Jimenez Perez, C. Bruneau, P. H.
Dixneuf, J. Mol. Catal. A 2002, 190, 9.
[207] J. Le NStre, C. Bruneau, P. H. Dixneuf, Eur. J. Org. Chem. 2002,
3816.
[208] J. Le NStre, A. Acosta Martinez, P. H. Dixneuf, C. Bruneau,
Tetrahedron 2003, 59, 9425.
[209] D. SRmeril, C. Bruneau, P. H. Dixneuf, Helv. Chim. Acta 2001,
84, 3335.
[210] D. SRmeril, C. Bruneau, P. H. Dixneuf, Adv. Synth. Catal. 2002,
344, 585.
[211] M. Mori, J. Mol. Catal. A 2004, 213, 73.
[212] S. T. Diver, A. J. Giessert, Chem. Rev. 2004, 104, 1317.
[213] A. FMrstner, M. Liebl, C. W. Lehmann, M. Picquet, R. Kunz, C.
Bruneau, D. Touchard, P. H. Dixneuf, Chem. Eur. J. 2000, 6,
1847.
[214] A. FMrstner, M. Picquet, C. Bruneau, P. H. Dixneuf, Chem.
Commun. 1998, 1315.
[215] M. Picquet, D. Touchard, C. Bruneau, P. H. Dixneuf, New J.
Chem. 1999, 23, 141.
[216] A. FMrstner, M. Liebl, C. W. Lehmann, M. Picquet, R. Kunz, C.
Bruneau, D. Touchard, P. H. Dixneuf, Chem. Eur. J. 2000, 6,
1847.
[217] D. Pilette, K. Ouzzine, H. Le Bozec, P. H. Dixneuf, C. E. F.
Rickard, W. R. Roper, Organometallics 1992, 11, 809.
[218] S. T. Nguyen, L. K. Johnson, R. H. Grubbs, J. W. Ziller, J. Am.
Chem. Soc. 1992, 114, 3974.
[219] T. E. Wilhelm, T. R. Belderrain, S. N. Brown, R. H. Grubbs,
Organometallics 1997, 16, 3867.
[220] P. Schwab, R. H. Grubbs, J. W. Ziller, J. Am. Chem. Soc. 1996,
118, 100.
[221] M. Murakami, S. Kadowaki, T. Matsuda, Org. Lett. 2005, 7,
3953.
[222] J. P. Selegue, Organometallics 1982, 1, 217.
[223] D. Touchard, P. H. Dixneuf, Coord. Chem. Rev. 1998, 178–180,
409.
[224] V. Cadierno, M. P. Gamasa, J. Gimeno, Eur. J. Inorg. Chem.
2001, 571.
[225] M. A. Esteruelas, A. V. Gomez, A. M. Lopez, J. Modrego, E.
Onate, Organometallics 1997, 16, 5826.
[226] S. Rigault, F. Monnier, F. Mousset, D. Touchard, P. H. Dixneuf,
Organometallics 2002, 21, 2654.
[227] V. Cadierno, S. Conejero, M. P. Gamasa, J. Gimeno, L. R.
Falvello, R. M. Llusar, Organometallics 2002, 21, 3716.
[228] R. Castarlenas, P. H. Dixneuf, Angew. Chem. 2003, 115, 4662;
Angew. Chem. Int. Ed. 2003, 42, 4524.
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
Angewandte
Chemie
Metal Vinylidenes and Allenylidenes
[229] S. Rigault, D. Touchard, P. H. Dixneuf, Organometallics 2003,
22, 3980.
[230] Y. Nishibayashi, M. D. Milton, Y. Inada, M. Yoshikawa, I.
Wakiji, M. Hidai, S. Uemura, Chem. Eur. J. 2005, 11, 1433.
[231] V. Cadierno, J. Diez, S. E. Garcia-Garrido, J. Gimeno, Chem.
Commun. 2004, 2716.
[232] E. Bustelo, P. H. Dixneuf, Adv. Synth. Catal. 2005, 347, 393.
[233] C. Fischmeister, L. Toupet, P. H. Dixneuf, New J. Chem. 2005,
29, 765.
[234] R. Castarlenas, C. Fischmeister, C. Bruneau, P. H. Dixneuf, J.
Mol. Catal. A 2004, 213, 31.
[235] B. M. Trost, J. A. Flygare, J. Am. Chem. Soc. 1992, 114, 5476.
[236] B. Seiller, DEA report, University of Rennes 1992.
