Dihydropyridines in organometallic synthesis. Formation of pyridine and dihydropyridine-stabilized alkylidene complexes of tungsten(0) and chromium(0) from Fischer carbene complexes: Structure and reactivity

Article abstract of DOI:10.1021/ja9622057

1,2- and 1,4-dihydropyridines react with alkoxycarbene complexes of chromium and tungsten to give, upon an unprecedented hydride transfer, alcohol elimination, and pyridine fixation on the carbene carbon, a new class of air-stable pyridinium ylide complexes. These pyridine-protected alkylidene complexes of chromium(0) and tungsten(0) were fully characterized by X-ray crystallography. In the case of (CO)₅W=C(CH₃)(OEt) (5a), besides the pyridinium ylide complex (CO)₅W^--C(H)(CH₃)(pyridine)⁺ (7a), the dihydropyridinium complex (CO)₅W^-C(H)(CH₃)(2,5-dihydropyridine)⁺ (8a) was also isolated. The intermediate tungstate (CO)₅W^--C(H)(CH₃)(OEt)(CH₃NC₅H₅)⁺ could be easily obtained and characterized by using, as reducing agent, N-methyldihydropyridine. Whereas phenyl-substituted pyridinium complexes easily transferred the benzylidene moiety to alkenes, alkyl-substituted complexes appeared more reluctant to such a transfer: satisfactory results were observed in the case of nucleophilic olefins such as enol ethers. However, straightforward transfer of the tungsten(0) alkylidene group took place, even at room temperature, in the case of alkoxycarbene complexes tethered to alkenes, giving access, upon intramolecular cyclopropanation reactions, to polycyclic systems.

Full text of DOI:10.1021/ja9622057

J. Am. Chem. Soc. 1996, 118, 12045-12058
12045
Dihydropyridines in Organometallic Synthesis. Formation of
Pyridine and Dihydropyridine-Stabilized Alkylidene Complexes
of Tungsten(0) and Chromium(0) from Fischer Carbene
Complexes: Structure and Reactivity
Henri Rudler,* Max Audouin, Andre´e Parlier, Blanca Martin-Vaca,
Re´gis Goumont, Thomas Durand-Re´ville, and Jacqueline Vaissermann
Contribution from the Laboratoire de Synthe`se Organique et Organome´tallique URA 408 and
Laboratoire de Chimie des Me´taux de Transition URA 608, UniVersite´ Pierre et Marie Curie,
T44-45, 4 place Jussieu, 75252 Paris Cedex 5, France
ReceiVed June 28, 1996X
Abstract: 1,2- and 1,4-dihydropyridines react with alkoxycarbene complexes of chromium and tungsten to give,
upon an unprecedented hydride transfer, alcohol elimination, and pyridine fixation on the carbene carbon, a new
class of air-stable pyridinium ylide complexes. These pyridine-protected alkylidene complexes of chromium(0) and
tungsten(0) were fully characterized by X-ray crystallography. In the case of (CO)5WdC(CH3)(OEt) (5a), besides
the pyridinium ylide complex (CO)5W--C(H)(CH3)(pyridine)+ (7a), the dihydropyridinium complex (CO)5W--
C(H)(CH3)(2,5-dihydropyridine)+ (8a) was also isolated. The intermediate tungstate (CO)5W--C(H)(CH3)(OEt)(CH3-
NC5H5)+ could be easily obtained and characterized by using, as reducing agent, N-methyldihydropyridine. Whereas
phenyl-substituted pyridinium complexes easily transferred the benzylidene moiety to alkenes, alkyl-substituted
complexes appeared more reluctant to such a transfer: satisfactory results were observed in the case of nucleophilic
olefins such as enol ethers. However, straightforward transfer of the tungsten(0) alkylidene group took place, even
at room temperature, in the case of alkoxycarbene complexes tethered to alkenes, giving access, upon intramolecular
cyclopropanation reactions, to polycyclic systems.
Introduction
Scheme 1
Whereas methylene transfer had been observed by Fischer
and co-workers as early as 1972 during the interaction of
heteroatom-substituted carbene complexes with R,â-unsaturated
esters and vinyl ethers,1 the first alkylidene complex which
mimicked both the metathesis and the cyclopropanation reactions
of linear and cyclic olefins in a way consistent with the
mechanistic proposal of Chauvin for these reactions was
described in 1973 by Casey and had structure 2 (Scheme 1).2-7
This tungsten(0) complex was obtained by successive treatment
of (CO)5WC(OEt)Ph (1) with phenyllithium and an acid at low
temperature and appeared to be less stable than its precursor 1.
A slightly modified method gave, later on, access to a series of
diarylcarbene complexes of chromium and tungsten.8 Attempts
to synthesize and isolate other simple metal(0) alkylidene
complexes of this type either failed due to fast â-elimination
reactions or led to unexpected dinuclear complexes (Scheme
2).9-11 However, a benzylidene complex, 3, of W(0) (and later
Scheme 2
X Abstract published in AdVance ACS Abstracts, November 1, 1996.
(1) Do¨tz, K. H.; Fischer, E. O. Chem. Ber. 1972, 105, 1356 and 3966.
(2) Casey, C. P.; Burkhardt, T. J. J. Am. Chem. Soc. 1973, 95, 5833.
(3) Casey, C. P.; Burkhardt, T. J. J. Am. Chem. Soc. 1974, 96, 7808.
(4) Herrisson, J. L.; Chauvin, Y. Makromol. Chem. 1970, 141, 161.
(5) Soufflet, J. P.; Commereuc, D.; Chauvin, Y. C.R. Acad. Sci., Ser. C
1973, 276, 169.
(6) Casey, C. P.; Tuinstra, H. E.; Saeman, M. C. J. Am. Chem. Soc.
1976, 98, 608.
(7) Levisalles, J.; Rudler, H.; Villemin, D.; Daran, J. C.; Jeannin, Y.;
Martin, L. J. Organomet. Chem. 1978, 155, C-1.
(8) Fischer, E. O.; Held, W.; Kreissl, F. R.; Frank, A.; Huttner, G. Chem.
Ber. 1977, 110, 656.
(9) Casey, C. P.; Albin, L. D.; Burkhardt, T. J. J. Am. Chem. Soc. 1977,
99, 2533.
(10) Fischer, E. O.; Held, W. J. Organomet. Chem. 1976, 112, C59.
(11) Levisalles, J.; Rudler, H.; Jeannin, Y.; Dahan, F. J. Organomet.
Chem. 1979, 178, C-8.
of Cr(0)) could be prepared in a two-step process by reacting
successively (CO)5WC(OEt)Ph (1) with a complex hydride,
KHB(OiPr)3, and an acid.12-17 Due to its unstability, complex
(12) Casey, C. P.; Polichnowsky, S. W. J. Am. Chem. Soc. 1977, 99,
6097.
(13) Casey, C. P.; Polichnowsky, S. W.; Shusterman, A. J.; Jones, C. R.
J. Am. Chem. Soc. 1979, 101, 7282.
(14) Fischer, H.; Zeuner, S.; Ackermann, K. J. Chem. Soc., Chem.
Commun. 1984, 684.
(15) Fischer, H.; Bidell, W.; Hofmann, J. J. Chem. Soc., Chem. Commun.
1990, 858.
S0002-7863(96)02205-6 CCC: $12.00 © 1996 American Chemical Society

12046 J. Am. Chem. Soc., Vol. 118, No. 48, 1996
Rudler et al.
3 could only be handled at low temperature (-80 to -20 °C).
Its reaction with phosphines led however to stable phosphorus
ylides 4a,b. Whereas 2 reacted with olefins to give both
metathesis and cyclopropanation products, complex 3 only led
to phenylcyclopropanes.
few minutes complete consumption of the starting material and
formation of two new complexes were observed. The faster
moving yellow complex was assigned as structure 6a on the
grounds of its elemental analysis and its spectroscopic data. The
1H NMR spectrum showed signals for only five aromatic protons
of the pyridine ring system slightly shifted with respect to those
of free pyridine (at δ 8.83 for 2H, 7.79 for 1H, and 7.28 for 2H
vs δ 8.60, 7.64, and 7.64 ppm). Both the infrared and the 13C
NMR spectra confirmed the presence of the (pentacarbonyl)-
tungsten(0) group (ν(CO) 2060, 1970, and 1930 cm-1; δ(CO)
202.35 and 199.47 ppm).
During the course of our investigations on the insertion of
alkynes into aminocarbene complexes of chromium, tungsten,
and molybdenum,18-20 we were led to study, for the synthesis
of the starting aminocarbene complexes, the aminolysis of
alkoxycarbene complexes of these metals with inter alia
unsaturated amines (Scheme 3). In the general case, no
1
The most striking feature of the H NMR spectrum of the
more polar complex 7a, isolated in 66% yield as an orange solid,
was the absence of signals due to the alkoxy group of the starting
complex, an observation which confirmed that indeed a
substitution reaction took place. However, no signals due to
the protons of dihydropyridine were observed. Instead, signals
due to the pyridine ring system were again present at δ 8.56
(2H, d), 7.85 (1H, t), and 7.63 (2H, t) ppm, thus only slightly
different from the signals of free pyridine (Figure 1). Moreover,
two signals for one proton at δ 4.91 ppm as a quartet and at δ
2.37 ppm for three protons as a doublet were attributable to a
CHMe group. Confirmation of this and of the presence of a
W(CO)5 group was again obtained by infrared and 13C NMR
spectroscopies, with signals at δ 57.1 and 30.7 ppm giving,
respectively, a doublet and a quartet in the off-resonance mode.
Thus, hydride transfer from dihydropyridine to the carbene
carbon with elimination of ethanol, together with addition of
pyridine to the complex, took place. A similar result was
observed starting instead from pure 1,2-dihydropyridine.
X-ray Structure of (CO)5WC(H)Me(pyridine) (7a). The
structure of this new complex was ascertained by an X-ray
crystallographic study and appears in Figure 2 where the atom
numbering scheme is also defined. The bond lengths (Å) and
bond angles (deg) for this complex are presented in Tables 1
and 2. Structure 7a consists of the pyridinium ylide of
ethylidene and five CO ligands octahedrally coordinated to
tungsten, the organic ligand being perpendicular to the plane
defined by the equatorial carbonyl groups. The ethyl carbon-
(1)-tungsten bond length of 7a is 2.32(2) Å, thus longer than
the 2.28(1) Å benzilic carbon-metal single bond in Cp2W(CH2-
Scheme 3
problems were expected and indeed encountered during these
attempts. However, in the special case of dihydropyridines, the
reducing properties of which are well known both in biological
systems and in classical organic chemistry,21,22 no substitution
of the alkoxy group by the amine took place. Instead, a new
reaction linked to these reducing properties led to pyridine23
and dihydropyridine-stabilized alkylidene complexes. The
purpose of this paper is to describe on the one hand the
interaction of a series of dihydropyridines with various alkoxy-
carbene complexes of tungsten and chromium, demonstrating
the general scope of the reaction. On the other hand, the
possible use of these complexes as stable cyclopropanation
reagents and of the aforementioned reduction reaction for the
direct intramolecular cyclopropanation reaction of alkene-
alkoxycarbene complexes will be outlined.
Results and Discussion
25
Ar)2 but similar to the 2.34(1) Å carbon-metal bond in
(CO)5W--CH(Ph)(OMe)N(CH2CH3)4+, the addition product of
a hydride to complex 1.26 The angle between the axis of the
pyridine ring and the axis of the W-C(1)-N(1) plane is equal
to 161°, the methyl group being 0.63 Å beneath this latter plane.
The geometry around C(1) corresponds to that of a deformed
sp3 hybridized carbon.
Synthesis and Structure of Methyl-Substituted Pyridinium
and Dihydropyridinium Ylide Complexes. When a yellow
ethereal solution of (CO)5WC(OEt)CH3 (5a) was treated at 0
°C with a freshly prepared solution of pure 1,4-dihydropyridine
in diethyl ether,24 a deep-red color developed rapidly. After a
(16) Fischer, H.; Hofmann, J. Chem. Ber. 1991, 124, 981.
(17) Fischer, H.; Mauz, E.; Jaeger, M. J. Organomet. Chem. 1992, 427,
63.
(18) Chelain, E.; Goumont, R.; Hamon, L.; Parlier, A.; Rudler, M.;
Rudler, H.; Daran, J. C.; Vaissermann, J. J. Am. Chem. Soc. 1992, 114,
8088.
X-ray Structure of (CO)5WC(H)Me(2,5-dihydropyridine)
(8a). When however an excess of a mixture of 1,2- and 1,4-
dihydropyridines was used (as obtained by sodium borohydride
reduction of N-(methoxycarbonyl)pyridinium chloride),24
a
(19) Chelain, E.; Parlier, A.; Audouin, M.; Rudler, H.; Daran, J. C.;
Vaissermann, J. J. Am. Chem. Soc. 1993, 115, 10568.
(20) Rudler, H.; Audouin, M.; Chelain, E.; Denise, B.; Goumont, R.;
Massoud, A.; Parlier, A.; Pacreau, A.; Rudler, M.; Yefsah, R.; Alvarez, C.;
Delgado-Reyes, F. Chem. Soc. ReV. 1991, 503.
second complex, 8a, slightly less polar than 7a, could be
(21) Stout, D. M.; Meyers, A. I. Chem. ReV. 1982, 82, 223.
(22) Sausins, A.; Duburs, G. Heterocycles 1988, 27, 291.
(23) Cohen, F.; Goumont, R.; Rudler, H.; Daran, J. C.; Toscano, R. A.
J. Organomet. Chem. 1992, 431, C-6.
(25) Forder, R. A.; Jefferson, I. W.; Prout, K. Acta Crystallogr., Sect. B
1975, 31, 618.
(24) Fowler, W. F. J. Org. Chem. 1972, 37, 1321.

