Tungsten(0) alkylidene complexes stabilized as pyridinium ylides: New aspects of their synthesis and reactivity

Article abstract of DOI:10.1016/S0022-328X(00)00727-0

The interaction of dihydropyridines with alkoxycarbene complexes of tungsten has been shown to lead to pyridinium ylid complexes: this transformation has now been applied to the synthesis of a hydroxyl-containing ylid complex by ring-opening of the pentacarbonyl (2-oxacyclopentylidene) tungsten(0) complex and to the synthesis of a series of chiral ylid complexes both from chiral and non-chiral carbene complexes by the use of dihydropyridines and dihydronicotines, respectively. The transfer of the alkylidene moiety of these complexes to nucleophilic olefins will be outlined and discussed. Especially relevant is the interaction of these pyridinium ylid complexes with unsaturated substrates such as dihydropyridines, enamines, and β-alkoxy bis(trimethyl-silyl) ketene acetals. This latter reaction leads to conjugated carboxylic acids, and has been be applied to a new synthesis of a honey bee pheromone, the queen substance.

Full text of DOI:10.1016/S0022-328X(00)00727-0

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 617–618 (2001) 571–587
Tungsten(0) alkylidene complexes stabilized as pyridinium ylides:
new aspects of their synthesis and reactivity
Henri Rudler *, Thomas Durand-Re´ville
Laboratoire de synthe`se Organique et Organome´tallique, UMR 7611,
Uni6ersite´ Pierre et Marie Curie T 44-45 4 place Jussieu 75252 Paris Cedex 5, France
Received 16 August 2000; accepted 28 September 2000
Abstract
The interaction of dihydropyridines with alkoxycarbene complexes of tungsten has been shown to lead to pyridinium ylid
complexes: this transformation has now been applied to the synthesis of a hydroxyl-containing ylid complex by ring-opening of
the pentacarbonyl (2-oxacyclopentylidene) tungsten(0) complex and to the synthesis of a series of chiral ylid complexes both from
chiral and non-chiral carbene complexes by the use of dihydropyridines and dihydronicotines, respectively. The transfer of the
alkylidene moiety of these complexes to nucleophilic olefins will be outlined and discussed. Especially relevant is the interaction
of these pyridinium ylid complexes with unsaturated substrates such as dihydropyridines, enamines, and b-alkoxy bis(trimethyl-
silyl) ketene acetals. This latter reaction leads to conjugated carboxylic acids, and has been be applied to a new synthesis of a
honey bee pheromone, the queen substance. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Tungsten; Pyridinium ylid complexes; Dihydropyridines; Dihydronicotines; Cyclopropanes; Conjugated carboxylic acids
In these two examples, stabilization towards decompo-
sition is provided by internal interactions.
1. Introduction
As far as the metal carbenes of the Fischer type are
concerned, stabilization occurs both by internal and by
external interactions since [7] the s-orbital electrons of
the organic carbene interact with an empty orbital of
the M(CO)5 fragment, whereas both the doublet on the
oxygen atom of the alkoxy group and electrons of a
d-orbital of the metal interact with the empty p–p
orbital of the carbene carbon.
Singlet carbenes which are not substituted by a het-
eroatom can also be stabilized with respect to their
decomposition products. It has been found by Jackson
and Platz [8] that a unique way to make visible, and to
stabilize carbenes arising from diazo compounds 1 via
Laser Flash Photolysis (LFP), towards intramolecular
and intermolecular decay channels is to react them, at
low temperature, with pyridine. The interaction of the
nonbonding pair of electrons of the heterocycle with
the empty p-orbital of the carbene 2 yields indeed a
pyridinium ylid (Eq. (1)) [9].
The synthesis of ‘bottleable’ carbenes stable enough
to be used as such or as metal-bound ligands is still an
unabated matter of research. Interest in such species
arose upon the discovery of their involvement in reac-
tions such as the olefin metathesis, first in industrial
processes, more recently for the synthesis of fine chemi-
cals [1], in the stoichiometric and catalytic versions of
the olefin cyclopropanation reaction [2], in the activa-
tion of carbonꢀhydrogen bonds [3], and finally in their
use as ‘neutral’ ligands in various catalytic systems [4].
