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Organometallic Variants of the Wittig Reaction Synthesis and Structure of trans--(2Ц5; 8Ц11--Dodecapentaene)bis(tricarbonyliron).

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The I3C-NMR spectrum of the resulting solution exhibited twelve major absorptions (Table 1). Based on the
chemical shifts and multiplicities the ion is unequivocally
assigned the dicationic structure 2. The dication has a bishomoaromatic/allylic dication framework, and the observed chemical shifts correspond closely to those of the
monocations 3f3=Iand 4[3b1;
however, the bishomoaromatic
moiety in 2 is unsymmetrical. The observed 'H-NMR
spectrum i s also compatible with structure 2 (Table 1). 2 is
stable only below -100°C; at higher temperatures it
slowly rearranges irreversibly to a new species.
CH3
CH3
2
5
\
CH3
CH3
FH3
6
7
&
A
3
CH3
8
Warming a solution of 2 to -40°C results in formation
of a species with only six absorptions in the 13C-NMR
spectrum, indicating the formation of a very symmetrical
dicationic system. The observed chemical shifts and multiplicities suggest formation of a tertiary bisallylic dication.
The 'H-NMR chemical shifts in the allylic region at
6=9.25 and 8.12 also corroborate this structure. The rearrangement of the unsymmetrical dication 2 to a symmetrical new dicationic system can occur via a 1,3-sigmatropic
shift. In fact, a 1,3-shift of either the C6-C7 bond or the
C'-C2 bond results in two symmetrical bisallylic tertiary
dicationic systems 5 or 7.The structure of the rearranged
species is unequivocally assigned to the cis-anti-cis-3,lO-dimethyltricyclo[5.3.0.02~6]deca-4,8-dien-3,10-diyl
dication 5 :
formation of cis-anti-anti-dication 7 was excluded by its
independent synthesis involving ionization of the 3,8-diol
6c41in FS03H/S02C1F at -78°C. It appears that the
C6-C7 bond migrates preferentially since it is farther from
the tertiary allylic cationic center than the C'-C2 bond.
There is precedence for similar rearrangements in the literature: the 7-norbornadienyl cation 8 undergoes rapid 1,2sigmatropic shift (through the intermediacy of bicycl0[3.2.0]heptadienyl cation 9), resulting in scrambling of
carbon and hydrogen atomscsa1.The photochemical conversion of tricyclic diendione 10 into cis-anti-cis-tricyclic
dienedione 11 has also been reported[5b1,although we were
unable to reproduce this result satisfactorily.
Dications 5 and 7 show similar I3C-NMR chemical
shifts, although there are some apparent differences in the
Table 1. "C- and 'H-NMR spectroscopic data of the tricyclic carbodications
2, 5, and 7 [a].
Dication
6(I3C)
WH)
2
263.6 (C-3), 220.5 (C-5), 152.1
(C-4), 132.9 (C-9), 131.5 (C-8),
89.4 (C-lo), 63.2 (C-2), 60.5
(C-6), 58.6 (C-I), 52.3 (C-7),
30.5 (3-CH3), 13.2 (IO-CHs)
256.4 (C-3,10), 207.2 (C-5,8),
156.8 (C-4,9), 58.6 (C-1,2),
55.6 (C-6,7), 28.7 (CH3)
261.00 (C-3,8), 217.1 (C-5,10),
151.7 (C-4,9), 57.3 (C-2,7),
54.4 (C-1,6), 28.4 (CH3)
9.8 (d, J=5.0 Hz, H-5), 7.82
(d, J=5.0 Hz, H-4), 7.16 (br.,
H-8,9), 5.02 (br., H-2,6), 4.58
(m, br., H-l,7), 3.37 (s, 3CHI), 2.13 (s, 10-CH,)
9.25 (d, J=4.7 Hz, H-5,8),
8.12 (m, br., H-4,9), 5.46 (m,
H-1,2,6,7), 3.35 (s, CH3)
~~~
5
7
[a] Chemical shifts relative to ext. tetramethylsilane
Angew. Chem. Inr. Ed. Engl. 22 (1983) No. 9
9
8
QQ0
0
10
11
chemical shifts of the allylic carbon atoms. This is as a
consequence of the separation of the tertiary cationic centers by only two C atoms in 5 , compared to three C atoms
in 7.