Dihydropyridines in Organometallic Synthesis
J. Am. Chem. Soc., Vol. 118, No. 48, 1996 12047
Figure 1. 1H NMR spectrum (CDCl3) of complex 7a.
Table 2. Bond Angles (deg) for Complex 7a
C(1)-W(1)-C(3)
C(3)-W(1)-C(4)
C(3)-W(1)-C(5)
C(1)-W(1)-C(6)
C(4)-W(1)-C(6)
C(1)-W(1)-C(7)
C(4)-W(1)-C(7)
C(6)-W(1)-C(7)
C(1)-N(1)-C(12)
W(1)-C(1)-N(1)
N(1)-C(1)-C(2)
W(1)-C(4)-O(4)
W(1)-C(6)-O(6)
N(1)-C(8)-C(9)
90.1(9)
C(1)-W(1)-C(4)
88.5(8)
88.8(9)
89.6(12)
91.0(10)
90.2(10)
90.4(9)
90.3(12) C(1)-W(1)-C(5)
178.8(8)
178.9(8)
91.1(8)
90.8(6)
C(4)-W(1)-C(5)
C(3)-W(1)-C(6)
C(5)-W(1)-C(6)
C(3)-W(1)-C(7)
179.0(10) C(5)-W(1)-C(7)
89.6(7) C(1)-N(1)-C(8)
117.4(15) C(8)-N(1)-C(12)
112.3(9) W(1)-C(1)-C(2)
116.3(16) W(1)-C(3)-O(3)
178.3(34) W(1)-C(5)-O(5)
178.7(20) W(1)-C(7)-O(7)
122.8(23) C(8)-C(9)-C(10)
89.7(9)
122.6(16)
119.6(16)
122.8(16)
178.6(22)
178.8(24)
178.9(19)
113.6(22)
C(9)-C(10)-C(11) 125.0(29) C(10)-C(11)-C(12) 118.0(27)
N(1)-C(12)-C(11) 120.7(20)
Figure 2. Perspective view and numbering scheme for (CO)5W--
C(H)(CH3)(C5H5N)+ (7a).
1
structure determination. The H NMR spectrum (Figure 3)
confirmed again the presence as for complex 7a of the CHMe
group with a multiplet at δ 3.80 and a doublet at δ 2.11 ppm
and the absence of the ethoxy group of the starting complex
5a. Moreover, signals for seven protons appeared at δ 7.81
(br s), 5.91 (m, 2H), 4.90 (dt, 1H), 4.18 (dt, 1H), and 3.20 (m,
2H) ppm, a set compatible with that expected for a dihydro-
pyridine. The observation of a broad singlet at low field agreed
with the presence of a proton linked to an imine -NdC(H)
function: thus, two methylene groups and a disubstituted double
bond had to complete the dihydropyridine frame. Extensive
irradiation experiments allowed the signals at δ 4.86, 4.17, and
3.20 ppm to be assigned to the two methylene groups and those
at δ 5.90 ppm to the olefinic protons.
Table 1. Bond Distances (Å) for Complex 7a
W(1)-C(1)
W(1)-C(4)
W(1)-C(6)
O(3)-C(3)
O(5)-C(5)
O(7)-C(7)
N(1)-C(8)
C(1)-C(2)
C(9)-C(10)
C(11)-C(12)
2.32(2)
2.02(2)
1.93(2)
1.14(2)
1.11(2)
1.13(2)
1.27(2)
1.35(3)
1.35(5)
1.36(3)
W(1)-C(3)
W(1)-C(5)
W(1)-C(7)
O(4)-C(4)
O(6)-C(6)
N(1)-C(1)
N(1)-C(12)
C(8)-C(9)
C(10)-C(11)
1.99(2)
2.05(2)
2.02(2)
1.12(2)
1.18(2)
1.49(2)
1.36(2)
1.43(4)
1.30(4)
detected by TLC. Careful silica gel chromatography of the
reaction mixture gave pure samples of this new complex which
upon recrystallization led to crystals suitable for an X-ray
The structure of this unexpected complex is shown in Figure
4, the bond distances (Å) and the bond angles (deg) being
gathered in Tables 3 and 4. It consists of the 2,5-dihydropy-
ridinium ylide of ethylidene coordinated to (pentacarbonyl)-
(26) Casey, C. P.; Polichnowsky, S. T.; Tuinstra, H. E.; Albin, L. D.;
Calabrese, J. C. Inorg. Chem. 1978, 17, 3045.

12048 J. Am. Chem. Soc., Vol. 118, No. 48, 1996
Rudler et al.
Figure 3. 1H NMR spectrum (CD2Cl2) of complex 8a.
Table 3. Bond Distances (Å) for Complex 8a
W(1)-C(1)
W(1)-C(4)
W(1)-C(6)
O(3)-C(3)
O(5)-C(5)
O(7)-C(7)
N(1)-C(8)
C(1)-C(2)
C(9)-C(10)
C(11)-C(12)
2.34(2)
2.01(2)
1.94(2)
1.17(3)
1.16(2)
1.18(2)
1.46(2)
1.48(2)
1.37(4)
1.44(3)
W(1)-C(3)
W(1)-C(5)
W(1)-C(7)
O(4)-C(4)
O(6)-C(6)
N(1)-C(1)
N(1)-C(12)
C(8)-C(9)
C(10)-C(11)
1.98(2)
1.99(2)
2.02(2)
1.18(2)
1.16(2)
1.54(2)
1.32(2)
1.52(3)
1.46(4)
Table 4. Bond Angles (deg) for Complex 8a
C(1)-W(1)-C(3)
C(3)-W(1)-C(4)
C(3)-W(1)-C(5)
C(1)-W(1)-C(6)
C(4)-W(1)-C(6)
C(1)-W(1)-C(7)
C(4)-W(1)-C(7)
C(6)-W(1)-C(7)
C(1)-N(1)-C(12)
W(1)-C(1)-N(1)
N(1)-C(1)-C(2)
W(1)-C(4)-O(4)
W(1)-C(6)-O(6)
N(1)-C(8)-C(9)
89.1(9)
C(1)-W(1)-C(4)
87.8(7)
91.5(8)
89.2(11)
91.5(10)
88.0(10)
88.4(10)
90.1(9)
110.3(15)
124.2(16)
116.6(13)
176.1(24)
177.3(23)
176.8(20)
117.3(24)
92.3(11) C(1)-W(1)-C(5)
178.4(8)
176.9(8)
89.1(9)
93.7(7)
178.3(9)
89.3(8)
C(4)-W(1)-C(5)
C(3)-W(1)-C(6)
C(5)-W(1)-C(6)
C(3)-W(1)-C(7)
C(5)-W(1)-C(7)
C(1)-N(1)-C(8)
Figure 4. Perspective view and numbering scheme for (CO)5W--
C(H)(CH3)(C5H7N)+ (8a).
124.3(16) C(8)-N(1)-C(12)
109.2(11) W(1)-C(1)-C(2)
109.2(16) W(1)-C(3)-O(3)
177.9(21) W(1)-C(5)-O(5)
177.8(23) W(1)-C(7)-O(7)
112.3(22) C(8)-C(9)-C(10)
tungsten(0). Both the geometry around C(1) and the bond
distances W-C(1) and C(1)-N(1) are very close to those
observed for complex 7a. The main difference is due to the
presence in complex 8a of two methylene groups in the R and
δ positions with respect to the nitrogen atom: whereas perfect
flatness is observed in the case of the pyridinium derivative 7a
(Figure 5a), a slightly twisted conformation of the dihydropy-
ridinium ring system appears in the projection shown in Figure
5b, the C(8) and C(11) methylene groups being slightly below
the N(1), C(9), C(10), C(11), and C(12) best plane. The bond
distances N(1)-C(8) (1.46(2) Å), C(8)-C(9) (1.52(3) Å),
C(12)-C(11) (1.44(3) Å), and C(11)-C(10) (1.46(4) Å) agree
with those of carbon-nitrogen and carbon-carbon single bonds
C(9)-C(10)-C(11) 125.1(24) C(10)-C(11)-C(12) 113.2(22)
N(1)-C(12)-C(11) 121.9(20)
whereas N(1)-C(12) (1.32(2) Å) and C(9)-C(10) (1.37(4) Å)
are compatible with carbon-nitrogen and carbon-carbon
double bonds. This is confirmed by the values of the bond
angles at C(8) (112.3(22)), C(9) (117.3(23)), C(10) (125.1(24)),
C(11) (113.2(22)), and C(12) (121.9(20)) and the sum of the
angles at N(1) (358.9°).

Dihydropyridines in Organometallic Synthesis
J. Am. Chem. Soc., Vol. 118, No. 48, 1996 12049
The 13C NMR spectrum confirmed structure 17: besides signals
for the CO groups and the various aromatic carbons, a signal
for the benzilic carbon is observed at δ 70.82 ppm. However,
the related chromium complex failed to lead to the expected
pyridinium ylide complex although it could be detected by
TLC: decomposition mainly into benzaldehyde took place
during attempts to purify it by silica gel chromatography.
Modifications of the Structure of the Dihydropyridines:
Formation of N-Methylpyridinium Tungstates from N-
Methylpyridine and Alkoxycarbene Complexes of Tungsten.
In order to determine the influence of substituents on the
dihydropyridine ring system, alkylated dihydropyridines28,29
were prepared by known procedures and used to reduce various
alkoxycarbene complexes. Thus, 2- and 4-methyldihydropy-
ridines led, both in the case of chromium and tungsten, besides
to the related pyridine (chromium or tungsten) pentacarbonyl
complexes 18a,b and 20b, to the expected pyridinium ylide
complexes 19a,b and 21b, yet in lower yields. No reaction was
Figure 5. Projections of the ethylidene pyridinium (a, top) and
dihydropyridinium (b, bottom) ylide fragments of complexes 7a
and 8a.
Reduction of the Chromium Complex (CO)5CrdC(OEt)-
Me (5b). The same reaction could be carried out on the
corresponding chromium complex 5b: however, only a 20%
yield of the reduction product 7b was obtained after silica gel
chromatography together with the corresponding known (py-
ridine)chromium pentacarbonyl complex (6b; 7.5%).27
Alkyl-Substituted Pyridinium Ylide Complexes of Tung-
sten. For synthetic purposes and in order to establish the scope
of the new reduction reaction of alkoxycarbene complexes, the
preparation of a series of alkyl-substituted pyridinium ylide
complexes was attempted. The starting alkoxycarbene com-
plexes of tungsten 9, 11, 13, and 15 were either known
complexes or were prepared from tungsten hexacarbonyl by the
use of classical methods. Their preparation and spectroscopic
data can be found in the experimental section.
however observed in the case of more hindered dihydropyri-
dines such as 2-phenyl- and 2,2-dimethyldihydropyridines.
Moreover, removal of the hydrogen atoms at C(4) by dimeth-
ylation30 completely inhibited the reaction: neither reduction
nor aminolysis of the starting alkoxycarbene complexes was
observed.
More interesting as far as the mechanism of the formation of
these new ylide complexes and their use in organic synthesis is
concerned was the reaction between complexes 1 and 5a with
N-methyldihydropyridine.24 Thus, when complex 1 was treated
These complexes reacted with dihydropyridine as in the
previous cases to give the corresponding pyridinium ylides 10,
12, 14, and 16 as orange air-stable solids. The spectroscopic
data were in all respects in agreement with these structures with
a typical chemical shift for all the carbons linked to the metal
at about 63 ppm and a multiplet for the hydrogen bound to this
carbon around 4.6 ppm.
Phenyl-Substituted Pyridinium Ylide Complexes. Under
the same conditions as for complexes 5, complex 1 led to a
mixture of complexes 6a and 17 in, respectively, 30 and 43%
yield, thus to the pyridine protected form of complex 3. The
1H NMR spectrum of complex 17 disclosed signals for the
with a slight excess of N-methylpyridine at dry-ice/acetone
temperature, a fast reaction leading to the pyridinium complex
1
salt 22 was observed. The H NMR spectrum of the new
complex is very close to that of complex 24, the intermediate
isolated by Casey26 upon reduction of 1 with KHB(OiPr)3,
followed by cation exchange: one observes indeed a signal for
pyridinium protons at δ 8.92, 7.90, and 7.66 ppm together with
a singlet for the proton of the carbene carbon at δ 6.01 ppm.
(28) Piers, E.; Soucy, M. Can. J. Chem. 1974, 52, 3563.
(29) Eisner, U.; Kuthan, J. Chem. ReV. 1972, 72, 1.
(30) Comins, D. L.; Abdullah, A. H. J. Org. Chem. 1982, 47, 4315.
(27) Cotton, F. A.; Darensburg, D. J.; Fang, A.; Kolthammer, B. W. S.;
Reed, D.; Thompson, J. L. Inorg. Chem. 1981, 20, 4090.