Since our interest is mainly in carbene complexes of
the Fischer type, the association of singlet carbenes and
a metal fragment M(CO)5, let us first consider singlet
carbenes. They are stabilized relatively to their decom-
position products when their substituents have a struc-
ture such that a flow of electrons to and from the
carbene carbon can occur. This appears clearly in the
carbenes prepared by Bertrand [5] and by Arduengo [6].
* Corresponding author. Tel.: +331-44-275092; fax: +331-44-
275504.
E-mail address: rudler@ccr.jussieu.fr (H. Rudler).
(1)
0022-328X/00/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00727-0

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Moreover, further stabilization occurs when delocal-
ization of the remaining ‘negative’ charge of the car-
bene is achieved. For instance, Singer [11] and
Zugravescu [12], synthesized the tetraphenylcyclopenta-
dienylidene pyridinium ylid 5 from 4 and Wentrup [10]
described the low temperature transformation of 6 into
7 (Eq. (2)).
(5)
The purpose of this paper is first to provide addi-
tional data in order to elucidate the mechanism of the
reduction of various alkoxycarbene complexes of tung-
sten with dihydropyridines; second, to describe the
synthesis of chiral ylid complexes starting either from
chiral carbene complexes or from chiral dihydropyridi-
nes and preliminary results on the transfer of the vari-
ous alkylidene groups on olefines; third, to describe a
typical reaction of carbene complexes, the insertion into
a carbonꢀhydrogen bond; and finally, to disclose new
applications of these complexes to the synthesis of
highly functionalized cyclopropanes which can lead,
depending on the substituents of the olefines, to a,b-un-
saturated carboxylic acids. Application to the prepara-
tion of a honey bee pheromone, the queen substance,
will be outlined.
(2)
Examples of ylides stabilized with respect to decom-
position with a metal fragment, had already been de-
scribed. For example, the interaction of platinum(II)
complexes of pyridine 8 with diazo compounds allowed
indeed Mason [13] and later on Jennings [14], to isolate
platinum pyridinium ylid complexes 9 (Eq. (3)).
2. Results and discussion
The discovery of the possible reduction of Fischer-
type carbene complexes with dihydropyridines opened a
new field of investigations for these complexes. We
demonstrated indeed that dihydropyridines act as a
source of a hydride and of a proton during their
interaction with these complexes (Eqs. (5,6)).
(3)
A similar approach led to related phosphorus ylid
complexes: Kreissl [15] and Casey [16] described the
interaction of pentacarbonyldiphenyltungsten(0) car-
bene and pentacarbonyl phenyltungsten(0) carbene 10
with phosphines giving very stable phosphorus ylid
complexes 11: the electron withdrawing M(CO)5 be-
haves here like the carbonyl group in the acylium
N-ylides (Eq. (4)).
(4)
(6)
Examples can also be found for iron and osmium
complexes isolated by Cutler [17], Helquist [18] and
Woo [19].
Overall, and as shown in Eq. (6), a hydride is trans-
ferred to the electrophilic carbene carbon of alkoxycar-
bene complexes 12 to give the pyridinium metallates 15;
this is followed by a proton-assisted elimination of
ethanol, which leads to alkylidene complexes of
chromium or tungsten pentacarbonyl 16 and to pyri-
dine. These alkylidene complexes are not stable relative
to their decomposition products (dimers, olefines) and
since they contain an electrophilic carbene carbon, in-
teraction with pyridine occurs and gives rise to new
pyridinium ylid complexes 14. Most importantly, this
approach is of a general scope. The new complexes are
air-stable, can be purified by silica gel chromatography,
By taking advantage of the similarity which exists
between Fischer carbene complexes and carbonyl
groups, we have recently developed an original, one-
step approach to such pyridinium ylid complexes: a
biomimetic reduction of alkoxycarbene complexes 12 of
tungsten and chromium with dihydropyridines 13 led
indeed in one step to (pentacarbonyl) tungsten and
chromium pyridinium ylid complexes 14 [20]. In these
complexes an organic carbene, devoid of a heteroatom
substituent, is linked to pyridine and to a M(CO)5
fragment (Eq. (5)).

H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
573
and have been fully characterized by their spectroscopic
data and also by X-ray crystallography. By far the most
impressive modification is the upfield shift of the signal
assigned to the former carbene carbon from 333 to 57
ppm (M=W, R=Me).
2.1. Mechanism of the hydride transfer: synthesis of
pyridinium metallates and functionalized pyridinium ylid
complexes
(8)
At first sight, evidence for a direct hydride transfer
exists although the possible rearrangement of such a
carbene carbon centered radical has to be confirmed
electrochemically.
