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Transition Metal Arene -Complexes in Organic Synthesis and Catalysis. (Series Topics in Organometallic Chemistry Vol. 7.). Edited by E

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Angewandte
Chemie
example would have illustrated the topic
better, especially for biochemists. In
addition, a noticeable lack of up-todate references limits the inspirational
power of these two last chapters.
In summary, I believe that this book
has great merits and can be read with
profit by both electrochemists and biologists (and also by biochemists and biophysicists). The different subjects are
treated very clearly and with sufficient
details to appeal to graduate students
and researchers. All the chapters are
written using the same terminology,
and there are frequent and adequate
cross-references
between
them.
Although this book actually brings a
common base to electrochemists and
biologists, it might be criticized as failing
to sufficiently highlight current opportunities for interdisciplinary collaboration.
If regarded as an independent work, the
book lacks a few important chapters on
membrane proteins and applications.
Some of this information can be found
in other volumes of the series, but then
the purchase is practically restricted to
scientific libraries.
Samuel Terrettaz
Institute of Physical Chemistry
EPFL, Lausanne (Switzerland)
Transition Metal Arene pComplexes in Organic Synthesis
and Catalysis
(Series: Topics in
Organometallic
Chemistry, Vol. 7.).
Edited by E. Peter
Kndig. Springer
Verlag, Heidelberg
2004. 232 pp.,
hardcover
E 199.95.—ISBN
3-540-01604-X
This volume on the applications of arene
p-complexes in organic synthesis and
catalysis, which belongs to the series
Angew. Chem. Int. Ed. 2005, 44, 1590 – 1592
Topics in Organometallic Chemistry, is
edited by E. Peter Kndig, who has a
high reputation in the field. He is also
the author of two of the contributions.
The editor has succeeded well in the
selection of authors, who have particularly strong profiles in their respective
areas of research. Therefore, the book
offers the reader considerable promise.
After a concise introduction, E. P.
Kndig reviews the synthesis of h6
arene complexes in the first chapter. In
accordance with their importance, the
synthesis of tricarbonylchromium complexes is treated more extensively, followed by that of molybdenum complexes and cationic complexes of manganese, iron, and ruthenium. For each
of the metals, the standard procedures
for the synthesis of the complexes are
described, followed by a discussion of
their decomplexation possibilities. This
is particularly valuable, as the organic
chemist using transition metal complexes in synthesis is usually mainly
interested in the metal-free final product of the synthesis. As the chapter
also mentions the limitations of the
respective procedures, such as the possible presence of stoichiometric amounts
of Lewis acids in the formation of [(arene)FeCp]+ complexes, the chemist can
easily decide whether or not the procedure is of interest for the purpose in
hand.
In the second chapter, M. F. Semmelhack and A. Chelenov summarize
research directed to the lithiation of
(arene)tricarbonylchromium complexes
and subsequent reactions with electrophiles. The formation of aryllithium
complexes is discussed, and is followed
by their trapping by electrophiles.
Next, ortho-lithiation reactions and subsequent intramolecular substitution are
described. The issue of regioselectivity
in the deprotonation of (arene)tricarbonylchromium complexes is discussed in
more detail; the authors present the
material in a competent way, avoiding
lengthy redundancies. However, some
minor inaccuracies have slipped in. In
the section about metal–metal exchange
reactions, the authors write about the
retention of stereochemistry, whereas
they clearly mean that of configuration.
In the section about ortho metalation
followed by intramolecular substitution,
the description of the reaction of (fluowww.angewandte.org
robenzene)tricarbonylchromium with
butyllithium leading to g-butyrolactone
appears to show an unintended inversion of the absolute configuration. In
the discussion of the methylation of tricarbonyl(naphthalene)chromium using
LDA/MeI, carbon atoms C-1 and C-2
appear to have been interchanged.
The third chapter is written by the
same authors, and features nucleophilic
substitution reactions in (arene)tricarbonylchromium complexes. The two
sections of the chapter review substitution of heteroatoms and (formal) substitution of hydrogen. The first section is
dominated by haloarene tricarbonylchromium complexes. It goes beyond
the subject indicated in the title of the
section, by also discussing arene complexes with cationic cyclopentadienyliron, cyclopentadienylruthenium, tricarbonylmanganese, and cyclopentadienyl(ethyl)rhodium. A differentiation
between hetero and carbon nucleophiles
is made, and some aspects of cine and
tele substitutions are discussed. The predominance of tricarbonylchromium
complexes in this field is explained by
their facile decomplexation. This
aspect becomes more evident in the
second section, which discusses the substitution of hydrogen atoms of the aromatic ligand. Clearly, questions of regioselectivity are more important here, and
they are adequately discussed. Unfortunately, the last formula of the chapter
contains a mistake: the ligand is a derivative of biphenylene, not of benzocyclobutene.
A particularly important aspect of
the chemistry of arene complexes, the
de-aromatization of the ligands, is discussed very competently by E. P.