[237] Y. Nishibayashi, I. Wakiji, M. Hidai, J. Am. Chem. Soc. 2000,
122, 11 019.
[238] Y. Nishibayashi, H. Imajima, G. Onodera, M. Hidai, S. Uemura,
Organometallics 2004, 23, 26.
[239] Y. Nishibayashi, Y. Inada, M. Hidai, S. Uemura, J. Am. Chem.
Soc. 2002, 124, 7900.
[240] Y. Inada, Y. Nishibayashi, M. Hidai, S. Uemura, J. Am. Chem.
Soc. 2002, 124, 15 172.
[241] Y. Nishibayashi, I. Wakiji, Y. Ishii, S. Uemura, M. Hidai, J. Am.
Chem. Soc. 2001, 123, 3393.
[242] Y. Nishibayashi, G. Onodera, Y. Inada, M. Hidai, S. Uemura,
Organometallics 2003, 22, 873.
[243] Y. Nishibayashi, M. Yoshikawa, Y. Inada, M. D. Milton, M.
Hidai, S. Uemura, Angew. Chem. 2003, 115, 2785; Angew.
Chem. Int. Ed. 2003, 42, 2681.
[244] Y. Nishibayashi, M. Yoshikawa, Y. Inada, M. Hidai, S. Uemura,
J. Org. Chem. 2004, 69, 3408.
[245] Y. Nishibayashi, H. Imajima, G. Onodera, Y. Inada, M. Hidai, S.
Uemura, Organometallics 2004, 23, 5100.
[246] Y. Nishibayashi, M. Yoshikawa, Y. Inada, M. Hidai, S. Uemura,
J. Am. Chem. Soc. 2002, 124, 11 846.
[247] Y. Nishibayashi, Y. Inada, M. Hidai, S. Uemura, J. Am. Chem.
Soc. 2003, 125, 6060.
[248] S. Datta, C.-L. Chang, K.-L. Yeh, R.-S. Liu, J. Am. Chem. Soc.
2003, 125, 9294.
[249] K.-L. Yeh, B. Liu, Y.-T. Lai, C.-W. Li, R.-S. Liu, J. Org. Chem.
2004, 69, 4692.
[250] K.-L. Yeh, B. Liu, C.-Y. Lo, H.-L. Huang, R.-S. Liu, J. Am.
Chem. Soc. 2002, 124, 6510.
[251] H.-C. Shen, H.-L. Su, Y.-C. Hsueh, R.-S. Liu, Organometallics
2004, 23, 4332.
[252] S. M. Maddock, M. G. Finn, Angew. Chem. 2001, 113, 2196;
Angew. Chem. Int. Ed. 2001, 40, 2138.
[253] M. Saoud, A. Romerosa, S. Manas Carpio, L. Gonsalvi, M.
Peruzzini, Eur. J. Inorg. Chem. 2003, 1614.
[254] S. T. Nguyen, R. H. Grubbs, J. Am. Chem. Soc. 1993, 115, 9858.
[255] A. FMrstner, M. Picquet, C. Bruneau, P. H. Dixneuf, Chem.
Commun. 1998, 1315.
[256] M. Picquet, D. Touchard, C. Bruneau, P. H. Dixneuf, New J.
Chem. 1999, 23, 141.
[257] S. N. Osipov, O. I. Artyushin, A. F. Kolomiets, C. Bruneau, M.
Picquet, P. H. Dixneuf, Eur. J. Org. Chem. 2001, 3891.
[258] M. Picquet, C. Bruneau, P. H. Dixneuf, Chem. Commun. 1998,
2249.
[259] D. SRmeril, J. Le NStre, C. Bruneau, P. H. Dixneuf, A. F.
Kolomiets, S. N. Osipov, New J. Chem. 2001, 25, 16.
Angew. Chem. Int. Ed. 2006, 45, 2176 – 2203
[260] S. D. Drouin, F. Zamanian, D. E. Fogg, Organometallics 2001,
20, 5495.
[261] C. W. Bielawski, J. Louie, R. H. Grubbs, J. Am. Chem. Soc.
2000, 122, 12 872.
[262] R. Castarlenas, D. SRmeril, A. F. Noels, A. Demonceau, P. H.
Dixneuf, J. Organomet. Chem. 2002, 663, 235.
[263] I. Alaoui Abdallaoui, D. SRmeril, P. H. Dixneuf, J. Mol. Catal. A
2002, 182–183, 577.