The transformation described above has already been
thoroughly examined [21,22]. However, several aspects
of the mechanism leading to the new complexes re-
mained unraveled, e.g. the detailed mechanism of the
first step, the overall hydride transfer from dihydropy-
ridine to the carbene carbon.
The cyclopropylmethylene group could in turn be
transferred quantitatively without rearrangement to the
double bond of the enamine of cyclopentanone to give
the double cyclopropane-containing product 19, confir-
ming that no free carbene is involved in this reaction [25].
Related to this point is the structure of the first
intermediate, the alkoxyalkyl (pentacarbonyl) pyri-
dinium tungstate or chromate 15. The problem of its
structure was settled in the following way: the reaction
between N-methyldihydropyridine 20 and the alkoxycar-
bene complex 12 led indeed to the tungstate 21 which
could be characterized by NMR. No proton is available
in this case to promote the ethanol elimination. Rather
then undergoing an elimination of alcohol, transforma-
tions expected for carbonyl-containing alkyl metallates
were observed, e.g. the insertion of a CO group leading
to new pyridinium acylmetallates 22 [22] (Eq. (8)).
Dihydropyridines are involved in many enzymic
transformations: for example dihydronicotinamide
adenine dinucleotide (NADH) acts as a source of two
electrons and a proton, thus transferring a hydride to a
suitable substrate, for example a carbonyl group [23].
Depending on the nature of the substrates, two main
possibilities have been discussed for these transfers: a
concerted hydride transfer or a sequential electron–
proton–electron transfer. Let’s consider the alkoxycar-
bene complexes of tungsten: Krusic and Casey have
shown that these complexes, as analogues of organic
carbonyl groups, are susceptible to one electron reduc-
tions [24] leading to a carbene carbon centered radical.
A possible way to detect such an intermediate if it were
formed during the interaction of dihydropyridines with
alkoxycarbene complexes of tungsten would be to carry
out the reaction on the carbene complex 17: a carbon
centered radical might indeed lead to ring opened prod-
ucts and thus provide evidence for a single electron
transfer. However, this reaction exclusively gave the
pyridinium ylid complex 18 as yellow crystals, in 48%
1
yield (Eq. (7)). The H-NMR spectrum confirmed the
presence of the proton on the former carbene carbon,
giving a doublet at l 3.91, and the signals for the five
hydrogens of the cyclopropyl group at l 2.01, 1.03,
0.69, 0.53 and 0.10, whereas the 13C-NMR spectrum
exhibited a typical signal at l 70.8 for C(1).
(9)
The fate of the ethoxy group of the carbene complexes
could also be determined. Indeed, the reaction of the
pentacarbonyl (2-oxacyclopentylidene)tungsten complex
23 [26] with a mixture of dihydropyridines led to a 66%
yield of the ring-opened, hydroxyl-containing ylid com-
plex 26 as a yellow solid via 24 and 25 (Eq. (9)). The
NMR spectra confirmed on the one hand the presence
among others, of a signal for the proton on the former
carbene carbon at l 4.65 as a doublet of doublets
(13C-NMR, l 63.9), at l 3.65 for the OCH2 protons, and
at l 2.07 as a broad signal for the proton of the hydroxyl
group.
(10)
(7)

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This new complex is stable and no interaction between
2.2. Synthesis and reacti6ity of new pyridinium ylid
the hydroxyl group and the ylid carbon could be de-
tected. The transformation of 23“26 opens the field of
the preparation of functionalized pyridinium ylid com-
plexes, potential precursors of d-hydroxycarbenes and
thus to the possible access to new functionalized cyclo-
propanes. (vide infra.)
complexes
Cyclopropanation of carbonꢀcarbon double bonds,
especially when enantioselective, is an important trans-
formation in organic synthesis [29,30]. For that purpose,
several possibilities exist among which either the transfer
of a carbene to an olefin by means of a chiral catalyst,
or for example, the transfer of a chiral carbene to an
olefin. For such a purpose we synthesized two types of
chiral pyridinium ylid complexes, one in which the chiral
center is part of the carbene to be transferred, the other
one in which the chiral group belongs to the pyridine,
thus to the leaving group.