12050 J. Am. Chem. Soc., Vol. 118, No. 48, 1996
Rudler et al.
the benzylic proton at δ 5.06 ppm (vs δ 4.88 ppm for 24)
and signals at δ 3.09 and 3.43 ppm as two doublets of quar-
tets for the two diastereotopic protons of the ethoxy group. A
similar reaction was observed starting from complex 5a
which gave 23. Like 24, these N-methylpyridinium (R-
ethoxybenzyl or ethoxyalkyl)pentacarbonyl tungstates are slightly
air sensitive.
Reactivity of the Pyridinium Ylide Complexes. Displace-
ment of Pyridine by Triphenylphosphine. Exchange of pyri-
dine could be carried out quite easily: reaction of triphen-
ylphosphine with complex 17 led, after 15 min at room temp-
erature, to the known phosphorus ylide complex 4 in 70%
yield.13 The substitution of pyridine in 7a appeared to be more
Much better results were however observed in the case of
electron-rich olefins such as enol ethers: the reaction with these
substrates proved to be general and took place either at room
temperature or at reflux temperature of methylene chloride or
benzene. Thus, 2,3-dihydrofuran, the enol ethers of cyclopen-
tanone, norcamphor, and isopropenyl acetate reacted with
complex 17 at room temperature, leading to the isomeric
phenylcyclopropanes 28a-d in, respectively, 69, 79, 97, and
63% yield (see the Experimental Section).
Complex 7a reacted more sluggishly: transfer of the eth-
ylidene ligand occurred however again in the case of methyl-
2-heptene yet in low yield (observed by 1H NMR). In contrast,
enol ethers of norcamphor and acetophenone proved again to
be more reactive: they reacted in boiling benzene with complex
7a to give moderate yields of the corresponding methylcyclo-
propanes 28e,f (28 and 31% yield).
Reaction with Ethoxyacetylene. The nucleophilic alkyne
ethoxyacetylene, which is known to give, upon insertion into
complex 3, a new carbene complex 29,13 reacted in the same
way with complex 17 to give complex 29 yet in a very low 5%
yield. Again, 7a behaved differently: no complex arising from
the monoinsertion of the alkyne could be detected; instead, a
fast polymerization of ethoxyacetylene took place.
difficult since no reaction was observed after several hours at
room temperature. However, heating in refluxing methylene
chloride for 3 h led to complex 25 in 80% yield. The presence
of the phosphine on the carbene carbon was confirmed both by
the 1H NMR spectrum which showed a doublet of doublets for
the methyl group (3JHP ) 22.7 Hz, JHH ) 7 Hz) and a doublet
of quartets for the hydrogen on the carbene carbon (1JHP ) 14.4
Hz, JHH ) 7 Hz) and by the 13C NMR spectrum with a
characteristic signal for the ylide carbon at δ -12.21 ppm as a
doublet (JCP ) 15.2 Hz).
Reaction with Olefins: Intermolecular Cyclopropanation
Reactions. Since the pyridinium ylide complexes described
herein can be considered as the result of the interaction of
pyridine with W(0) and Cr(0) alkylidene complexes (Vide infra),
one might address the question of the reversibility of this
reaction. In such an event, a general access to alkylidene
complexes such as 3 transferable to olefins would be possible:
it has indeed been shown that simple olefins react with complex
3 at low temperature to give phenylcyclopropanes.13,16 How-
ever, at first glance, no transformation of complexes 7a and 17
was observed in solution by NMR spectroscopy. They appeared
to be quite stable although slow oxidation to the corresponding
aldehydes took place in the presence of oxygen.
In the hope that olefins might induce the elimination of
pyridine, they were reacted both at room temperature and in
refluxing dichloromethane or benzene with the ylide complexes.
No reaction was however observed with terminal olefins such
as 1-octene and complex 17 under these conditions. However,
in the case of the more reactive 2-methyl-1-heptene, the transfer
of the benzylidene group to the double bond took place in
refluxing methylene chloride and gave 26 as a mixture of two
isomers in 66% yield. In the same way, cyclopentene and
norbornene reacted with 17 to give the corresponding known31,32
phenylcyclopropanes 26a and 26b as mixtures of isomers in,
respectively, 55 and 27% yield (see the Experimental Section).
Olefins such as cyclopentadiene and pentamethylcyclopentadi-
ene, the reactivity of which has been found to be extremely
high toward complex 3 even at -20 °C,17 led, at room
temperature, to the same phenylcyclopropanes 27a,b in 30 and
40% yield.
Direct Intramolecular Cyclopropanation Reactions. In-
tramolecular cyclopropanation reactions promoted by carbene
complexes have found applications in the synthesis of natural
products or analogues.34,35 Although Fischer-type carbene
complexes of tungsten and chromium react only sluggishly with
olefins,36 alkene-carbene complexes of this type are known to
undergo easy intramolecular cyclopropanations provided that
the carbene carbon and the alkene are separated by three or
four methylene groups.35,37,38 The first successful reactions have
been observed in the case of complexes of the general structure
(34) Hoye, T. R.; Vyvyan, J. R. J. Org. Chem. 1995, 60, 4184.
(35) So¨derberg, B. J.; Hegedus, L. S. Organometallics 1990, 9, 3113.
(36) Do¨tz, K. H. Carbene Complexes in Organic Chemistry. In Transi-
tion Metal Carbene Complexes; Seyferth, D., Ed.; Verlag Chemie: Wein-
heim, 1983; pp 192-226.
(37) Casey, C. P.; Vollendorf, N. W.; Haller, K. J. J. Am. Chem. Soc.
1984, 106, 3754.
(38) Alvarez, C.; Rudler, H.; Daran, J. C.; Jeannin, Y. J. Chem. Soc.,
Chem. Commun. 1984, 574.
(31) Hesse, K.; Hurig, S.; Wenner, H. Liebigs Ann. Chem. 1982, 2079.
(32) Creary, X. J. Org. Chem. 1980, 45, 4653.
(33) Catellani, M.; Chiusoli, G. P. J. Organomet. Chem. 1982, 233, C-21.

Dihydropyridines in Organometallic Synthesis
J. Am. Chem. Soc., Vol. 118, No. 48, 1996 12051
30a (R ) R′ ) H), a result portending a similar behavior of
pyridinium ylide complexes derived from them. Since a
successful intramolecular reaction of complex 30a might lead
to bicyclo(3.1.0)hexane, a compound difficult to isolate from
the reaction medium due to its volatility, we choose to start
from the R-benzylated complex 30b.
31b as a 1:1 mixture of isomers, 30e, 30f, and 30g led to the
formation of almost exclusively a single isomer (95%). The
relative configurations of the substituents in these bicyclic
compounds could be established through careful analysis of the
1H NMR spectra along with NOE difference experiments, the
alkyl chain at C(2) being cis to the hydrogen atoms at the ring
junction.
Since a substituent in the R position with respect to the
carbene carbon seemed to destabilize the ylide complex (or to
hinder its formation), allowing thus a direct trapping of the
alkylidene complex by the intramolecularly located double bond,
the behavior of complex 34, containing in contrast to 30 a
saturated chain, was also examined. Confirmation of the
previous observation could be established: indeed, 34 reacted
with dihydropyridine to give instead of the ylide complex 35,
its decomposition product directly, the olefin 36 in 60% yield.
Surprisingly, when complex 30b was submitted to a slight
excess of dihydropyridine, a fast consumption of the starting
material was again observed. However, in contrast to the
previous cases, only trace amounts of the corresponding
pyridinium ylide complex could be detected by TLC or by
NMR. Moreover, when the reaction mixture was kept at room
temperature for a further few hours, organic compounds of low
polarity could be detected and isolated after workup and silica
gel chromatography. We were delighted to discover that indeed
a direct intramolecular cyclopropanation of the monosubstituted
double bond of complex 30b had taken place at room temper-
ature. All the spectroscopic data of the less polar compound
31b, obtained in 44% yield, and purified on silver nitrate
impregnated silica gel, were in agreement with such a bicyclic
structure. The 13C NMR spectrum confirmed the presence of
approximately a 1:1 mixture of isomers with 13 distinct signals
for the 14 expected aliphatic carbons of the two compounds,
whereas in the 1H NMR spectrum overlap of most of the signals
was observed, the signals for the hydrogens on the cyclopropane
giving rise to multiplets between δ 0.8 and -0.01 ppm. Two
side products were formed during this insertion reaction: the
diene 32b and the olefin 33b in, respectively, 18 and 4% yield.
Complexes 30c-g behaved similarly and led to the bicyclic
compounds 31c-g in, respectively, 40, 70, 40, and 35% yield.
However, subtle differences in the mode of formation of the
various organic products could be noted. Whereas complexes
30c and 30e-g behaved like 30b and gave directly, at room
temperature, the cyclopropanation products 31c,e-g, slightly
more vigorous conditions had to be applied to complex 30d
for its transformation into 31d: although the reduction reaction
took place as in the other examples, the presence of the
intermediate ylide complex for a long period of time was clearly
Thermolysis of Complex 14. Carbenes as well as alkylidene
complexes are known to insert into carbon-hydrogen bonds
especially when these are located R with respect to a
heteroatom.40-46 Complex 14 seemed to fulfill the structural
requirements for such an intramolecular cyclization reaction.
However, its thermolysis in boiling benzene did not lead to the
expected ether 37: a quantitative transformation into the alkene
38, the product of â-elimination, was instead observed.
Discussion
These experimental data bring to light two striking features.
The first one is the confirmation of the analogy which exists
between carbonyl compounds and alkoxycarbene complexes:
in both cases a smooth and clean reduction by the mild reducing
agents dihydropyridines takes place. The second one is the
possible application of the new reaction to the straightforward
synthesis of polycyclic systems.
Mechanism of the Formation of the Ylide Complexes. On
a formal point of view, these new pyridinium ylide complexes
can be considered as the result of a double stabilization of a
singlet carbene, by pyridine on the one hand and by a metal
pentacarbonyl on the other. Pyridine is indeed a typical trap
for singlet carbenes: the interaction of these species leads to
1
established by H NMR, with a characteristic signal for the
W-C-H proton at δ 4.65 ppm. After one night at room
temperature, the ylide complex was still detectable and the
reaction could only be driven to completion upon reflux of the
ethereal solution for an extra hour. The reaction products could
again be separated by silica gel chromatography. According
to the 1H and 13C NMR, the bicyclic compound 31d was
obtained as a single isomer in 70% yield. The shape and width
(septuplet, 21 Hz) of the signal due to the cyclopropane proton
at C(6) were in agreement with a trans geometry of the chain
and the five-membered ring.39 In contrast to 30b which gave
(40) Fischer, H.; Zeuner, S.; Schmid, J.; Hofmann, J. In AdVances in
Metal Carbene Chemistry; Schubert, U., Ed.; NATO ASI Series C;
Kluwer: Dordrecht, The Netherlands, 1989; Vol. 269, pp 185-188 and
references therein.
(41) Adams, J.; Spero, D. M. Tetrahedron 1991, 47, 1765.
(42) Doyle, M. P.; van Oeveren, A.; Westrum, L. J.; Protopopova, M.
N.; Clayton, T. W., Jr. J. Am. Chem. Soc. 1991, 113, 8982.
(43) Zhao, S. K.; Knors, C.; Helquist, P. J. Am. Chem. Soc. 1989, 111,
8527.
(44) Zhao, S. K.; Helquist, P. J. Org. Chem. 1990, 55, 5821.
(45) Zhao, S. K.; Mehta, G.; Helquist, P. Tetrahedron Lett. 1991, 32,
5753.
(39) Hoye, T. R.; Hanson, P. R.; Vyvyan, J. R. J. Org. Chem. 1994, 59,
4096.
(46) Wang, S. L. B.; Su, J.; Wulff, W. D.; Hoogsten, K. J. Am. Chem.
Soc. 1992, 114, 10665.

12052 J. Am. Chem. Soc., Vol. 118, No. 48, 1996
Rudler et al.
Scheme 4
interaction of 1,4-dihydropyridine was observed. Since the
reaction of dihydropyridine with 5a leaves this latter complex
unchanged, one can conclude that 8a is not formed from 5a
via a substitution reaction of pyridine by dihydropyridine. Such
substitution reactions can nevertheless occur: thus, in the case
of phosphines, displacement of pyridine takes place. These
reactions can be understood on the following grounds: the softer
phosphine displaces the harder pyridine from the soft carbene
carbon to give a complex in which the carbon-heteroatom bond
is stronger than in the starting complex. This assertion is
confirmed by the difference of reactivity with respect to
olefins: complex 17 reacts with cyclopentene at room temper-
ature to give the corresponding phenylcyclopropane whereas
no reaction is observed in the case of complex 4a even in
refluxing benzene. The chemical shift of the proton geminated
to the carbene carbon can be considered as a good criterion for
the assessment of the relative carbon-nitrogen bond strengths
in various complexes: the more this proton is deshielded, the
weaker the bond between the carbene carbon and the hetero-
atom. This appears clearly for the series of tungsten complexes
4b, 4a, 17 (2.71, 3.81, 6.03 ppm), 7a, and 25 (4.90, 2.47 ppm),
in which pyridine has been exchanged by phosphines, 7a and
8a (4.90, 3.80 ppm), where one finds successively pyridine and
the more basic dihydropyridine, and chromium complexes 21b,
19b, and 7b (4.23, 4.56, 4.60 ppm) in which a weak influence
of the methyl groups on pyridine can be detected.
Other pyridinium ylide complexes resulting from the interac-
tion of pyridine with stable alkylidene complexes have recently
been described and used as precursors for cyclopropanation
reactions: their mode of formation is however completely dif-
ferent.49 Moreover, to the best of our knowledge the stabiliza-
tion of dihydropyridine by formation of an ylide complex is
new, although it is known from organic chemistry that elec-
tron-withdrawing groups on nitrogen considerably stabilize
dihydropyridines. At this point it is interesting to notice that
since a carbon-nitrogen bond is formed upon interaction of
the alkylidene complex C with 1,2-dihydropyridine, dihydro-
pyridine reacts like an amine rather than an enamine: in this
latter case formation of a carbon-carbon bond would have been
expected. However, careful examination of the X-ray data
completely excluded such a possibility. Up to now, dihydro-
pyridines could be stabilized as tridentate ligands by coordina-
tion of the two double bonds and of nitrogen to Cr(CO)3 or
W(CO)3.50-53
organic pyridinium ylides detectable by UV/vis spectroscopy.47
Stabilization is due here to the interaction of the pyridine
nitrogen lone pair with the empty px orbital of the singlet
carbene. According to our observations, an important improve-
ment of the stability of this intermediate derives from the
interaction of the remaining occupied nonbonding σ-orbital of
the singlet carbene with an empty metal orbital of suitable
energy and symmetry, in the present instance, of W(CO)5 or
Cr(CO)5. The result of these interactions is a rehybridization
of the carbene carbon from sp2 to sp3, a feature which appears
in both crystal structures. A second way to describe these new
complexes, which is more related to their mode of formation
from alkoxycarbene complexes, is to consider them as the result
of the trapping reaction of an unstable electrophilic alkylidene
complex by pyridine. The role of dihydropyridine can thus be
considered as being triplicate (Scheme 4): (1) The starting
dihydropyridine transfers a hydride to the carbene complex with
formation of a pyridinium (R-alkoxyalkyl or aryl) tungsten or
chromium (pentacarbonyl) complex (A f B). This step is akin
to the reduction of a carbonyl group by dihydropyridine.48 (2)
The pyridinium activates the alkoxy group for its elimination,
by protonation. This gives the alkylidene complex and pyridine
(B f C). (3) The resulting pyridine reacts with the electrophilic
carbene carbon to lead to a stable pyridinium ylide complex
(C f D). Evidence for such a mechanism is provided by the
following observations: (1) The carbene complexes can also
be reduced by N-methyldihydropyridine. In that case, pyri-
dinium tungstates of type B are indeed formed and could be
characterized. (2) From the work of Casey and Fischer, it is
also known that such pyridinium tungstates readily eliminate
alcohol under acidic conditions to give, for R ) Ph, the
corresponding isolable alkylidene complex (1 f 3 vs B f
C).13,14 (3) Finally, since in the case of the alkylidene complex
3 the electrophilic nature of the carbene carbon is reflected by
its reaction with triphenylphosphine, the last step of the reaction,
the interaction of pyridine with the carbene carbon (Scheme 4,
C f D), is easily understood. Moreover, at this stage
competition between several nucleophiles of the reaction
medium (in the present instance pyridine and dihydropyridines)
can take place. One observes indeed the formation of two ylide
complexes, 7a and 8a, from complex 5a through the interaction
of the transient electrophilic alkylidene complex with, respec-
tively, pyridine and dihydropyridine. A plausible mechanism
for the formation of 8a is given in Scheme 4: interaction of
the alkylidene complex C with 1,2-dihydropyridine might lead
to the 1,2-dihydropyridinium ylide complex E, which upon a
(1,3) hydride shift would give the 2,5-dihydropyridinium
complex 8a. Surprisingly, no complex resulting from the
Reaction with Olefins. As far as the behavior of these
complexes with respect to various olefins is concerned, the
general lower reactivity of these ylide complexes as compared
for example with the reactivity of complex 3 implies that
displacement of pyridine prior to the reaction with the olefin
must probably take place. This could involve either an
associative or a dissociative mechanism, a fact which has yet
to be established by kinetic measurements. The high reactivity
of enol ethers can be considered as a good indication for a
substitution of pyridine by the substrate as the limiting step of
the reaction. This assumption is also confirmed by the easy
insertion of the nucleophilic alkyne ethoxyacetylene into
complex 17. The difference of reactivity between phenyl- and
alkyl-substituted pyridinium ylides already observed for tri-
(49) Djukic, J. P.; Young, Jr., V. G.; Woo, K. W. Organometallics 1994,
13, 3995.
(50) Ofele, K. Angew. Chem., Int. Ed. Engl. 1967, 6, 988.
(51) Kutney, J. P.; Bagder, R. A.; Cullen, W. R.; Greenhouse, R.; Noda,
M.; Ridaura-Sanz, V. E.; So, Y. H.; Zanarotti, A.; Worth, B. R. Can. J.
Chem. 1979, 57, 300.
(52) Denise, B.; Lafollee, S.; Parlier, A.; Rudler, H.; Vaissermann, J. J.
Organomet. Chem. 1995, 494, 43.
(53) Ragauskas, A. J.; Stothers, J. B. Can. J. Chem. 1985, 63, 2969.
(47) Modarelli, D. A.; Platz, M. S. J. Am. Chem. Soc. 1993, 115, 470
and references therein.
(48) Loewus, F. A.; Westheimer, F. H.; Vennesland, B. J. Am. Chem.
Soc. 1953, 75, 5018.