Received: April 6, 1983 [Z 333 IE]
German version: Angew. Chem. 95 (1983) 726
[I] Review: G. K. S. Prakash, T. N. Rawdah, G. A. Olah, Angew. Chem. 95
(1983) 356; Angew. Chem. I n f . Ed. Engl. 22 (1983) 390.
[2] The diol was prepared by the addition of methyllithium to the endo-tricyclo[5.2.1.02~6]deca-4,8-diene-3,10-dione
in diethyl ether.
[3] a) G. A. Olah, G. Liang, J. Am. Chem. Soc. 97 (1975) 6803; b) G. A. Olah,
G. K. S. Prakash, G. Liang, J. Org. Chem. 41 (1976) 2820.
[4] The diol was prepared by the addition of methyllithium to cis-anfi-anfitricycl0[5.3.0.0~~~~deca-4,9-diene-3,8djone.
The dienedione was prepared
from cyclopentenone in five steps following the procedure of P. E. Eaton
(J. Am. Chem. SOC.84 (1962) 2344). Attempts to prepare the cis-anfi-cisdiendione 11 by a similar procedure were, however, unsuccessful.
151 a) R. K. Lustgarten, M. Brookhart, S . Winstein, J. Am. Chem. Soc. 89
(1967) 6350; b) U. Klinsmann, J. Gauthier, K. Schaffner, M. Pasternak, B.
Fuchs, Helv. Chim. Acta 55 (1972) 2643.
Organometallic Variants of the Wittig Reaction:
Synthesis and Structure of trans-p-(2-5 ;8-111Dodecapentaene)bis(tricarbonyliron)**
By Andreas Hafner, Jost H. Bieri, Roland Prewo,
Wolfgang von Philipsborn, and Albrecht Salzer*
Cationic metal complexes of type 1 react readily with
nucleophiles, which generally attack the dienyi system at
the terminal carbon atom and approach from the anti-side.
The synthetic potential of this reaction has been exploited"'. Using tertiary phosphanes, metal-coordinated
[*I Priv.-Doz. Dr. A. Salzer
Anorganisch-chemisches Institut der Universitgt
Winterthurerstrasse 190, CH-8057 Zurich (Switzerland)
Prof. Dr. W. von Philipsborn, A. Hafner, Dr. J. H. Bieri, R. Prewo
Organisch-chemisches Institut der Universitat Zurich
[**I Reactions with Metal-Coordinated Olefins, Part 2.-Part 1: [2b].
0 Verlag Chemie GmbH, 6940 Weinheim. 1983
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713
phosphonium derivatives of type 2['"], which are hardly accessible by other routes, are formed quantitatively.
Q
@>
2
Fe(~o),
They can be oxidatively decomplexed[2b1;2 itself cannot
be converted into a stable ylide""'. This occurs only when
dimethyl(pheny1)phosphane is usedf2''.
Our investigations now indicate that reaction of acyclic
dienyl systems such as 4['] with triphenylphosphane and
subsequent deprotonation with n-butyllithium lead to formation of stable deep-red solutions of ylide complex 6,
which smoothly undergo a Wittig reaction with 3I3]to form
the two isomeric polyene complexes 7a and 7b in the ratio
1 :3'4'.
Fig. 1. Molecular structure of complex 7a in the crystal. Structural data (at
ca. - 140 "C): P2,/c; a =7.389(1),6 = 12.230(1),c= 11.923(1) p = 117.83(1)",
2 = 2 ; 3448 symmetry-independent reflections: (sin8)M < 0.76 k';
R = 0.036, no absorption correction. Further details on the crystal structure
investigation can be obtained from the Fachinformationszentrum Energie
Physik Mathematik, D-75 14 Eggenstein-Leopoldshafen by quoting the depository number CSD 50485, the names of the authors, and the journal citation.
A,
1) NaBH4
2) HBF4
3
7a,b
a
BuL,
1
5
3ph,c
THF/-7B0C
Fe(C0)j
(OC),Fe PPh,
Q
6
The products 7a and 7b have the empirical formula
C12H16Fe2(C0)6;their I3C-NMR spectra are consistent
with symmetrical structures with four coordinated and one
non-coordinated double bond[41.Because of the symmetry
and the fixed (E,E)-configuration of 3,they can, therefore,
only differ in configuration at C-6, C-6'. On the basis of
the coupling 3J(C-5, HC-69, obtained from selectively
('HI-decoupled I3C-INEPT spectra, we assign an (a-configuration to 7a and, in contrast, a (2)-configuration to 7b
for the middle double bond.