[264] H.-J. Schanz, L. Jafarpour, E. D. Stevens, S. P. Nolan, Organometallics 1999, 18, 5187.
[265] L. Jafarpour, J. Huang, E. D. Stevens, S. P. Nolan, Organometallics 1999, 18, 3760.
[266] A. FMrstner, O. Guth, A. Duffels, G. Seidel, M. Liebl, B. Gabor,
R. Mynott, Chem. Eur. J. 2001, 7, 4811.
[267] D. Touchard, P. Haquette, A. Daridor, L. Toupet, P. H. Dixneuf,
J. Am. Chem. Soc. 1994, 116, 11 157.
[268] A. FMrstner, O. R. Thiel, L. Ackermann, H.-J. Schanz, S. P.
Nolan, J. Org. Chem. 2000, 65, 2204.
[269] A. FMrstner, F. Jeanjean, P. Razon, Angew. Chem. 2002, 114,
2203; Angew. Chem. Int. Ed. 2002, 41, 2097.
[270] A. FMrstner, W. Leitner, Angew. Chem. 2003, 115, 320; Angew.
Chem. Int. Ed. 2003, 42, 308.
[271] A. FMrstner, O. R. Thiel, J. Org. Chem. 2000, 65, 1738.
[272] A. FMrstner, T. MMller, J. Am. Chem. Soc. 1999, 121, 7814.
[273] A. FMrstner, K. Radkowski, C. Wirtz, R. Goddard, C. W.
Lehmann, R. Mynott, J. Am. Chem. Soc. 2002, 124, 7061.
[274] B. Scheiper, F. Glorius, A. Leitner, A. FMrstner, Proc. Natl.
Acad. Sci. USA 2004, 101, 11 960.
[275] P. Davoli, A. Spaggiari, L. Castagnetti, F. Prati, Org. Biomol.
Chem. 2004, 2, 38.
[276] E. Diez, D. J. Dixon, S. V. Ley, A. Polara, F. Rodriguez, Helv.
Chim. Acta 2003, 86, 3717.
[277] E. P. KMndig, A. Bellido, K. P. Kaliappan, A. R. Pape, S. Radix,
Synlett 2003, 2407.
[278] S. Jung, C. D. Brandt, H. Werner, New J. Chem. 2001, 25, 1101.
[279] P. Le Gendre, M. Picquet, P. Richard, C. Moise, J. Organomet.
Chem. 2002, 643–644, 231.
[280] I. Tzdemir, E. Cetinkaya, B. Cetinkaya, M. Cicek, D. SRmeril,
C. Bruneau, P. H. Dixneuf, Eur. J. Inorg. Chem. 2004, 418.
[281] M. Bassetti, F. Centola, D. SRmeril, C. Bruneau, P. H. Dixneuf,
Organometallics 2003, 22, 4459.
[282] P. Dounis, W. J. Feast, A. M. Kenwright, Polymer 1995, 36,
2787.
[283] R. R. Schrock, K. B. Yap, D. C. Yang, H. Sitzmann, L. R. Sita,
G. C. Bazan, Macromolecules 1989, 22, 3191.
[284] M. Picquet, I. Tkatchenko, I. Tommasi, P. Wasserscheid, J.
Zimmermann, Adv. Synth. Catal. 2003, 345, 959.
[285] M. Saoud, A. Romerosa, M. Peruzzini, Organometallics 2000,
19, 4005.
[286] R. Akiyama, S. Kobayashi, Angew. Chem. 2002, 114, 2714;
Angew. Chem. Int. Ed. 2002, 41, 2602.
[287] P. Wasserscheid, W. Keim, Angew. Chem. 2000, 112, 3926;
Angew. Chem. Int. Ed. 2000, 39, 3772.
[288] H. Olivier-Bourbigou, L. Magna, J. Mol. Catal. A 2002, 182/183,
419.
[289] T. Welton, Coord. Chem. Rev. 2004, 248, 2459.
[290] D. SRmeril, H. Olivier-Bourbigou, C. Bruneau, P. H. Dixneuf,
Chem. Commun. 2002, 146.
[291] S. Csihony, C. Fischmeister, C. Bruneau, I. T. Horvath, P. H.
Dixneuf, New J. Chem. 2002, 26, 1667.
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
2203
Документ
Категория
Без категории
Просмотров
19
Размер файла
779 Кб
Теги
vinylidene, metathesis, application, metali, alkynes, catalysing, additional, terminal, anti, alkenes, allenylidene, markovnikov
1/--страниц
Пожаловаться на содержимое документа