Dihydropyridines in Organometallic Synthesis
J. Am. Chem. Soc., Vol. 118, No. 48, 1996 12053
Table 5. Crystallographic Data for Complexes 7a and 8a
phenylphosphine is corroborated by their behavior toward
olefins: satisfactory results could be obtained in the case of
activated double bonds, the main reaction being otherwise the
thermal â-elimination. The greatest achievements stem however
from the direct intramolecular cyclopropanation reactions
observed in the case of alkene-carbene complexes, although
no attempts have been made, up to now, to optimize the reaction
conditions. Several aspects of the cyclization reactions deserve
a comment. First, complete retention of the stereochemistry
of the alkene precursor is observed in the case of complex 30d
since 31d was isolated as a single isomer.54 This result is
reminiscent of the reaction of complex 3 with (E)- and (Z)-
olefins during which conservation of the stereochemistry was
observed.16 Second, complexes 30b and 30c gave rise to a 1:1
mixture of isomers. This means that a facial selectivity exists:
if the transient carbene complex bearing in the R position the
pro-R group gives a 80% addition to the re face of the double
bond, then the carbene complex bearing the pro-S group leads
to a 20% addition to this same face. Third, in the case of
complexes 30e-g, and in contrast to the previous cases, high
diastereoselectivity is observed in spite of the presence of an R
substituent. The exact reasons for this behavior are not clear
for the moment.
C12H11O5NW
433.07
11.050(5)
15.215(6)
9.299(3)
90
113.88(3)
90
1430
C12H9O5NW
431.0
10.847(4)
15.138(5)
9.308(6)
90.
113.64(5)
90.
1400
Fw
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
4
4
crystal system
space group
linear absorption
coefficient µ (cm-1
monoclinic
P21/a
82.7
monoclinic
P21/a
84.4
)
density F (g‚cm-3
diffractometer
radiation
)
2.01
2.04
Philips PW1100
Mo KR (λ )
0.710 69 Å)
ω/2θ
1.20 + 0.345 tan θ
2-25
room temperature
Philips PW1100
Mo KR (λ )
0.710 69 Å)
ω/2θ
1.20 + 0.345 tan θ
2-25
room temperature
scan type
scan range (deg)
θ limits (deg)
temperature of
measurement
octants collected
h, -13, 12; k, 0, 18; h, -12, 11; k, 0, 18;
l, 0, 11 l, 0, 10
2797 2687
2518 2416
no. of data collected
no. of unique data
collected
Conclusion
no. of unique data used 1386 (Fo2 > 3σ(F02)) 1451 (Fo2 > 3σ(Fo ))
2
Most of our efforts have been focused on the one hand on
the generalization of the preparation and structure determination
of these new ylide complexes and on the other hand on their
thermolysis in the presence of olefins. Whereas in the case of
alkenes tethered to carbene complexes the results were beyond
our expectations, alkyl-substituted pyridinium ylides are still
reluctant to release intermolecularly in a useful way their carbene
moiety. It is however clear that these reactions might be induced
otherwise, for instance by chemical or electrochemical oxidation
or reduction, or by photochemistry which should also weaken
the carbon-nitrogen bond and thus improve the reactivity. Work
is in progress toward these goals and also to extend the
intramolecular reactions first to 1,6-alkene-carbene complexes,
which should lead to bicyclo(4.1.0)heptane systems common
in natural products, and to alkyne-containing alkene-carbene
complexes.
for refinement
R(int)
0.069
0.061
0.0477
0.0499 (w ) 1.0)
R ) ∑||Fo| - |Fc||/∑|Fo| 0.0440
Rw ) [∑w(|Fo| -
0.0470 (w ) 1.0)
2
|Fc|)2/∑wFo ]1/2
absorption correction
DIFABS (min 0.78, DIFABS (min 0.65,
max 1.43)
max 1.29)
extinction parameter
no
no
(×10-6
)
goodness of fit s
1.02
173
-0.75
0.97
1.31
172
-1.53
0.86
no. of variables
∆F(min) (e‚Å-3
∆F(max) (e‚Å-3
)
)
X-ray Structure Determinations. Data were collected on an Enraf-
Nonius CADA diffractometer. Accurate cell dimensions and orientation
matrices were obtained by least-squares refinements of 25 accurately
centered reflections. No significant variations were observed in the
intensities of two checked reflections during data collections. Complete
crystallographic data and collection parameters are listed in Table 5.
The data were collected for Lorentz and polarization effects. Computa-
tions were performed by using the PC version of CRYSTALS.62
Scattering factors and corrections for anomalous absorption were taken
from ref 63. The structures were solved by using standard Patterson-
Fourier techniques and refined by full-matrix least squares with
anisotropic thermal parameters for all non-hydrogen atoms. Hydrogen
atoms were introduced in calculated positions in the last refinement,
and only an overall isotropic thermal parameter was refined.
Experimental Section
General Methods. 1H and 13C NMR spectra were recorded on
Bruker AC 200, ARX 400, and AM 500 spectrometers. IR spectra
were recorded on a Perkin-Elmer 1420 spectrophotometer. Mass
spectra were recorded on a ZAB HSQ (Fisons) instrument. Column
chromatography was performed with Merck silica gel (70-230 mesh)
using various ratios of ethyl acetate/light petroleum ether or dichlo-
romethane/light petroleum ether as eluent. For the separation of the
olefins, silica gel was impregnated with silver nitrate (5% by weight)
and reactivated by heating under vacuum. All reagents were obtained
from commercial suppliers and used as received. Reactions were
performed under an argon atmosphere in carefully dried glassware.
Benzene, tetrahydrofuran (THF), and diethyl ether were distilled from
sodium/benzophenone ketyl under a nitrogen atmosphere. Dichlo-
romethane (CH2Cl2) was distilled from phosphorus pentoxide under a
nitrogen atmosphere. Carbene complexes 1, 5a, 5b, 9, and 15 (R′ )
R′ ) H)55-60 and the various dihydropyridines24,29,30 were prepared
according to published methods.
General Procedure for the Preparation of the Pyridinium Ylide
Complexes: Reaction of (CO)5WdC(CH3)OEt (5a) with 1,4-Dihy-
dropyridine. Freshly prepared 1,4-dihydropyridine (obtained from
N-carbomethoxydihydropyridine (6 mmol) and methyllithium according
to the literature24) in diethyl ether (80 mL) was added at room
(58) Darensbourg, M. Y.; Darensbourg, D. J. Inorg. Chem. 1970, 9, 32.
(59) Alvarez, C.; Pacreau, A.; Parlier, A.; Rudler, H.; Daran, J. C.
Organometallics 1987, 6, 1057-1064.
(60) Alvarez, C.; Parlier, A.; Rudler, H.; Daran, J. C.; Jeannin, Y. J.
Chem. Soc., Chem. Commun. 1984, 576.
(61) Strohmeier, W.; Gerlach, K. Z. Naturforsch. 1961, 15b, 413 and
621.
(54) Note added in proof: the reaction of the Z isomer 30d′ led also to
a single isomer, confirming the high stereoselectivity of the cyclopropanation
reaction (see the Experimental Section).
(55) Fischer, E. O.; Maasbo¨l, A. Angew. Chem., Int. Ed. Engl. 1964, 3,
580.
(56) Aumann, R.; Fischer, E. O. Angew. Chem., Int. Ed. Engl. 1967, 6,
878.
(62) Watkins, D. J.; Carruthers, J. R.; Bettridge, P. W. Crystals User
Guide; Chemical Crystallography Laboratory, University of Oxford: Oxford,
U.K., 1988.
(63) Cromer, D. T. International Tables for X-ray Crystallography;
Kynoch Press: Birmingham, U.K., 1974; Vol. IV.
(57) Fischer, E. O.; Maasbo¨l, A. J. Organomet. Chem. 1968, 12, 15.