'
7b
Both molecules have two (degenerate) chiral moieties ;
they therefore occur as an enantiomeric pair or as a mesoform. No stereochemical assignment can be made from the
spectroscopic data of 7a and 7b; however, it appears that
both molecules most probably have a trunsoid arrangement
of the two Fe(CO)3 groups. This is confirmed for 7a by Xray structure analysis (Fig. 1). The polyene chain is almost
planar, but exhibits the usual slight distorsion of the terminal CC bonds of complexed s-cis-dienes.
Compounds 7a and 7b are, on the whole, air-stable and
even at higher temperatures are configurationally stable.
714
0 Verlag Chemie GmbH, 6940 Weinheim, 1983
They are moderately soluble in aliphatic solvents, but
readily soluble in toluene or CHCI,. Deprotonation of 5
with potassium tert-butoxide affords 7a, exclusively, just
as in the Wittig-Homer variant, which upon reaction of 4
with trimethyl phosphite and subsequent spontaneous Michaelis-Axbuzov reaction of the primary adduct leads to
8.
The Wittig carbonyl olefination is a key reaction in preparative organic polyene chemistryr5".bl, but is also occasionally used to extend the chain length of diene-Fe(C0)3
complexes[5ci.The reactions described here differ from
conventional methods in three ways:
1. The reaction of cationic dienyl-Fe(CO), complexes with
triphenylphosphane or trimethylphosphite affords in regeiospecific addition otherwise only difficultly accessible dienylphosphonium salts or dienylphosphonates.
2. The cisoid-ylides formed initially upon deprotonation of
5 or 8 are apparently unstable; they isomerize completely at C-2. In fact, 5 rearranges to the isomeric
(E,E)-phosphonium complex with deuteration at C-1 in
the presence of catalytic amounts of CD30Na in
CD30DLZb1.
Cyclic systems such as 2 do not have this
stabilization possibility and cannot, therefore, be converted into stable ylides at the complex.
3. Formation of the ylide from 5 using nBuLi and subsequent reaction with 3 do not lead to the high (a-selectivity normally observed, but to the preferred formation
of the (Z)-isomer. Use of tBuOK as described by
S c h Z o s ~ e r [in
~ ~turn
~ , unexpectedly affords exclusively
the (E)-isomer 7a. In contrast, the Wittig-Horner reaction displays the normal (E)-selectivitylsbl.
Received: April 28, 1983 [Z 364 I E ]
German version: Angew. Chem. 95 (1983) 736
[l] Cf. Nachr. Chem. Tech. Lab. 30 (1982) 706; A. J. Birch, I. D. Jenkins in H.
Alper: Transition Metal Organomelallics in Organic Synthesis, Vol. 1, Academic Press, New York 1976.
121 a) J. Evans, D. V. Howe, B. F. G. Johnson, J. Lewis, 3. Organomet. Chem.
61 (1973) C48; b) A. Hafner, A. Salzer, Helu. Chim. Acta. in press; c) G.
Jaouen, B. F. G. Johnson, J. Lewis, 3. Organomet. Chem. 231 (1982)
c21.
[3] Gmelin Handbook of Inorganic Chemistry, Organoiron Compounds, Part
B 6, Springer, Berlin 1981.
141 7a and 7b separated using Lobar chromatography: LiChroprep Si 60
(15-25 Gm), heptane. "C-NMR (25.2 MHz, 2 5 T , CDCI,, int. TMS,
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Angew. Chem. Int. Ed. Engl. 22 (1983) No. 9
proton noise decoupled): 7a : 6(CH,)= 19.2,6(C-2)= 57.0,6(C-3,4)= 80.8,
85.0,6(C-5)=62.1,6(C-6)= 132.4; 7b:6(CH3)= 19.3,6(C-2,5)=56.2, 57.5,
6(C-3,4)=82.4, 85.9, 6(C-6)= 131.7.
[5] a) H. Pommer, Angew. Chem. 89 (1977) 437; Angew. Chem. Int. Ed. Engi.
16 (1977) 423; b) H. J. Bestmann, Pure Appl. Chem. 51 (1979) 515; C)R. C.
Kerber in E. A. Koerner von Gustorf, F. W. Grevels, 1. Fischler: The Organic Chemistry of Iron, Vol. 2. Academic Press, New York 1981, d) M.
Schlosser, K. F. Christmann, Liebigs Ann. Chem. 708 (1967) 1.