Kndig and A. Pape in the fourth chapter. By addition of carbon nucleophiles
followed by electrophiles—protonation
through addition of carbon electrophiles—one obtains, diastereoselectively, substituted cyclohexadienes that
are very useful for synthetic purposes
and are enantiomerically pure in many
cases. Whereas the use of reactions
starting from the corresponding molybdenum complexes is still in its infancy,
the authors review a number of publications reporting the use of cationic manganese complexes for such reactions,
thus nicely complementing the chemistry of the chromium complexes.
2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1591
Books
The next chapter, in which W. D.
Harman reviews the chemistry of h2coordinated arenes with electron-delivering metal fragments, is particularly
interesting. Here, pentaammineosmium
complexes are the focus of interest.
Their importance results from the fact
that the well-established chemistry of
(arene)tricarbonylchromium complexes
is complemented by facilitating an electrophilic attack at the two uncoordinated double bonds. For example, a
coordinated phenol reacts with the
uncoordinated double bonds just like a
dienol: the nucleophilic C-4 is able to
attack the b carbon atom of an a,b-unsaturated carbonyl compound in a
Michael addition. Thereby the phenol
becomes a coordinated cyclohexadienone, which finally, after re-aromatization and decomplexation, results in a
phenol with a substituent at C-4. This
chemistry offers various possibilities,
including the use of anilines, intramolecular variants, cyclization reactions, and
additions to unfunctionalized aromatic
substrates, as well as stereoselective
reactions. The chemistry described here
is quite different from the contents of
all of the other chapters, and summarizes the developments of the last 15
years.
M. Uemura, one of the most competent chemists in the field of (arene)tricarbonylchromium complexes, reviews
the most important aspects of cyclization, cycloaddition, and cross-coupling
reactions. After a brief overview about
cyclization reactions of benzylic anions
and cations, he reports recent results
concerning free-radical cyclizations.
Most of these reactions rely on the use
of samarium diiodide. The most important aspect of cycloadditions involving
coordinated benzaldehyde, benzaldimines, and styrenes is the translation
of planar chirality of unsymmetrically
substituted arene complexes into stereo-
1592
genic centers of the respective cycloadducts. The discussion covers both the
thermal and the low-temperature oxyanion-driven ring opening of benzocyclobutene complexes to give coordinated ortho-quinodimethanes followed
by cycloaddition, as well as the dianionic
oxy-Cope rearrangement that results
from alkenyllithium diaddition to the
tricarbonylchromium complex of benzocyclobutenedione. Palladium-catalyzed
coupling reactions, usually starting
from chlorobenzene complexes, are discussed somewhat more extensively.
Heck, Sonogashira, and Suzuki–
Miyaura coupling reactions are tools
for the stereoselective synthesis of
highly functionalized coupling products,
with particular emphasis on the asymmetric synthesis of chiral biaryls, which
had been developed by the author himself. As in some of the other chapters,
only a few references more recent than
2000 are cited.
The significance of arene complexes
in the stereoselective synthesis of natural products becomes particularly clear
in the following chapter by H.-G.
Schmalz. Selected syntheses of sesquiterpenes, diterpenes, alkaloids, and
interesting biaryls with axial chirality
serve to highlight the potential of
planar chiral (arene)tricarbonylchromium complexes in a very skillful and
convincing way. Some duplication
occurs with the synthesis of ( )-steganone as described by M. Uemura,
which has already appeared in the preceding chapter. However, here it is contrasted with the discussion given by G.
Molander.
Arene complexes as catalysts is the
topic of the following chapter by J. H.
Rigby and M. A. Kondratenko. The
authors distinguish between catalyses
involving a dissociation of the arene
ligand and those with retention of the
arene–metal bond. In the first part, a
2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
number of catalyses are presented. It
becomes clear to the reader that the
importance of arene complexes in this
area is still somewhat limited, and is
restricted to a number of single examples. The second part is dominated by
arene–ruthenium complexes, which
have gained some importance as catalysts in asymmetric transfer hydrogenation reactions. On the whole, the chapter
reads more like a systematic list of reactions, and does not offer any comparison
with alternative catalysts for the reactions discussed.
In the last, more forward-looking
chapter of the book, K. Muiz reviews
applications of planar chiral (arene)tricarbonylchromium complexes as ligands
for asymmetric catalysis. The chapter is
competently written, and includes a
number of asymmetric catalyses such
as Diels–Alder cycloadditions and
hydrovinylation reactions. The catalysts
have some similarity with related ferrocene-based catalysts, and usually contain, in addition to their planar chirality,
a center of chirality. To evaluate the
effect of the planar chirality, the reader
would like more comparison with the
catalytic activity of the chiral, but
uncomplexed, ligands.
Overall, this is an excellent book
with a lot of valuable, concisely presented information. The literature references usually end with the year 2001.
Occasional language shortcomings, or
formulas that are printed too small,
cannot significantly detract from the
high quality of the contributions.
Holger Butenschn
Institut fr Organische Chemie
Universitt Hannover (Germany)
DOI: 10.1002/anie.200485231
Angew. Chem. Int. Ed. 2005, 44, 1590 – 1592
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