12054 J. Am. Chem. Soc., Vol. 118, No. 48, 1996
Rudler et al.
temperature to the carbene complex 5a (2.0 g, 3 mmol) in diethyl ether
(20 mL). The solution turned rapidly from orange to red. Evaporation
of the solvent gave a residue which was rapidly chromatographed on
silica gel. Elution with dichloromethane/petroleum ether (20/80) gave
(CO)5W(pyridine) (6a) (0.15 g, 7.5%).61 Elution with dichloromethane/
petroleum ether (60/40) gave (CO)5W--(CHCH3)(pyridine)+ (7a) (0.86
g, 66%). Spectral data for 6a: yellow crystals, from methylene
dichloride/hexane, mp 114 °C; 1H NMR (CDCl3) δ 8.83 (dd, 2H, J )
5 and 1.4 Hz), 7.79 (tt, 1H, J ) 7.7 and 1.4 Hz), 7.28 (m, 2H); 13C
NMR (CDCl3) δ 202.35 (CO), 199.47 (CO), 155.99, 137.39, 125.63;
IR (CHCl3) 2060, 1970, 1930 cm-1. Anal. Calcd for C10H5NO5W:
C, 29.79; H, 1.24; N, 3.47. Found: C, 29.70; H, 1.28; N, 3.59. Spectral
data for 7a: orange crystals, from dichloromethane/hexane, mp 127
and W(CO)6 as a yellow oil in 52% yield: 1H NMR (CDCl3) δ 7.31-
7.23 (m, 3H), 6.93-6.85 (m, 2H), 4.87 (q, 2H, OCH2), 3.94 (t, 2H,
PhOCH2), 3.27 (t, 2H, WdCCH2), 1.76 (m, 4H), 1.60 (t, 3H, CH2-
CH3); 13C NMR (CDCl3) δ 333.46 (WdC), 203.28 (CO), 197.40 (CO),
158.99 (OsC), 129.51, 120.76, 120.54, 114.57, 80.83 (OCH2), 76.47
(OCH2), 67.35, 64.75, 28.60, 23.14; HRMS calcd (obsd) for C18H18O7W+
530.0562 (530.0556).
Reaction of 1,2- and 1,4-Dihydropyridines with Complex 9:
Formation of (CO)5W--C(H)((CH2)2Ph)(C5H5N)+ (10). This com-
plex was obtained as above in 47% yield as an orange solid: mp 113
1
°C; H NMR (CDCl3) δ 8.47 (d, 2H), 7.83 (t, 1H), 7.57 (t, 2H), 7.19
(m, 5H), 4.67 (dd, 1H, J ) 9.5 and 5.6 Hz, W-C-H), 2.99-2.74 (m,
2H), 2.71-2.49 (m, 2H); 13C NMR (CDCl3) δ 204.35 (CO), 201.78
(CO), 140.86, 139.98, 136.83, 128.51, 128.26, 128.74, 126.04 (Ar, Py),
63.50 (W-C), 45.34, 35.98. Anal. Calcd for C19H15NO5W: C, 43.76;
H, 2.88; N, 2.68. Found: C, 43.78; H, 3.02; N, 2.52.
Reaction of 1,2- and 1,4-Dihydropyridines with Complex 15:
Formation of the Pyridinium Ylide Complex (CO)5W--C(H)((CH2)8-
CHdCH2)(C5H5N)+ (16). This complex was obtained as above in
42% yield as orange crystals: mp 50 °C; 1H NMR (CDCl3) δ 8.51 (d,
2H), 7.83 (t, 1H), 7.58 (t, 2H), 5.80 (m, 1H, CHdC), 4.92 (m, 2H,
CdCH2), 4.66 (dd, 1H, J ) 10 and 5.5 Hz, WsCsH), 2.42 (m, 2H),
2.02 (m, 2H), 1.23 (m, 12 H); 13C NMR (CDCl3) δ 204.67 (CO), 202.08
(CO), 140.04, 139.26, 138.53, 136.67, 126.84, 114.22 (CdC, Py), 64.51
(WsCsH), 44.17, 33.84, 29.60, 29.53, 29.48, 29.35, 29.11 (CH2). Anal.
Calcd for C21H25NO5W: C, 45.42; H, 4.51; N, 2.52. Found: C, 45.42;
H, 4.56; N, 2.49.
Reaction of 1,2- and 1,4-Dihydropyridines with Complex 11:
Formation of (CO)5W--C(H)((CH2)3Ph)(C5H5N)+ (12). 12 was
obtained from complex 11 (6.6 g, 0.13 mmol) as above: yellow solid
(2.01 g, 28.5%), mp 128 °C; 1H NMR (CDCl3) δ 8.39 (d, 2H), 7.79 (t,
1H), 7.50 (t, 2H), 4.65 (dd, 1H, J ) 5.6 and 10.2 Hz, W-C-H), 2.70-
2.52 (m, 4H), 1.60-1.48 (m, 2H); 13C NMR (CDCl3) δ 204.44 (CO),
201.96 (CO), 142.14, 139.67, 136.52, 128.45, 126.78, 125.97 (Ar, Py),
64.16 (W-C-H), 43.60, 35.45, 31.45 (3CH2). Anal. Calcd for
C20H17NO5W: C, 44.87; H, 3.18; N, 2.62. Found: C, 44.98; H, 3.23;
N, 2.55.
Reaction of 1,2- and 1,4-Dihydropyridines with Complex 13:
Formation of the Pyridinium Ylide Complex (CO)5W--C(H)((CH2)4-
OPh)(C5H5N)+ (14). This complex was obtained as above, in 50%
yield as an orange solid: mp 69 °C; 1H NMR (CDCl3) δ 8.50 (d, 2H),
7.82 (t, 1H), 7.56 (t, 2H), 7.24 (m, 3H), 6.95-6.79 (m, 2H), 4.68 (1H,
dd, J ) 5.4 and 10 Hz), 3.93 (t, 2H, OCH2), 2.69 (m, 1H, W-C-CH),
2.52 (m, 1H, W-C-CH), 1.29 (m, 2H), 1.39 (m, 2H); 13C NMR
(CDCl3) δ 204.5 (CO), 201.97 (CO), 158.9, 139.98, 136.69, 129.55,
126.65, 120.71, 114.45 (Ar, Py), 67.39, 64.20, 43.69, 28.64, 26.15.
Anal. Calcd for C21H19NO6W: C, 44.61; H, 3.36; N, 2.48. Found:
C, 44.77; H, 3.46; N, 2.35.
1
°C; H NMR (CDCl3) δ 8.55 (d, 2H, J ) 6 Hz), 7.82 (t, 1H, J ) 7.5
Hz), 7.59 (t, 2H, J ) 6.7 Hz), 4.90 (q, 1H, J ) 7 Hz, CHMe), 2.35 (d,
3H, J ) 7 Hz, CHMe); 13C NMR (CDCl3) δ 204.51 (CO), 201.93 (CO),
139.22, 136.17, 126.61, 57.16 (CHMe), 30.72 (Me). Anal. Calcd for
C12H9NO5W: C, 33.42; H, 2.08; N, 3.25. Found: C, 33.49; H, 2.17;
N, 3.35.
Reaction of (CO)5WdC(CH3)OEt (5a) with a Mixture of 1,2-
and 1,4-Dihydropyridines: Formation of (CO)5W--C(H)(CH3)-
(N+C5H7) (8a). Under the same conditions as above, besides complexes
6a and 7a, pure fractions of complex 8a could be eluted with methylene
chloride/petroleum ether (20/80) and isolated in 17% yield. Spectral
data for yellow crystals, mp 100 °C, from methanol/dichloromethane;
1H NMR (CD2Cl2) δ 7.81 (br s, 1H, C(12)), 5.90 (m, 2H, C(9,10)-H),
4.95-4.79 (dt, 1H, J ) 20 and 7 Hz, C(8)-H), 4.25-4.12 (dt, 1H, J )
20 and 7 Hz, C(8)-H), 4.19 (br q, 1H, CHMe), 3.20 (m, 2H, C(11)-
H2), 2.11 (d, 3H, J ) 8 Hz, CHMe). Anal. Calcd for C12H11NO5W:
C, 33.26; H, 2.54; N, 3.23. Found: C, 32.23; H, 2.17; N, 3.19.
Reaction of (CO)5CrdC(CH3)OEt (5b) with 1,2-Dihydropyridine:
Formation of the Pyridinium Ylide Complex (CO)5Cr--C(H)-
(CH3)(C5H5N)+ (7b). Under the same conditions as above, complex
5b gave a mixture of complexes 6b (8%) and 7b (20%). Spectral data
1
for 6b: yellow solid, mp 95 °C; H NMR (CDCl3) δ 8.57 (dd, 2H, J
) 6.5 and 1.6 Hz), 7.42 (tt, 1H, J ) 7.6 and 1.5 Hz), 7.25 (m, 2H);
13C NMR (CDCl3) δ 220.72 (CO), 214.32 (CO), 155.34, 137.17, 124.88.
Anal. Calcd for C10H5NO5Cr: C, 44.28; H, 1.84; N, 5.16. Found: C,
44.09; H, 1.95; N, 5.10. Spectral data for 7b: orange solid, mp 112
°C, 1H NMR (CDCl3) δ 8.42 (d, 2H, J ) 5.6 Hz), 7.75 (t, 1H, J ) 4.5
Hz), 7.6 (t, 2H, J ) 6 Hz), 4.6 (q, 1H, J ) 7 Hz, CHMe), 2.10 (d, 3H,
J ) 7 Hz, Me); 13C NMR (CDCl3) δ 224.87 (CO), 220.06 (CO), 138.92,
135.77, 126.57, 63.83 (CHMe), 28.70 (Me). Anal. Calcd for C12H9-
NO5Cr: C, 48.10; H, 3.01; N, 4.68. Found: C, 47.84; H, 3.10; N,
4.62.
Reaction of (CO)5WdC(Ph)OEt (1a) with 1,2-Dihydropyridine:
Formation of the Pyridinium Ylide Complex (CO)5W--C(H)(Ph)-
(C5H5N)+ (17). Under the same conditions as above, complex 1 gave
a mixture of 6a (31%) and 17 (43%). Spectral data for 17: orange
solid, mp 105 °C; 1H NMR (CDCl3) δ 8.92 (d, 2H, J ) 5.6 Hz), 7.90
(t, 1H, J ) 7.7 Hz), 7.66 (t, 2H, J ) 7 Hz), 7.31 (m, 4H), 7.15 (m,
1H), 6.03 (t, 1H, J ) 3.4 Hz); 13C NMR (CDCl3) δ 203.93 (CO), 201.56
(CO), 148.68, 141.92, 138.43, 128.7, 127.61, 126.70, 125.75, 70.82
(CHPh). Anal. Calcd for C17H11NO5W: C, 41.38; H, 2.23; N, 2.84.
Found: C, 41.27; H, 2.34; N, 2.71.
(1-Ethoxy-4-phenylbutylidene)pentacarbonyltungsten(0) (11). To
a suspension of W(CO)6 (10.55 g, 3 × 10-2 mol) in diethyl ether was
added a solution of (3-phenylpropyl)lithium obtained from 3-phenyl-
propyl iodide (7.35 g, 3 × 10-2 mol) in diethyl ether (130 mL) and
pentane (200 mL) and tBuLi (38 mL, 1.6 M in pentane, 6 × 10-2 mol).
After 3 h at room temperature, the solvents were evaporated under
vacuum. Water (180 mL) was added to the residue, followed by
petroleum ether (80 mL) and triethyloxonium fluoroborate (6.3 g).
Workup as usual gave complex 11 (12.71 g, 85%) as a yellow oil: 1H
NMR (CDCl) δ 7.35-7.16 (m, 5H, Ar), 4.88 (q, 2H, OCH2), 2.64 (m,
2H, CH2Ph), 1.82 (m, 2H, -CH2-), 1.60 (t, 3H, CH3); 13C NMR
(CDCl3) δ 333.43 (WdC), 203.35 (CO), 197.37 (CO), 141.48, 128.52,
128.46, 126.17 (Ar), 80.75 (OCH), 64.69 (dCCH), 35.42 (C-Ph), 28.15
(-CH2-), 14.60 (CH2CH3); HRMS calcd (obsd) for C17H16O6W+
500.0456 (500.0457).
Reaction of 4-Methyldihydropyridine with Complex 5b: Forma-
tion of the Pyridinium Ylide Complex (CO)5Cr--C(H)(CH3)-
(C6H8N)+ (19b). A solution of 4-methyldihydropyridine obtained from
N-carbomethoxy-4-methyldihydropyridine (2.3 g, 15 mmol) and MeLi
(28 mL, 45 mmol) was added to complex 5b (4 g, 15 mmol) at room
temperature. Workup as above followed by silica gel chromatography
first gave complex 18b (0.37 g, 9%) and then complex 19b (1.2 g,
25%). Spectral data for 18b: yellow solid, mp 97 °C; 1
H NMR (CDCl3)
δ 8.45 (d, 2H, J ) 5 Hz), 7.08 (d, 2H, J ) 6 Hz), 2.41 (s, 3H); 13C
NMR (CDCl
3) δ 220.78 (CO), 214.47 (CO), 154.79, 149.21, 125.84,
20.83. Anal. Calcd for C11H11NO5Cr: C, 46.31; H, 2.46; N, 4.91.
Found: C, 46.27; H, 2.53; N, 4.96. Spectral data for 19b: orange
crystals, mp 63 °C; 1
H NMR (CDCl) δ 8.36 (d, 2H, J ) 5.7 Hz), 7.41
(d, 2H, J ) 5.4 Hz), 4.56 (q, 1H, J ) 7 Hz, W-C-H), 2.53 (s, 3H,
Me), 2.11 (d, 3H, J ) 7 Hz, CHMe); 13C NMR (CDCl3) δ 224.86
(CO), 220.36 (CO), 148.92, 138.42, 127.64, 62.9 (CHMe), 28.90 (Me),
21.18 (CHMe). Anal. Calcd for C
13H11NO5Cr: C, 49.84; H, 3.51; N,
4.47. Found: C, 49.98; H, 3.50; N, 4.57.
Reaction of 4-Methyl-1,4-dihydropyridine with Complex 5a:
Formation of the Pyridinium Ylide Complex (CO)5W--C(H)(CH3)-
(C6H6N)+ (19a). This complex was obtained as above upon silica gel
chromatography which gave first complex 18a in 12% yield and then
complex 19a in 23% yield. Spectral data for complex 18a: yellow
crystals, mp 118 °C; 1H NMR (CDCl3) δ 8.66 (dd, 2H, J ) 5.2 and 1
(1-Ethoxy-5-phenoxypentylidene)pentacarbonyltungsten(0) (13).
This complex was obtained as above from the corresponding iodide