2.1.1. Thermolysis of the pyridinium ylid complexes:
insertion into a CꢀH bond
The pyridinium ylid complexes of the type 14 (R=Ph,
M=W) are thermodynamically very stable both in
solution upon exclusion of air and in the solid state. No
release of pyridine with decomposition of the alkylidene
moiety was observed at room temperature Eq. (10).
According to previous observations [35], their behav-
ior towards olefines is quite different from that of the
known pentacarbonylbenzylidene tungsten(0) complex:
carbonꢀcarbon double bonds interact as nucleophiles
with these ylide complexes to give open chain, dipolar
intermediates with elimination of pyridine. An in-
tramolecular cyclization leads then to cyclopropanes.
The first step of these transformations is thus a substitu-
tion reaction: such a mechanism can also be linked to the
observation of a reversible electron transfer to these ylide
complexes and thus to the existence of an available
low-lying unoccupied orbital for such an interaction.
A similar mechanism could account for the transfor-
mation of THF upon its reaction with complex 27. No
reaction took place at room temperature. However, at
reflux temperature of THF, a fast formation of a-benzyl
tetrahydrofurane 31 in 84% yield was observed. It is
likely that the first step is the formation of the ylid
complex 28, a structure which has also been suggested
by H. Fischer in the case of the interaction of the
(pentacarbonyl)benzylidene tungsten(0) with THF. This
then rearranges to 31 via 29 and 30 [27,28].
2.2.1. Successi6e syntheses of two chiral carbene and
ylid complexes
The synthesis of the two chiral carbene complexes 35
and 37 was straightforward from the chiral organo-
lithium derivatives. Their physical data can be found in
Section 4.
These carbene complexes were reduced as above with
a mixture of dihydropyridines at room temperature to
give the expected ylid complexes 36 and 38 in 78 and 90%
yields, respectively (Eqs. (12, 13)). Complex 36, obtained
as a yellow solid, was a mixture of two diastereomers
(de=6%) according to the 1H-NMR spectra which
disclosed signals for the two different C(1)ꢀH protons at
l 4.91 and 4.85 as a doublet of doublets: the reduction
took thus place with a low diastereoselectivity. The
situation was more complicated in the case of the ylid
complex 38 since the presence of the diastereoisomers A
and B (de=10%) could only be established by 13C-NMR
(l C(1) 65.1 for A, 64.7 for B): no chemical shift
1
differences were seen in the H-NMR spectrum.
Complex 32 behaved however differently: no reaction
took place at room temperature, but when the thermol-
ysis was conducted in refluxing diethyl ether, then a 65%
yield of the olefin 33 resulting from the rearrangement
of the alkylidene group was obtained (Eq. (12)). No
product due to the insertion of the alkylidene group into
a CꢀH bond of diethyl ether could be detected [27,28].
It is likely that in this latter case the less nucleophilic
diethyl ether allowed a metal assisted elimination of
pyridine to occur as depicted in Eq. (11).
(12)
(13)
(11)

H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
575
2.2.2. Reduction of the carbene complexes with
dihydronicotines
satile sources of alkylidene groups transferable to
various nucleophilic unsaturated substrates: the intro-
duction of the M(CO)5 fragment causes thus an umpol-
ung of the alkylidene group.
A second way to possibly introduce chiral centers
into the ylid complexes would be to use a chiral dihy-
dropyridine. Among the simplest chiral pyridines which
might lead to chiral dihydropyridines appears to be
(S)-nicotine 39 though, to the best of our knowledge,
its reduction to dihydronicotine has not been reported
in the literature. Due to the presence of two nitrogen
atoms which can be alkylated [31] no attempts were
made to use Fowler’ method of preparation of dihy-
dropyridines [32]. We therefore considered using direct
LiAlH4 reduction and indeed discovered that nicotine,
like pyridine, could easily be reduced by this reagent
into a mixture of nicotine and the isomeric dihydroni-
cotines 41. Their ethereal solutions reduced quantita-
tively, when used in a slight excess (see Section 4), a
series of carbene complexes.
Thus, complexes 40 and 43 gave instantaneously, at
room temperature, the nicotinium ylid complexes 42
and 44 in 72 and 47% yields, respectively, as orange oils
(Eq. (14)). Again, diastereoisomers could be detected by
1H-NMR, in the first case (de=10%) with signals for
C(1)ꢀH at l 4.88 and 4.87 as quartets, in the second
case by 13C-NMR, (de=10%) with signals for C(2) at l
50.5 and 50.4.