+
Inclusion Complexes between a Macrocyclic Host
Molecule and Aromatic Hydrocarbons in Aqueous
Solution
O=$-CHJ
fN7
By FranGois Diederich* and Klaus Dick
We are interested in cyclophane-like macrocycles which
possess a hydrophobic cavity of definite size and which
permit the formation of stoichiometric inclusion complexes with apolar substrates in aqueous solution at room
temperature at pH = 7IZ1.The key reaction in the synthesis
of the novel host molecule 1 is the cyclization of two equivalents each of 7 and 8 to the macrocycle 9, which proceeds in 18% yield; 1 is obtained in good yield after four
subsequent steps[31.Over the range 2 x 1OP4-7 x l o p 3M,
the 'H-NMR signals of 1 in D20 (303 K, see Table 1) are
independent of concentration and are highly resolved. The
critical micellar concentration (CMC) of 1 in water was
M by 'H-NMR spectroscopy.
found to be 7.5 x
If a suspension of solid pyrene prepared by ultrasonification is stirred or shaken with a 2 x lo-' M aqueous solution of 1 and then centrifuged and filtered, the solution exhibits the intense fluorescence of monomeric pyrene.
In this solid-liquid extraction an inclusion complex between pyrene and 1,which possesses a hydrophobic cavity
of complementary size, is formed. A solution of 13 (with
smaller cavity) is considerably less effective. A 2 x lo-' M
solution of y-cyclodextrin has an even weaker effect, and a
2x
M solution of 12 produces no increase in fluorescence intensity compared to the extraction with water.
Aqueous solutions of the complex of 1-pyrene can also
be prepared by liquid-liquid extraction: e.g. a ~ O - ' M solution of pyrene in n-heptane is shaken with a 2 x lo-' M aqueous solution of 1.
Multiple extraction of an aqueous solution of the l-pyrene complex with n-hexane results in quantitative transfer
of pyrene into the organic phase; the concentration of 1
before complex formation can be determined from the absorption spectrum of the aqueous phase. The concentration of the complex is obtained from the concentration of
pyrene in the organic phase on consideration of the solubility of pyrene in water'"]. Using a 5.5 x
M solution
of 1, a concentration of complex of 2 . 9 ~l O p 3 ~was
achieved.
Evidence for the 1 :I-stoichiometry and information
about the geometry of the 1-pyrene complex in aqueous
solution were obtained by 'H-NMR spectroscopy (Table
1). The large difference in chemical shift between the solution of the complex and the solutions of the components
can best be explained by the following favored geometry
of the complex: the long pyrene C2-axis through C(2) and
C(7) lies along the direction of the C2-axis passing through
the cavity of 1 perpendicular to the mean molecular plane.
[*] Dr. F. Diederich, K. Dick
Ahteilung Organische Chemie
Max-Planck-Institut fur Medizinische Forschung
Jahnstrasse 29, D-6900 Heidelberg I (Germany)
Angew. Chem. Inr. Ed. Engl. 22 (1983) No. 9
R
2H3C-C
H3C-
A : KOH, [18]crown-6, tetrahydrofuran, 48 h, 65"C, 18%; E : 1) NaOH,
CH30CH2CH20H, 124"C, 85%; 2) HCHO, HCOOH, IOOT, 91%; 3)
FS03CH3, CHCI,, 2 5 T , 82%; 4) Dowex 1 x 8 Cle, 79%.
Pyrene only then fits completely into the cavity if its short
Cz-axis, which intersects the C(4)-C(5) and C(9)-C( 10)
bonds, runs in the direction of the C2-axis of 1through the
spiro carbon atoms of the two diphenylmethane moieties.
In this way, H-2,7 of pyrene project out of the cavity and
are shifted to the smallest extent; in contrast, H-1,3,6,8 and
H-4,5,9,10 are directed towards the diphenylmethane
moieties and are shifted markedly to high field.
The proposed geometry for the complex is corroborated
by the low-field shift of the protons of 1 in the pyrene molecular plane and by the high-field shift of the protons perpendicular to this plane. The unexpected high-field shift of
H-2' and N(l?-CH3 can be explained by the conformational mobility of the Cs bridges bearing the piperidinium
0 Verlag Chemie GmbH, 6940 Weinheim, 1983
0570-0833/83/0909-0715 $02.50/0
715
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dodecapentaene, organometallic, 2ц5, structure, synthesis, 8ц11, reaction, tricarbonyliron, variant, wittig, bis, transp
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