Dihydropyridines in Organometallic Synthesis
J. Am. Chem. Soc., Vol. 118, No. 48, 1996 12055
Hz), 7.07 (d, 2H, J ) 6 Hz), 2.39 (s, 3H, Me); 13C NMR (CDCl3) δ
202.73 (CO), 199.22 5CO), 155.77, 149.93, 128.82, 21.39. Anal. Calcd
for C11H7NO5W: C, 31.65; H, 1.68; N, 3.35. Found: C, 31.81; H,
1.62; N, 3.40. Spectral data for complex 19a: orange solid, mp 75
°C; 1H NMR (CDCl3) δ 8.36 (d, 2H, J ) 6.7 Hz), 7.39 (d, 2H, J ) 6.4
Hz), 4.80 (q, 1H, J ) 7 Hz, CHMe), 2.46 (s, 3H, Me), 2.31 (d, 3H, J
) 7 Hz, CHMe); 13C NMR (CDCl3) δ 204.69 (CO), 202.10 (CO),
149.42, 138.81, 127.25, 55.99 (CHMe), 30.99 (Me), 21.27 (CHMe).
Anal. Calcd for C13H11NO5W: C, 35.05; H, 2.47; N, 3.14. Found:
C, 35.04; H, 2.47; N, 3.21.
δ 39.14 (JWP ) 81.8 Hz). Anal. Calcd for C25H19WO5P: C, 48.87;
H, 3.09. Found: C, 48.96; H, 3.21.
1-Phenyl-2-methyl-2-pentylcyclopropane (26) was obtained upon
refluxing complex 17 (0.1 g, 0.2 mmol) and 2-methyl-1-heptene (0.15
mL, 5 equiv) in methylene chloride (10 mL) for 10 h. Evaporation of
the solvent followed by silica gel chromatography gave with petroleum
ether as the eluent compound 26 (0.027 g, 66%, 60/40 mixture of two
isomers) as an oil: 1H NMR (CDCl3) δ 7.14-7.05 (m, 10H, Ar), 1.78
(m, 2H, CHPh), 1.38-1.18 (m, 10H), 1.10 (s, 3H, CH3), 1.08-1.03
(m, 4H), 0.84-0.73 (m, 4H), 0.67 (s, 11H, 3CH3, 2CH); 13C NMR
(CDCl3) δ 140.35, 140.17, 129.03, 128.95, 127.92, 127.83, 125.49 (Ar),
41.50 (CH2), 33.68 (CH2), 32.25 (CH2), 32.10 (CH2), 30.31 and 29.83
(Cph), 26.80 and 26.31 (CH2), 24.74 (CH3), 23.37 and 23.15 (Cq), 22.88
and 22.64 (CH2), 17.94 and 17.76 (CH2 cyclopropane), 17.64 (CH3),
Reaction of 2-Methyl-1,2-dihydropyridine with Complex 5b:
Formation of the Pyridinium Ylide Complex (CO)5Cr--C(H)-
(CH3)(C6H6N)+ (21b). A solution of 2-methyl-1,2-dihydropyri-
dine obtained from N-carbomethoxy-1,2-dihydropyridine (2.3 g, 15
mmol) and MeLi (28 mL, 45 mmol) was added to a solution of com-
plex 5b (4 g, 15 mmol) at room temperature. After workup and
silica gel chromatography as above, complex 20b (0.19 g, 4%)
and then complex 21b (0.36 g, 8%) were isolated. Spectral data for
complex 20b: yellow crystals, mp 99 °C; 1H NMR (CDCl3) δ 8.40 (d,
2H, J ) 6 Hz), 7.04 (d, 2H, J ) 6 Hz), 2.35 (s, 3H, CH3); 13C NMR
(CDCl3) δ 221.57 (CO), 214.8 (CO), 154.79, 149.57, 126.17, 126.0,
21.15 (Me). Anal. Calcd for C11H7NO5Cr: C, 46.31; H, 2.46; N, 4.91.
Found: C, 46.18; H, 2.42; N, 4.85. Spectral data for complex 21b:
+
14.24 (CH3), 14.09 (CH3); HRMS calcd (obsd) for C15H22 202.1721
(202.1722).
exo- and endo-6-phenylbicyclo(3.1.0)hexane (26a) were obtained
from complex 17 (0.38 g, 0.77 mmol) and cyclopentene (10 mL) at
the reflux temperature of the olefin for 12 h. Workup as above gave
a 3/1 mixture of the endo and exo isomers of 26a (0.60 g, 55%), the
physical properties of which were in agreement with those of the
literature.13
exo-3-Phenyltricyclo(3.2.1.02,4)octane (26b) was obtained as above
from complex 17 (0.20 g, 0.4 mmol) and norbornene (0.10 g, 0.5 mmol)
at the reflux temperature of CH2Cl2 as an oil (0.02 g, 27%, mixture of
two isomers), the physical properties of which were in agreement with
those of the literature.32
2-Phenylbicyclo(3.1.0)hex-4-ene (27a) was obtained from complex
17 (0.25 g, 0.5 mmol) and cyclopentadiene (2 mL, 3 mmol) in CH2Cl2
at room temperature for 1 h. Evaporation of the solvent followed by
silica gel chromatography gave 27a as an oil (0.025 g, 30%, one
isomer). The spectroscopic data of this product were in all respect
identical with those of the known endo isomer.22
1
orange crystals, mp 93 °C; H NMR (CDCl3) δ 8.58 (d, 1H, J ) 6
Hz), 7.57 (m, 2H), 7.41 (d, 1H, J ) 6 Hz), 4.25 (q, 1H, J ) 6.8 Hz,
Cr-C-H), 2.08 (d, 3H, J ) 6.8 Hz, CHCH3); 13C NMR (CDCl3) δ
225.25 (CO), 220.18 (CO), 148.68, 139.31, 135.03, 128.5, 127.43,
124.76, 55.66 (CHMe), 30.08 (CMe), 21.23 (CHMe). Anal. Calcd
for C13H11NO5Cr: C, 49.84; H, 3.51; N, 4.47. Found: C, 49.81; H,
3.56; N, 4.42.
Reaction of N-Methyl-1,4-dihydropyridine with Complex 1:
Formation of (CO)5W--C(Ph)(OEt)HCH3N+(C5H5N) (22). A solu-
tion of N-methyl-1,4-dihydropyridine (0.085 g) in diethyl ether (20 mL)
was added to a solution of complex 1 (1 g, 2.5 mmol) in dichlo-
romethane (10 mL) at -78 °C. The solution turned instantly to dark
red. After warming to 0 °C, the solvent was evaporated under vacuum
to give an oil which was washed with ice-cold hexane: 1H NMR
(CDCl3) δ 9.11 (d, 2H, J ) 6 Hz, NHC), 8.71 (t, 1H, J ) 7 Hz, dCH),
8.30 (m, 2H, CHd), 4.64 (s, 3H, NCH3), 3.64 (dq, 1H, OCHH), 3.23
(dq, 1H, OCHH), 3.14 (q, 1H, CHCH3), 1.15 (t, 3H, CH3CH2), 0.90
(d, 3H, J ) 6.6 Hz, CHCH3); 13C NMR (CDCl3) δ 205.10 (CO), 192.37
(CO), 146.52 (NCH), 129.50, 128.04, 126.83, 122.43, 120.31 (Ar,
PyMe), 79.83 (CH), 67.22 (OCH2), 49.69 (NCH3), 16.64 (CH3).
Reaction of N-Methyl-1,4-dihydropyridine with Complex 5a:
Formation of (CO)5W--C(CH3)(OEt)HCH3N+(C5H5N) (23). Under
the same conditions as above, complex 23 was isolated as a dark red
oil which was not further purified. Spectral data: 1H NMR (CDCl3)
δ 9.12 (d, 2H, J ) 6 Hz), 8.72 (t, 1H, J ) 7 Hz), 8.27 (m, 2H), 8.00-
7.01 (m, 5H), 5.05 (s, 1H, CHPh), 4.65 (s, 3H, NsCH3), 3.42 (m, 1H,
OCHH), 3.06 (m, 1H, OCHH), 1.09 (t, 3H, CH3CH2O); 13C NMR (CD3-
COCD3) δ 205.1, 192.37 (CO), 146.52 (NCHd), 129.17 (dCH), 97.43
(CHCH3), 64.60 (OCH2), 54.97 (NCH3), 16.35 (CHCH3), 16.0
(OCH2CH3).
1,2,3,4,5-Pentamethyl-endo-6-phenylbicyclo(3.1.0)hex-2-ene (27b)
was obtained as above from complex 17 (0.30 g, 0.6 mmol) and
pentamethylcyclopentadiene (0.27 g, 2 mmol), in benzene at room
temperature for 2 h. Workup as usual gave 27b as an oil (0.054 g,
40%): 1H NMR (CDCl3) δ 7.25-6.96 (m, 5H, Ar), 1.97 (q, J ) 7 Hz,
CHCH3), 1.70 (s, 1H, CHPh), 1.65 (s, 3H, dCCH3), 1.30 (s, 3H,
dCCH3), 1.10 (s, 3H, CH3), 0.98 (d, J ) 7 Hz, CHCH3); HRMS calcd
+
(obsd) for C17H25 226.1721 (226.1721).
2-Oxa-6-phenylbicyclo(3.1.0)hexane (28a) was obtained from
complex 17 (0.30 g, 0.6 mmol) and dihydrofuran (0.15 mL, 2 mmol),
in benzene (8 mL) at room temperature. Workup as usual gave 28a
as an oil (0.66 g, 69%): 1H NMR (CDCl3) δ 7.27-7.14 (m, 5H, Ar),
4.16 (dd, J ) 5 Hz, CHO), 3.71-2.46 (m, 2H, OCH2), 2.04-1.71 (m,
2H, CH2), 1.86 (m, 1H, CHPh), 1.83 (m, 1H, CH); 13C NMR (CDCl3)
δ 135.0, 129.6, 127.7, 125.7 (Ar), 69.4 (CH2), 61.6 (OCH), 26.0
(CHPh), 25.3 (CH2), 20.7 (CH); HRMS calcd (obsd) for C11H12O+
160.0888 (160.0888).
1-Ethoxy-6-phenylbicyclo(3.1.0)hexane (28b) was obtained from
complex 17 (0.54 g, 1.09 mmol) and the ethoxy enol ether of
cyclopentanone (0.26 g, 2.1 equiv) in dichloromethane at room
temperature for 24 h. Workup as above gave compound 28b (0.175
g, 79%) as a 2/1 mixture of the endo/exo isomers. Spectral data for
the exo isomer (minor): 1H NMR (CDCl3) δ 7.33-7.09 (m, 5H, Ar),
3.76-3.69 (m, 1H, OCH), 2.43 (d, 1H, CHPh), 2.07-1.98 (m, 3H,
C(2)-H2 and C(4)-H), 1.86-1.83 (m, 1H, C(5)-H), 1.60-1.55 (m, 1H,
C(4)-H), 1.38-1.27 (m, 1H, C(3)-H), 1.26 (t, 3H, CH3), 0.08-0.03
(m, 1H, C(3)-H); 13C NMR (CDCl3) δ 137.1, 129.0, 128.4, 125.0 (Ar),
74.5 (C(1)), 64.3 (C(7)), 29.9 (C(6)), 24.9 (C(4)), 22.3 (C(3)), 15.8
(C(8)). Spectral data for the major endo isomer: 1H NMR (CDCl3) δ
7.33-7.09 (m, 5H, Ar), 3.49-3.46 (m, 1H, C(7)-H), 3.03-3.00 (m,
1H, C(7)-H), 2.07-1.68 (m, 3H, C(2)-H2, C(3)-H2, C(4)-H2, C(5)-H),
0.93 (t, 3H, CH3); 13C NMR (CDCl3) δ 139.1, 128.9, 128.2, 127.7 (Ar),
75.3 (C(1)), 64.1 (C(7)), 31.6 (C(6)), 29.9 (C(5)), 28.7 (C(2)), 24.9
(C(4)), 22.3 (C(3)), 15.8 (C(8)); HRMS calcd (obsd) for C14H18O+
202.1357 (202.1357).
Phosphorus ylide (CO)5W--C(Ph)(H)P+Ph3 (4a) was obtained
from complex 17 (0.2 g, 0.4 mmol) and PPh3 (0.127 g, 1.2 equiv), in
methylene chloride (10 mL) at room temperature for 15 min. Evapora-
tion of the solvent followed by silica gel chromatography gave with
petroleum ether/dichloromethane as eluent complex 4a as a yellow solid
(0.24 g, 90%). Its spectral data were in all respect identical to those
of the literature: 31P NMR (CDCl3) δ 30.99 (JPW ) 83.23 Hz).
Phosphorus ylide (CO)5W--C(CH3)(H)P+Ph3 (25) was obtained
upon refluxing complex 7a (0.2 g, 0.46 mmol) and PPh3 (0.145 g, 0.55
mmol) in methylene chloride (10 mL) for 3 h. The solution turned
from orange to pale yellow. Evaporation of the solvent followed by
silica gel chromatography first gave with petroleum ether/dichlo-
romethane (80/20) as eluents complex 25 (0.2 g, 72%) and then with
petroleum ether/methylene chloride (40/60) complex 7a (0.045 g).
Spectral data for 25: yellow crystals, mp 109 °C; 1H NMR (CDCl3) δ
2
7.79-7.20 (m, 15H, PPh3), 2.47 (dq, 1H, JHP ) 14.4 Hz, JHH ) 7.0
2-[(Trimethylsilyl)oxy]-3-phenyltricyclo(3.2.1.02,4)octane (28c) was
obtained from complex 17 (0.30 g, 0.6 mmol) and 2-[(trimethylsilyl)-
oxy]bicyclo(2.2.1)hept-2-ene (4.9 mmol)50 in dichloromethane at room
temperature for 24 h. Workup as above gave 28c as an oil (0.16 g,
Hz, CH), 1.97 (dd, 3H, 3JHP ) 22.7 Hz, JHH ) 7.0 Hz, CH3); 13C NMR
(CDCl3) δ 202.02 (CO), 200.78 (CO), 133.40-124.31 (PPh3), 22.52
(d, JCP ) 3.0 Hz, CH3), -12.21 (d, JCP ) 15.2 Hz, CH); 31P (CDCl3)