Let us first consider the transfer of the ethylidene
groups from the complexes 42 and 45 to the enamine of
cyclopentanone. We have established that, as in all the
cases examined so far, two exo:endo (62:38) isomers 46
and 47 separable by silica gel chromatography were
formed in 56% yield from complex 42 [35]. When the
same reaction was carried out on complex 45, almost
an identical mixture of isomers (54% yield, exo:endo=
67:33) was observed (Eq. (15)). According to NMR
experiments in the presence of a chiral shift reagent, no
enantiomeric enrichment was visible.
The exception came from 36 which led with the same
enamine to the aminocyclopropane 48 in 60% yield as
the single exo isomer (Eq. (16)), but according to the
NMR, as a mixture of two diastereoisomers (de=20%)
which gave separate signals in the 13C-NMR spectrum,
1
but not in the H-NMR spectrum, for example at l
55.5 and 55.2 for C(1) of each isomer.
Under the same conditions, and in the presence of
the same enamine, complex 38 gave a 60:40 mixture of
exo and endo isomers 49 in 79% yield (Eq. (17)). These
two isomers were separated by silica gel chromatogra-
phy. The 13C-NMR on each isomer allowed again to
determine the diastereoselectivity of the transfer (de=
10 and 12%).
The transformation described in Eq. (15) indicates
that the low diastereoselectivity observed during the
formation of 42 is lost during the transfer of the
alkylidene group: this means that either the transfer
occurred via the planar alkylidene complex, or that one
of the two diastereoisomers reacts (or decomposes)
faster then the other one. For the transformations
depicted in the Eqs. 16 and 17, the overall diastereose-
lectivity would thus be assignable to the presence of a
chiral center in the starting carbene complexes. Further
experiments are in progress in order to clarify these
points.
(14)
The low diastereoselectivities observed for the reduc-
tions of the different carbene complexes might be in-
ferred on the one hand from the mechanism of the
reduction, since a planar alkylidene complex is proba-
bly an intermediate (Eq. (6)), and on the other hand to
the distance of the chiral center from the carbene
carbon.
Both chiral nicotinium ylid complexes 42 and 44
could be fully characterized by their physical data (see
Section 4).
(15)
(16)
2.2.3. Transfer of the chiral alkylidene groups
It is known that alkylidene groups originating from
pyridinium ylides can be transferred to electrophilic
olefines to give either cyclopropanes or car-
bonꢀhydrogen insertion products [33,34]. We have
demonstrated that pyridinium ylid complexes are ver-

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Similarly, N-methyldihydropyridine 56 led under the
same conditions to the metal-free bicyclic amine 57.
However, the interaction of 1,4-dihydropyridine 58 did
not lead to the related cyclopropanated compound 59.
It appears therefore that the 1,2-dihydropyridines
react like enamines, the more reactive double bond
being selectively cyclopropanated: this confirms that the
less stable among the five dihydropyridines [36], the
1,2-dihydropyridine, is also the more nucleophilic.
(17)
2.3. Cyclopropanation of dihydropyridines and indoles
2.3.1. Dihydropyridines
We have already demonstrated the high reactivity of
enamines towards the pyridinium ylid complexes [35].
Two further examples are related to the cyclopropana-
tion of special types of enamines: dihydropyridines and
indoles.
2.3.2. Indoles
Indoles can be expanded to quinolines upon treat-
ment with carbenes [37]. We first examined the case of
N-methyl indole 60: it reacts with complex 27 at room
temperature to give after silica gel chromatography, a
53% yield of the expected cyclopropanated compound
61 as a single exo isomer (Eq. (21)).
During the preparation of the pyridinium complex 27
from complex 50 and a mixture of 1,2 and 1,4-dihy-
dropyridines, a new yellow polar complex was unex-
1
pectedly isolated in 8% yield: according to its H-NMR
spectrum, it contained both a phenyl-substituted cyclo-
propane and a disubstituted double bond. The mass
spectrum was in agreement with structure 51, a pen-
tacarbonyl tungsten complex of the cyclopropanated
1,2-dihydropyridine (Eq. (18)).
(21)
When the same reaction was carried out on indole
62, then again a fast disappearance of the starting
complex took place. However, it appeared that the
expected cyclopropane 63 which could indeed be de-
tected by NMR in the crude reaction mixture, was
unstable on silica gel. Therefore, the mixture was
treated in refluxing benzene with palladium on char-
coal: this led to the formation of the ring-expanded
indole, the quinoline 64 in a 56% overall yield (Eq.