12056 J. Am. Chem. Soc., Vol. 118, No. 48, 1996
Rudler et al.
98%). Spectral data for 28c (2.5:1 mixture of two isomers): 1H NMR
(CDCl3) δ 7.28-7.09 (m, 5H, Ar), 2.50-2.20 (m, 2H, C(1)-H and
C(5)-H), 2.18 (d, 1H, J ) 3.7 Hz, CHPh), 2.00-1.00 (m, 6H, 3CH2),
0.9-0.5 (m, 1H, C(4)-H), 0.25 and -0.16 (s, 9H, SiMe3); 13C NMR
(CDCl.) δ 140.5, 139.74, 128.85, 126.03, 125.41 (Ar), 67.78 and
65.80 (C(2)), 43.13 and 42.32 (C(1)), 37.13 and 36.89 (C(5)), 33.07
and 31.68 (C(8)), 30.75 and 30.44 (C(6)), 29.12 and 28.90 (C(7)), 25.66,
25.23, 25.12, 1.34 and 0.7 (SiMe3); MS calcd (obsd) for C17H24OSi+
272 (272).
(1r,2â,5r)-2-Benzylbicyclo(3.1.0)hexane (31b), 2-Benzyl-hexa-1,5-
diene (32b), and 5-Benzylhex-1-ene (33b). A mixture of 1,2- and
1,4-dihydropyridines prepared from N-carbomethoxydihydropyridines
(2.78 g, 2 × 10-2 mol) in diethyl ether (50 mL) as above was slowly
added to a solution of complex 30b (3.60 g, 6.66 × 10-3 mol) in diethyl
ether (50 mL) at 0 °C. The solution turned to dark orange and was
kept at room temperature for 10 h. Evaporation of the solvent followed
by silica gel chromatography of the residue gave with petroleum ether
as the eluent first a mixture of 32b and 31b (0.79 g) and then the diene
32b (0.20 g, 18%). Chromatography on silver nitrate impregnated silica
gel of the first fraction gave pure 31b as a liquid (0.5 g, 44%), then
the olefin 33b (0.06 g), and finally the diene 32b. Spectral data for
32b: 1H NMR (CDCl3) δ 7.36-7.21 (m, 5H, Ar), 5.85-5.77 (m, 1H,
CHdCH2), 5.85 (d, 1H, J ) 6.6 Hz, CHdCHH), 5.01 (d, 1H, J ) 1.6
Hz, CHdCHH), 4.88 (br s, 1H, CdCH), 4.81 (br s, 1H, CdCHh),
3.38 (s, 2H, PhCH2), 2.23 (m, 2H), 2.1 (m, 2H); 13C NMR (CDCl3) δ
148.43, 139.81, 138.44, 129.13, 128.41, 126.20, 114.70, 111.54 (Ar,
1-Methyl-1-acetoxy-3-phenylcyclopropane (28d) was obtained
from complex 17 (0.20 g, 0.4 mmol) and isopropenyl acetate (10 mL)
at room temperature for 12 h. Workup as above gave 28d as an oil
(0.050 g, 63%). Spectral data for 28d (cis/trans ) 73/27): 1H NMR
(CDCl3) δ (cis) 7.28 (m, 5H, Ar), 2.37 (dd, J ) 7.5 and 2.7 Hz, CHPh),
1.74 (s, 3H, CH3CO), 1.66 (s, 3H, CH3), 1.36-1.03 (m, 2H, CH2);
(trans) 7.30-7.12 (m, 5H, Ar), 2.16-2.09 (m, 1H, CHPh), 2.03 (s,
3H, CH3CO), 1.36-1.03 (m, 2H, CH2), 1.21 (s, 3H, CH3); 13C NMR
(CDCl3) δ (cis) 170.43 (CO), 137.09, 127.89, 127.80, 126.01 (Ar), 61.00
(C-O), 29.23 (CH3CdO), 22.20 (CH3), 20.91 (CHPh), 18.42 (CH2);
+
CHdCH2), 43.20 (PhC), 34.83, 32.00; MS calcd (obsd) for C13H16
172 (172). Spectra data for 33b: 1H NMR (CDCl3) δ 7.32-7.12 (m,
5H, Ar), 5.86-5.73 (m, 1H, CHdCH2), 5.04 (m, 1H, CHdCHH), 4.90
(m, 1H), 2.65 (dd, 1H, J ) 13.4 and 6 Hz, CHHPh), 2.33 (dd, 1H, J
) 13.4 and 8 Hz, CHHPh), 2.10 (m, 2H, CH2Cd), 1.73 (m, 1H,
CHCH3), 1.48 (m, 1H, CHCHH), 1.26 (m, 1H, CHCHH), 0.85 (d, 3H,
J ) 6.8 Hz, CHCH3); 13C NMR (CDCl3) δ 141.48, 139.14, 129.23,
128.13, 125.68, 114.25, (Ar, CHdCH2), 43.63 (+PhC), 35.88 (CH2),
+
HRMS calcd (obsd) for C12H14O2 190.0993 (190.0993).
2-[(Trimethylsilyl)oxy]-3-methyltricyclo(3.2.1.02,4)octane (28e) was
obtained from complex 7a (0.50 g, 1.16 mmol) and 2-[(trimethyl-
silyl)oxy]bicyclo(2.2.1)hept-2-ene (1.65 g, 9 mmol) in reluxing ben-
zene for 12 h. Workup as above gave compound 28e (0.11 g,
28%). Spectral data for 28e (1/4 mixture of endo/exo-cyclopropyl-
endo-methyl isomers): 1H NMR (CDCl3) δ (endo) 2.31-2.30 (1H, m,
C(1)-H), 2.17-2.16 (m, 1H, C(5)-H), 1.97-1.90 (m, 2H, C(7)-H2),
1.55-0.98 (m, 4H, C(6)-H2 and C(8)-H2), 0.98 ((s, 3H, CH3), 0.98-
0.80 (m, 1H, C(4)-H), 0.74-0.68 (dd, 1H, C(3)-H), 0.13 (s, 9H, SiMe3);
(exo) 2.33-2.32 (m, 1H, C(1)-H), 2.30-2.19 (m, 1H, C(5)-H), 1.97-
1.90 (m, 2H, C(7)-H2), 1.55-0.9 (m, 4H, C(6)-H2 and C(8)-H2), 0.98-
0.80 (m, 1H, C(4)-H), 0.74-0.68 (dd, 1H, C(3)-H), 0.23 (s, 3H, CH3),
0.13 (s, 9H, SiMe3); 13C NMR (CDCl3) δ 65.5 (C(2)), 42.5 (C(1)),
36.4 (C(5)), 29.2 (C(4)), 28.6 (C(6)), 24.7 (C(7)), 19.9 (C(3)), 12.0
(C(3)), 1.0 (SiMe3); HRMS calcd (obsd) for C12H22OSi+ 210.1439
(210.1430).
+
34.53 (CH), 31.45 (CH2), 19.32 (CH3); HRMS calcd (obsd) for C13H10
174.14085 (174.14078). Spectral data for 31b (1/1 mixture of
isomers): 1H NMR (CDCl3) δ 7.15-7.01 (m, 10H, Ar), 2.50-2.12
(m, 6H), 1.59-1.51 (m, 5H), 1.18-1.02 (m, 6H), 0.64-0.56 (m, 1H),
0.16-0.011 (m, 4H); 13C NMR (CDCl3) δ 142.0, 141.8, 129.24, 128.87,
125.72, 125.62 (Ar), 42.30, 41.77, 40.20, 27.46, 26.72, 25.18, 21.81,
+
20.68, 16.70, 16.10, 6.66, 3.29; HRMS calcd (obsd) for C13H16
172.1252 (172.1252).
(1-Ethoxy-2-cinnamylhex-5-enylidene)pentacarbonyltungsten-
(0) (30c) was obtained as above from complex 30a (4.5 g, 10 mmol)
and cinnamyl bromide (2.22 mL, 15 mmol) as an orange oil (2.55 g,
45%): 1H NMR (CDCl3) δ 7.33-7.31 (m, 5H, Ar), 6.37 (d, 1H,
J ) 15.8 Hz, CHPh), 6.17 (dt, 1H, J ) 15.8 and 17.6 Hz), 5.78 (m,
1H, CHdCPh), 4.98-5.06 (m, 2H, CdCH2), 4.94 (q, 2H, OCH2),
4.16 (m, 1H, CH), 2.46 (m, 1H CHH), 2.22 (m, 2H, CH2), 2.06 (m,
1H, CHH), 1.70 (m, 1H, CHH), 1.62 (t, 3H, CH3), 1.46 (m, 1H,
CHH); 13C NMR (CDCl3) δ 339.02 (WdC), 203.21 and 197.41 (CO),
138.11, 137.26, 132.54, 128.58, 127.32, 126.92; 126.11, 115.24
(CHdCH, Ar), 80.65 (OCH2), 71.9 (WdCC), 35.54, 31.77, 31.14
1-Ethoxy-1-phenyl-2-methylcyclopropane (28f) was obtained from
complex 7a (0.50 g, 1.16 mmol) and acetophenone ethyl enol ether
(0.45 g, 2.3 mmol) in benzene at 50 °C for 3 days. Workup as above
gave 28f as an oil (0.065 g, 31%). Spectral data for 28f (2.2:1 mixture
of isomers): 1H NMR (CDCl3) δ 7.33-7.29 (m, 5H, Ar), 3.58-3.32
(m, 2H, OCH2), 1.31 and 1.29 (2s, 6H, 2CH3), 1.20-1.16 (t, 6H,
2OCH2CH3), 0.93-0.82 (m, 1H, CHCH3), 0.78-0.70 (m, 1H, CHCH3);
HRMS calcd (obsd) for C12H16O+ 176.1201 (176.1181).
(1-Ethoxy-3-phenylprop-2-enylidene)pentacarbonyltungsten(0) (29)
was obtained upon stirring complex 17 (0.3 g, 0.6 mmol) with
ethoxyacetylene (0.5 g, 50% by weight in hexane, 3.6 mmol) in
methylene chloride (10 mL) for 1 h at room temperature. Evaporation
of the solvent followed by silica gel chromatography gave with
petroleum ether as the eluent complex 29 (0.017 g, 6%) as a red solid.
Its physical data were in all respect identical with those of an authentic
sample prepared in the laboratory. The same result was obtained by
carrying out the reaction at -78 °C.
(1-Ethoxy-2-benzylhex-5-enylidene)pentacarbonyltungsten(0) (30b).
Complex 30a (9.0 g, 2 × 10-2 mol) in THF (160 mL) was cooled to
-78 °C. A solution of BuLi (13.8 mL, 1.6 M) in hexanes was then
slowly added followed by benzyl bromide (2.6 mL, 2.2 × 10-2 mol).
The solution was then warmed to room temperature over 1 h.
Evaporation of the solvents followed by the addition of silica gel (15
g) gave a slurry which was put on a column of silica gel. Elution with
petroleum ether first gave the unreacted starting complex 30b con-
taminated with benzyl bromide (3.31 g). Elution with petroleum ether/
methylene chloride (95/5) gave complex 30b as a yellow oil (3.63 g,
33.6%). Spectral data for 30b: 1H NMR (CDCl) δ 7.31-7.05 (m,
5H, Ar), 5.78-5.61 (m, 1H, CHdCH2), 5.01-4.85 (m, 4H, CHdCH2,
OCH2), 4.21 (dt, J ) 6.4 Hz, WdCsCH), 2.92 (dd, 1H, PhsCH),
2.44 (dd, 1H, PhCH), 2.03 (m, 2H, CH2CHd), 1.64 (m, 1H,
-CHsCHH), 1.62 (t, 3H, CH3), 1.40 (m, 1H, CHsCHH); 13C NMR
(CDCl3) δ 339.44 (WdC), 203.10 (CO), 197.31 (CO), 139.02, 138.13,
129.31, 128.53, 128.40, 126.50, 115.18 (Ar, CdC), 80.60 (OCH2), 75.65
(dCsCH), 37.81, 31.73, 31.18, 14.67; HRMS calcd (obsd) for C20H20-
OW+ 540.0769 (540.0767).
+
(3CH2), 14.74 (CH3); HRMS calcd (obsd) for C22H23WO6 566.0925
(566.0924).
(1r,2â,5r)-2-(3-Phenyl-2-propenyl)bicyclo(3.1.0)hexane (31c) and
2-(3-phenyl-2-propenyl)-1,5-hexadiene (32c) were obtained from
complex 30c (2.2 g, 3.88 mmol) and N-carbethoxydihydropyridine (3
equiv) as above in diethyl ether (30 mL) first at 0 °C and then at room
temperature for 22 h. Evaporation of the solvent under vacuum
followed by silica gel chromatography gave first with petroleum ether
as eluent a mixture of 31c and 32c and then with the same eluent the
starting complex 30c (0.24 g). Chromatography on silver nitrate
impregnated silica gel first gave 31c as an oil (0.30 g, 40%), then 31c
and 32c (0.1 g), and finally 32c as an oil (0.060 g, 8%). Spectral data
for 31c (1/1 mixture of isomers): NMR (CDCl3) δ 7.77-7.18 (m, 10H,
Ar), 6.45-6.18 (m, 4H, CHdCH), 2.30-0.79 (m, 18H), 0.34-0.12
(m, 4H, CH2 cyclopropane); 13C NMR (CDCl3) δ 138.06, 137.93,
130.74, 130.65, 129.96, 128.50, 126.83, 126.77, 125.98 (Ar, CdC),
40.45 and 40.06 (2CH), 39.27 and 37.39 (2CH2), 27.50, 26.53, 25.44,
25.38 (CH2), 21.89 and 20.77 (CH cyclopropane), 16.58 and 16.28 (CH
cyclopropane), 6.82 and 3.40 (CH2); HRMS calcd for C15H18 198.1408
(M+), measd 198.1408. Spectral data for 32c: 1H NMR (CDCl3) δ
7.35-7.25 (m, 5H, Ar), 6.42 (d, 1H, J ) 15.7 Hz, dCHPh), 6.28-
6.14 (m, 1H, CHdCHPh), 5.90-5.73 (m, 1H, CHdCH2), 5.08-4.94
(m, 2H, CHdCH2), 4.83 (m, 2H, CdCH2), 2.92 (d, 2H, J ) 6.9 Hz,
CCH2Cd), 2.19 (m, 4H, 2CH2); 13C NMR (CDCl3) δ 147.77 (CdCH2),
138.42 (CHdCH2), 137.74 (Ar), 131.59 (dCHPh), 128.60 (Ar), 128.33
(CHdCHPh), 127.12 (Ar), 126.17 (Ar), 114.72 (CHdCH2), 110.67
+
(CdCH2), 40.09, 35.45, 32.02 (3CH2); HRMS calcd for C15H18
198.1408 (198.1408).

Dihydropyridines in Organometallic Synthesis
J. Am. Chem. Soc., Vol. 118, No. 48, 1996 12057
(1r,5r,6r)-6-Pentylbicyclo(3.1.0)hexane (31d) was obtained from
complex 30d (1.5 g, 2.88 mmol) and dihydropyridine obtained from
N-carbethoxydihydropyridine (3 equiv) first at 0 °C, then at room
temperature for 24 h, and finally at the reflux temperature of diethyl
ether for 1 h. Evaporation of the solvent followed by silica gel
chromatography first gave 31d (0.3 g, 70%) and then the starting
complex 30d (0.28 g). Spectral data for 31d: 1H NMR (CDCl3) δ
1.75-1.60 (m, 4H, C(2)-H2 and C(4)-H2), 1.53 (m, 1H, C(3)-H), 1.34-
1.28 (m, 6H, C(8)-H2, C(9)-H2 and C(10)-H2), 1.15 (m, 2H, C(7)-H2),
1.10 (m, 1H, C(3)-H), 0.95 (m, 2H, C(1)-H and C(5)-H), 0.91 (t, 3H,
CH3), 0.44 (hep, 1H, J ) 3.1 and 6.2 Hz, C(6)-H); 13C NMR (CDCl3)
δ 33.83 (C(7)), 31.88 and 29.40 (C(8) and C(9)), 27.66 (C(2) and C(4)),
24.39 (C(1) and C(5)), 22.69 (C(10)), 21.70 (C(3)), 19.16 (C(6)), 14.13
22.5 (CH2), 14.7 (OCCH3), 14.0 (CH3); HRMS calcd (obsd) for
C27H32O6W+ 636.1708 (636.1708).
[1-Ethoxy-2-(methoxymethyl)undec-5-enylidene]pentacarbonyl-
tungsten(0) (30g) was obtained as above by alkylation of complex
30d (1.8 g, 3.46 mmol) with chloromethyl methyl ether (2.4 mL, 3.8
1
mmol) in the presence of BuLi: yellow oil (0.7 g, 35%); H NMR
(CDCl3) δ 5.41-5.32 (m, 2H, CHdCH), 4.89 (q, 2H, OCH2), 4.28
(m, 1H, CH), 3.50 (dd, 1H, J ) 9.3 and 7.5 Hz, OCHH), 3.30 (dd, 1H,
J ) 9.3 and 5.5 Hz, OCHH), 3.26 (s, 3H, OCH3), 2.07-1.90 (m, 4H,
dCCH2), 1.58 (t, 3H, CH3), 1.38-1.19 (m, 8H, 4CH2), 0.86 (t, 3H,
CH3); 13C NMR (CDCl3) δ 337.74 (WdC), 200.51 and 197.35 (CO),
131.72 and 129.10 (CHdCH), 80.62 (OCH2), 73.75 (OCH2), 59.17
(OCH3), 32.57, 31.45, 30.63, 29.95, 29.22, 22.58 (CH2), 14.72, 14.09
(CH3); MS calcd (obsd) for C13H28O6W (M - CO)+ 536.1395
(536.1395).
+
(CH3); HRMS calcd (obsd) for C11H20 152.1565 (152.1565).
(1r,2r,5r,6r)-6-Pentyl-2-benzylbicyclo(3.1.0)hexane (31e) and
2-benzylundec-1,5-diene (32e) were obtained as above from complex
30e (1.2 g, 2 mmol) and dihydropyridine (3 equiv) as above first at 0
°C then at room temperature for 12 h. Workup and purification as
above gave starting carbene complex 30e (0.25 g), compound 31e (0.185
g, 40%) as an oil, and the diene 32e (0.070 g). Spectral data for 31e:
1H NMR (CDCl3) δ 7.32-7.20 (m, 5H, Ar), 2.64 (d, 1H, J ) 3.6 Hz,
CHHPh), 2.35 (m, 1H, H-2), 1.74 (m, 1H, H-4′), 1.67 (m, 1H, H-4),
1.53 (m, 1H, H-3), 1.39-1.27 (m, 6H, 3CH2-8,9,10), 1.19 (m, 1H, H-7),
1.11 (m, 1H, H-7′), 0.95 (m, 1H, H-5), 0.92 (m, 3H, CH3), 0.89 (m,
1H, H-1), 0.84 (m, 1H, H-3′), 0.62 (m, 1H, H-6); 13C NMR (CDCl3) δ
132.90, 128.45, 127.72, 125.12 (Ar), 42.27 (C(2)), 39.80 (CH2Ph), 32.32
(C(7)), 31.43, 29.07 (2CH2), 28.00 and 27.95 (C(3) and C(5)), 27.22
(C(4)), 24.14 (C(1)), 22.38 (CH2), 16.30 (C(6)), 13.77 (CH3); HRMS
calcd for C18H26 242.2034 (M+), measd 242.2034. Spectral data for
32e: 1H NMR (CDCl3) δ 7.33-7.20 (m, 5H, Ar), 5.43-5.38 (m, 2H,
CHdCH), 4.76 (s, 1H, CdCHH), 3.36 (s, 2H, CH2Ph), 2.14 (m, 2H,
CH2CdC), 2.06 (m, 2H, CH2Cd), 1.87 (m, 2H, CH2Cd), 1.37-1.25
(m, 6H, 3 CH2), 0.90 (t, 3H, CH3); 13C NMR (CDCl3) δ 148.72
(CdCH2), 139.86 (Ar), 130.91 (dCH), 129.52 (dCH), 129.10 (Ar),
128.31 (Ar), 126.09 (Ar), 11.30 (CdCH2), 43.20 (CH2Ph), 35.50, 32.62,
31.47 (3 CH2Cd), 30.83, 29.34, 22.64 (3CH2), 14.18 (CH3); HRMS
(1r,2r,5r,6r)-6-Pentyl-2-(3-phenyl-2-propenyl)bicyclo(3.1.0)-
hexane (31f) and 2-(3-phenyl-2-propenyl)undec-1,5-diene (32f) were
obtained as above from complex 30f (1.8 g, 2.8 mmol) and dihydro-
pyridine (2 equiv). Workup followed by silica gel chromatography
gave 31f as an oil (0.27 g, 35%) and then 32f (0.05 g, 7%). Spectral
data for 31f: 1H NMR (CDCl3) δ 7.40-7.20 (m, 5H, Ar), 6.42 (1H, d,
J ) 16 Hz, dCHPh), 6.35-6.27 (1H, m, dCHCH2), 2.27-2.21 (m,
3H, CH2 and H-2), 1.75-1.69 (m, 2H, H-4, H-4′), 1.63-1.60 (m, 1H,
H-3), 1.32-1.25 (m, 7H, H-7, H2-8,9,10), 1.03-1.00 (m, 3H, H-7′,
H-1, H-5), 0.94-0.90 (m, 3H, CH3), 0.87-0.79 (m, 1H, H-3′), 0.61-
0.56 (m, 1H, H-6); 13C NMR (CDCl3) δ 138.14, 130.83 (CH2CHd),
130.04 (PhCHd), 128.54 (Ar), 126.78, 125.97 (Ar), 40.76 (C(2)), 37.51
(CH2Cd), 32.75 (C(7)), 31.86 (CH2), 29.54 (CH2), 28.59 (C(5)), 28.26
(C(3)), 27.72 (C(4)), 24.54 (C(1)), 22.83 (CH2), 16.90 (C(6)), 14.23
(CH3); HRMS calcd (obsd) for C20H28+ 268.2191 (268.2191). Spectral
data for 32f: 1H NMR (CDCl3) δ 7.28 (m, 5H, Ar), 6.42 (d, 1H, J )
16 Hz, dCHPh), 6.24 (m, 1H, CHdCPh), 5.44 (m, 2H), 4.84 (m, 2H),
2.94 (m, 2H), 2.17 (m, 4H), 1.99 (m, 2H), 1.33 (m, 6H), 0.87 (t, 3H,
CH3); 13C NMR (CDCl3) δ 137.2, 132.4, 130.9, 128.6, 127.9, 127.8,
127.1, 126.4, 125.2, 39.4, 35.5, 32.0, 30.2, 28.7, 22.0, 18.9, 13.5; HRMS
+
calcd (obsd) for C20H28 268.2191 (268.2191).
+
(1r,2r,5r,6r)-(6-Pentyl-2-methylmethoxy)bicyclo(3.1.0)hexane
(31g) and 2-(methylmethoxy)undec-1,5-diene (32g) was obtained as
above from complex 30g (0.6 g, 1.06 mmol) and dihydropyridine at
room temperature for 4 h. Workup as usual gave first 32g (0.065 g,
33%) as an oil. Spectral data of 31g: 1H NMR (CDCl3) δ 3.37 (s,
3H, OCH3), 3.35-3.31 (m, 2H, OCHH), 2.39-2.34 (m, 1H, H-2),
1.74-1.69 (m, 2H, H-4,4′), 1.61-1.58 (m, 1H, H-3), 1.36-1.23 (m,
6H, CH2-8,9,10), 1.22 (m, 1H, H-7), 1.02 (m, 2H, H-1, H-5), 0.89 (m,
3H, CH3), 0.79-0.70 (m, 1H, H-3′), 0.54-0.49 (m, 1H, H-6); 13C NMR
(CDCl3) δ 76.64 (OCH2), 58.97 (OCH3), 40.50 (C(2)), 31.53 and 31.74
(C(7), C(8)), 29.40 (C(9)), 27.43 (C(4)), 26.84 and 24.37 (C(1), C(5)),
25.65 (C(3)), 22.79 (C(10)), 16.88 (C(6)), 14.18 (CH3); MS calcd (obsd)
for C13H24O+ 196 (196). Spectral data for 32g: 0.020 g, 10%, oil; 1H
NMR (CDCl3) δ 5.50-5.39 (m, 2H, CHdCH), 5.00 and 4.92 (br s,
2H, dCH2), 3.85 (s, 2H, OCH2), 3.32 (s, 3H, OCH3), 2.12 (m, 2H,
CH2), 1.96 (m, 4H, 2dCCH2), 1.30-1.25 (m, 6H, 3CH2), 0.88 (t, 3H,
CH3); 13C NMR (CDCl3) δ 145.77 (dC), 131.09 and 129.54 (2dCH),
111.72 (dCH2), 75.78 (OCH2), 57.99 (OCH3), 33.21, 32.66, 31.51,
30.84, 29.39, 22.69 (CH2), 14.20 (CH3); MS calcd (obsd) for C13H24O+
196 (196).
(1-Ethoxy-2-benzylpentylidene)pentacarbonyltungsten(0) (34) was
obtained as above from (1-ethoxypentylidene)pentacarbonyltungsten-
(0) (2.5 g, 5.75 mmol) and benzyl bromide (1.0 mL, 8.6 mmol), in the
presence of BuLi, as a yellow oil (1.4 g, 46%): 1H NMR (CDCl3) δ
7.40-7.10 (m, 5H, Ar), 4.92 (q, 2H, OCH2), 4.22 (m, 1H, CH), 2.90
(dd, 1H, J ) 13.3 and 7.1 Hz, CHHPh), 2.43 (dd, 1H, J ) 13.3 and
7.8 Hz, CHHPh), 1.62 (t, 3H, CH3), 1.60-1.15 (m, 4H, 2CH2), 0.85
(t, 3H, CH3); 13C NMR (CDCl3) δ 340.12 (WdC), 203.95 and 197.39
(CO), 139.27, 129.25, 128.55, 128.46, 126.03 (Ar), 80.65 (OCH2), 74.26
(CH), 38.00 (CH2Ph), 34.35 and 21.02 (CH2), 14.81 (2CH3); HRMS
calcd (obsd) for C19H20O6W+ 528.0769 (528.0767).
calcd (obsd) for C18H26 242.2034 (242.2034).
(1-Ethoxyundec-5-enylidene)pentacarbonyltungsten(0) (30d) was
obtained as above from the corresponding iodide (5.8 g, 22 mmol),
tBuLi (25.9 mL, 44 mmol), and W(CO)6 (7.75 g, 22 mmol) as a yellow
oil (4.5 g, 40%): 1H NMR (CDCl3) δ 5.50-5.35 (m, 2H, CHdCH),
4.87 (q, 2H, OCH2), 3.17 (m, 2H, WdCCH2), 2.02-1.91 (m, 4H, CH2-
CHdCHCH2), 1.60 (t, 3H, CH3), 1.61-1.50 (m, 2H, CH2), 1.36-1.22
(m, 6H, 3CH2), 0.86 (t, 3H, CH3); 13C NMR (CDCl3) δ 334.21 (WdC),
203.58 and 197.42 (CO), 132.06, 128.85 (2CdC), 80.68 (OCH2), 64.57
(WdCC), 32.60, 32.04 (CCdCC), 31.47, 29.26, 26.28, 22.59 (3CH2),
14.84 (OCH2CH3), 14.15 (CH3); HRMS calcd (obsd) for C18H24O6W+
520.1082 (520.1081).
(1-Ethoxy-2-benzylundec-5-enylidene)pentacarbonyltungsten-
(0) (30e) was obtained as above by alkylation of complex 30d (3 g,
5.77 mmol) with benzyl bromide (1.03 mL, 8.65 mmol) in the presence
of BuLi as a yellow oil (1.9 g, 55%): 1H NMR (CDCl3) δ 7.33-7.10
(m, 5H, Ar), 5.45-5.25 (m, 2H, CHdCH), 4.90 (q, 2H, OCH2), 4.23
(m, 1H, WdCCH), 2.90 (dd, 1H, J ) 13.3 and 6.6 Hz, CHHPh), 2.48
(dd, 1H, J ) 13.3 and 7.4 Hz, CHHPh), 2.07-1.89 (m, 4H,
CH2CHdCHCH2), 1.71-1.50 (m, 5H, CH2 and CH3), 1.41-1.18 (m,
6H, 3CH2), 0.89 (t, 3H, CH3); 13C NMR (CDCl3) δ 332.98 (WdC),
203.32 and 197.34 (CO), 139.18, 131.67, 129.34, 128.54, 126.48,
126.04 (CdC and Ph), 80.62 (OCH2), 73.61 (CH), 37.82 (CH2Ph),
32.64, 31.87, 31.54, 30.63, 29.33, 22.66 (6CH2), 14.80 (CH2CH3), 14.18
(CH3); MS calcd (obsd) for C25H30O6W+ 610.1551 (610.1550).
(1-Ethoxy-2-cinnamylundec-5-enylidene)pentacarbonyltungsten-
(0) (30f) was obtained as above from complex 30d (3.7 g, 7.9 mmol)
and cinnamyl bromide (1.6 g, 7.9 mmol) in the presence of BuLi as a
yellow oil (2.4 g, 50%): 1H NMR (CDCl3) δ 7.30-7.23 (m, 5H, Ar),
6.37 (d, J ) 16 Hz, PhCdCH), 5.37 (m, 2H, CHdCH), 4.90 (q, 2H,
OCH2), 4.13 (m, 1H, WdCCH), 2.46 and 2.22 (m, 2H, CH2Ph), 1.95
(m, 4H, CH2CdCCH2), 1.62 (t, 3H, OCH2CH3), 1.17 (m, 6H, 3CH2),
8.87 (t, 3H, CH3); 13C NMR (CDCl3) δ 333.0 (WdC), 203.2 and 197.4
(CO), 137.1, 128.6, 127.3, 126.1 (Ar), 132.2, 129.1, 127.1, 127.0
(CdC), 80.5 (OCH2), 71.7 (WdCC), 35.3, 32.5, 31.7, 31.4, 30.5, 20.1,
2-Benzylpent-2-ene (36) was obtained from complex 34 (1 g, 1.9
mmol) and dihydropyridine (2 equiv) at room temperature. Evaporation
of the solvent followed by chromatography gave with petroleum ether
as the eluent the olefin 36 (0.060 g, 33%) and then with the same eluent
complex 34 (0.4 g). Spectra data for 36: 1H NMR (CDCl3) δ 7.33-

12058 J. Am. Chem. Soc., Vol. 118, No. 48, 1996
Rudler et al.
7.20 (m, 5H, Ar), 4.84 and 4.75 (s, 1H, CdCHH), 3.35 (s, 2H, CH2-
Ph), 1.96 (t, 2H, J ) 7.5 Hz, CH2Cd), 1.48 (m, 2H, CH2), 0.90 (t, 3H,
CH3); 13C NMR (CDCl3) δ 149.08 (CdCH2), 140.01, 129.09, 128.33,
126.07 (Ar), 43.10 (CH2Ph), 37.64 (CH2CdC), 20.81 (CH2), 13.90
3H, J ) 6.9 Hz, CH3), 0.67 (dddd, 1H, J ) 7.12 Hz, H-6); 13C NMR
(CDCl3) δ 32.27 (C(10)), 30.46 (C(9)), 27.56 (C(3)), 25.45 (C(3)), 25.45
(C(2), C(4)), 23.90 (C(7)), 23.11 (C(8)), 22.59 (C(1), C(5)), 21.66
(C(6)), 14.48 (C(11)); HRMS calcd (obsd) for C11H20 152.1565
(152.1564).
+
+
(CH3); HRMS calcd (obsd) for C12H16 160.1252 (160.1252).
(1-Ethoxyundec-5(E)-enylidene)pentacarbonyltungsten(0) (30d′)
was obtained as 30d from the corresponding iodide as a yellow oil
(35%): 1H NMR (CDCl3) δ 5.50-5.30 (m, 2H, HCdCH), 4.89 (q,
2H, J ) 7.1 Hz, OCH2), 3.20 (m, 2H, WdCCH2), 2.10-1.95 (m, 4H,
2dCCH2), 1.61 (t, 3H, J ) 7.1 Hz, CH3), 1.60-1.45 (m, 2H, CH2),
1.40-1.20 (m, 6H, 3CH2), 0.80 (t, 3H, J ) 6.9 Hz, CH3); 13C NMR
(CDCl3) δ 334.04 (WdC), 203.37 and 197.39 (CO), 131.41 and 128.26
(CdC), 80.69 (OCH2), 64.70 (WdCC), 31.55, 29.44, 27.28, 26.65,
22.61 (CH2), 14.79 and 14.11 (CH3); HRMS calcd (obsd) for
C18H24O6W+ 520.1082 (520.1081).
(1r,5r,6â)-6-Pentylbicyclo(3.1.0)hexane (31d′) was obtained as
above from complex 30d′ (0.7 g) and dihydropyridines (3 equiv) as an
oil (0.120 g, 60%): 1H NMR (CDCl3) δ 1.90-1.80 (m, 2H, H-4 and
H-2), 1.80-1.75 (m, 1H, H-3), 1.60-1.53 (m, 2H, H-4 and H-2), 1.43-
1.25 (m, 9H, H-1,3,5,8,9,10), 1.17 (dt, J ) 7.1 Hz, CH2-7), 0.90 (t,
Acknowledgment. This research was kindly supported by
the Commission of the European Communities (DGSRD,
International Scientific Cooperation), Centre National de la
Recherche Scientifique, and Ministerio de Educacion y Ciencia
(Spain) (posdoctoral research grant to M.B.V.). Professor N.
Platzer (University P. M. Curie, Paris) is especially acknowl-
edged for carrying out the NMR experiments.
Supporting Information Available: Tables of fractional
parameters and anisotropic thermal parameters for complexes
7a and 8a (4 pages). See any current masthead page for
ordering and Internet access instructions.
JA9622057