(22)).
(18)
A similar observation was made during the reduction
of complex 52 which led to complex 54 in 2% yield (Eq.
(19)).
(19)
In order to confirm this possibility, a stoichiometric
amount of the ylide complex 27 was added to the pure
1,2-dihydropyridine 55 at room temperature. And in-
deed, the same complex 51 was isolated in a 24% yield
(Eq. (20)).
(22)
These two transformations confirmed again the high
reactivity of these complexes towards the most nucleo-
philic carbonꢀcarbon double bonds.
2.3.3. Bis(trimethylsilyl) ketene acetals
Among the substrates which gave the best yields of
cyclopropanes when subjected to the reaction with a
series of pyridinium ylid complexes, the highly nucleo-
philic bis(trimethylsilyl) ketene acetals appeared as the
most efficient [22]. In all the cases examined, high yields
of cyclopropanes were indeed obtained as mixtures of
isomers. In order to try to increase the stereoselectivity
(20)

H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
577
of the transfer or to carry out enantioselective reactions,
we used the bulky menthoxy group in the starting ketene
acetal. The related ketene acetal 67 was easily prepared
from the commercially available menthoxyacetic acid 65
in two steps via 66 and was subjected to the reaction with
27 (Eq. (23)).
(24)
(23)
2.4. Synthesis of the ‘queen substance’
A very fast reaction was observed even at room
temperature: after 5 min all the complex had disappeared.
Surprisingly, almost no signals due to the expected
cyclopropanes 68 could be detected in the NMR spectrum
of the reaction mixture: instead, signals at low field due
to conjugated trimethylsilylcarboxylates 69 were ob-
served.
Attempts to separate the reaction products by silica gel
chromatography led exclusively to a 63:37 mixture of E:Z
cinnamic acid 70 in 90% yield (Eq. (24)). Thus, complete
loss of the menthoxy group was observed. Similar
reactions were then carried out on a series of simpler
alkoxy-substituted ketene acetals and various pyridinium
ylid complexes. As can be seen in Table 1, high to
moderate yields of the expected conjugated acids were
obtained in most of the cases by simple treatment of the
reaction mixture with a base followed by reacidification
and extraction with diethyl ether. It is thus likely that this
special type of ketene acetals reacts in the same way as
the alkyl or aryl-substituted acetals with the pyridinium
ylid complexes to give intermediate, unstable, isomeric
cyclopropanes. Once formed, the cyclopropanes undergo
an elimination of the alkoxy group with ring-opening,
each isomer leading probably selectively to a single olefin.
Since functionalized pyridinium ylid complexes are
easily prepared, we undertook the synthesis of the more
elaborate 9-oxo-dec-2-enoic acid, known as the honey bee
queen substance [38,39].
Numerous syntheses of the queen substance have been
described in the literature [40]. However, none of them
uses carbene complexes.
According to the retrosynthetic picture (Eq. (25)), the
carbene complex which has to be synthesized is 74: thus
7-bromoheptan-2-one 72 is required in a protected form
for the preparation of the precursor of the carbene
complex, the corresponding organolithium derivative.
(25)
Table 1

578
H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
Access to this compound is straightforward from the
atmosphere. Solvents were distilled from sodium/ben-
zophenone ketyl (diethyl ether, tetrahydrofurane), phos-
phorus pentoxide (dichloromethane) and saturated with
argon. Silica gel (E. Merck, type 60, 0.063–0.200 mm)
was used for column chromatography. 1H-NMR: Bruker
ARX-400 (400 MHz). 13C-NMR: Bruker ARX-400 (100
MHz). All NMR spectra were recorded in CDCl3 with
CHCl3 as internal standard. MS and HRMS: Jeol MS
700. m.p.: Reichert, the reported melting points are
uncorrected. TLC: 0.25 mm E. Merck silica gel plates 60
F254. UV spectrometer: HP 8452A. Measurements in 5
mm quartz cells in CH2Cl2. [h]D measurements in CHCl3,
[c]=0.01 g/ml.
commercially available 6-bromohexanoic acid 71: treat-
ment with MeLi leads to the methyl ketone 72 (Eq. (26)).
Two possibilities existed at this point for the formation
of the required lithium derivative: the transformation of
the bromide 72 into the protected iodide 73 or a direct
treatment of the protected bromide with tBuli.
4.2. Preparation of the carbene complexes 17, 23, 35,
37, 40, 43, 50 and 52
(26)
Carbene complexes 40 and 50 were prepared following
the literature procedure [41].
The expected carbene complex 74 was obtained in 46%
yield (no optimization). Its reaction with a mixture of
dihydropyridines, obtained upon reduction of pyridine
with LiAlH4, gave an 82% yield of the expected ylid
complex 75. Interaction of this ylid complex with the
ketene acetal 67 led, upon work up as above, to a 66%
yield of a 80:20 mixture of E, Z isomers, which are both
active [39] of the expected acid 76 after deprotection and
work up (Eq. (27)).
Carbene complexes 17, 35, 37, 43 and 52 were prepared
by a halogen–metal exchange reaction.
Typical procedure: to a solution of bromocyclopropane
(0.68 ml, 8.5 mmol) in Et2O (20 ml) at −78°C, was added
slowly a solution of t-BuLi (10 ml, 1.7 M) in hexane. After
30 min at −78°C, the reaction medium was transferred
to a flask containing a suspension of W(CO)6 (3.0 g, 8.5
mmol) in Et2O (30 ml) at 0°C. After 1 h at room
temperature, the mixture turned brown. The solvent was
evaporated in vacuo. The crude was dissolved in water
(60 ml) and petroleum ether (PE) (30 ml). Et3O+BF4− (1.6
g, 8.5 mmol) was then added in small portions and the
organic layer turned instantaneously from colorless to
orange.
The mixture was extracted with PE. After washing
(saturated aqueous NaHCO3 solution, water and brine)
and drying (Na2SO4), the solvent was evaporated in vacuo
and the residue purified by silica gel chromatography (PE)
to afford the complex 17 (1.38 g, 3.3 mmol) as light yellow
crystals in 39% yield.
(27)
Pentacarbonyl (ethoxy cyclopropyl carbene) tungsten 17
(light yellow solid, 39% yield, m.p. 34°C): 1H-NMR
(CDCl3, 400 MHz) l 4.79 (q, J=7.0 Hz, 2H, OCH2), 3.46
(m, 1H, CH), 1.50 (t, J=7.0 Hz, 3H, CH3), 1.38, 1.20
(m, 4H, CH2); 13C-NMR (CDCl3, 100 MHz) l 326.1
(WꢁC), 203.9 (CO trans), 197.8 (CO cis), 79.3 (OCH2),
44.2 (CH), 17.8 (CH3, CH2), 14.6 (CH2). Anal. Calc. for
C11H10O6W: C, 31.30; H, 2.39. Found: C, 31.44; H, 2.22%.
The carbene complexes 52, 43, 35 and 37 were prepared
using the same procedure.
Pentacarbonyl(ethoxy3-phenylpropylcarbene)tungsten
52 (orange oil, 85% yield): umax=369 nm. 1H-NMR
(CDCl3, 400 MHz) l 7.36–7.16 (m, 5H, Ph), 4.90 (q,
J=7.2 Hz, 2H, OCH2), 3.26 (t, J=7.4 Hz, 2H, ꢁCꢀCH2),
2.65 (t, J=7.8 Hz, 2H, CH2Ph), 1.92–1.79 (m, 2H, CH2),
0.61 (t, J=7.2 Hz, 3H, CH3); 13C-NMR (CDCl3, 100
MHz) l 333.4 (WꢁC), 203.6 (CO trans), 197.4 (CO cis),
141.5, 128.5, 128.4, 126.2 (Ph), 80.7 (OCH2), 64.7
3. Conclusion
New applications of the pyridinium ylid complexes of
tungsten prepared from alkoxycarbene complexes of
tungsten both in racemic and optically active forms, have
been described. The more promising aspects of this new
chemistry are related to the transfer of elaborate, chiral
and highly functionalized alkylidene groups to car-
bonꢀcarbon double bonds. Work is progressing towards
these goals.
4. Experimental
4.1. General
All reactions were performed under a dry argon

H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
579
(ꢁCꢀCH2), 35.4 (CH2Ph), 28.1 (CH2), 14.8 (CH3).
4.3. Preparation of the dihydropyridines 13
HRMS Calc. for C17H16O6W (M+) 500.0456. Found:
500.0457%.
In a flask equipped with a condenser, pyridine (6
ml) was treated with a solution of LiAlH4 (4.5 mmol,
1 M) in THF. The yellow solution was heated at
70°C for 5 h and then cooled in an ice-bath. Satu-
rated aqueous sodium and potassium tartrate solution
(10 ml) was then added slowly. The mixture was ex-
tracted with Et2O. After washing (water and brine)
and drying (Na2SO4), the ethereal phase containing
the dihydropyridines 13 (12 mmol) was immediately
added to the carbene complexes without further
purification.
Pentacarbonyl (ethoxy 2-cyclopentylethyl carbene)
tungsten 43 (light yellow solid, 60% yield, m.p. 31°C):
1H-NMR (CDCl3, 400 MHz) l 4.89 (q, J=7.0 Hz,
2H, OCH2), 3.24 (d, J=5.0 Hz, 2H, ꢁCꢀCH2), 2.24
(hept, J=5.0 Hz, 1H, CH), 1.83–1.44, 1.21–1.04 (m,
8H, CH2), 1.61 (t, J=7.0 Hz, 3H, CH3); 13C-NMR
(CDCl3, 100 MHz) l 334.6 (WꢁC), 202.9 (CO trans),
197.5 (CO cis), 80.7 (OCH2), 71.1 (ꢁCꢀCH2), 38.0
(CH), 32.5, 24.8 (CH2), 14.9 (CH3). Anal. Calc. for
C14H16O6W: C, 36.20; H, 3.47. Found: C, 36.17; H,
3.65%.
The same procedure was used to prepare the mix-
ture of chiral dihydronicotines 41.
Pentacarbonyl (ethoxy 2-(S)-methylbutyl carbene)
tungsten 35 (orange oil, 38% yield, [h]D= +11.9°):
1H-NMR (CDCl3, 400 MHz) l 4.93 (q, J=6.8 Hz,
2H, OCH2), 3.16 (dd, J=14.4 Hz, J%=6.0 Hz, 1H,
ꢁCꢀCHH%), 3.09 (dd, J=14.4 Hz, J%=8.0 Hz, 1H,
ꢁCꢀCHH%), 2.05 (oct, J=6.8 Hz, 1H, CH), 1.65 (t,
J=6.8 Hz, 3H, OꢀCꢀCH3), 1.34–1.19 (m, 2H, CH2),
0.89 (t, J=7.6 Hz, 3H, CH2ꢀCH3), 0.88 (d, J=7.6
Hz, 3H, CH3); 13C-NMR (CDCl3, 100 MHz) l 336.1
(WꢁC), 203.5 (CO trans), 197.5 (CO cis), 80.7
(OCH2), 72.0 (ꢁCꢀC), 33.9 (CH), 29.8 (CH2), 19.4
(CHꢀCH3), 14.8 (OꢀCꢀCH3), 11.6 (CH3). HRMS
Calc. for C13H16O6W (M+) 452.0459. Found:
452.0456.
4.4. Preparation of the pyridinium ylid complexes 18,
26, 27, 32, 36, 38, 45 and 53
Typical procedure: to a solution of carbene com-
plex 40 (2.38 g, 6.0 mmol) in Et2O (40 ml) was added
a freshly prepared ethereal solution of the dihydropy-
ridines 13. The solution turned instantaneously from
orange to red and, after 5 min, the solvent was evap-
orated in vacuo. The crude mixture was chro-
matographed on silica gel (40% CH2Cl2/PE) to give
the pyridinium ylid complex 45 (2.43 g, 5.6 mmol,
94%) as an orange solid.
Pyridinium ylid complex 45 (orange solid, 94%
1
yield, m.p. 127°C): umax=334 nm. H-NMR (CDCl3,
400 MHz) l 8.55 (d, J=6.0 Hz, 2H, Ho py.), 7.82
(m, 1H, Hp py.), 7.59 (m, 2H, Hm py.), 4.90 (q, J=
7.0 Hz, 1H, CH), 2.53 (d, J=7.0 Hz, 3H, CH3);
13C-NMR (CDCl3, 100 MHz) l 204.5 (CO trans),
201.9 (CO cis), 139.2, 136.2, 126.6 (py.), 57.2 (CH),
30.7 (CH3). Anal. Calc. for C12H19NO5W: C, 33.42;
H, 2.08; N, 3.25. Found: C, 33.49; H, 2.17; N, 3.35.
The other pyridinium ylid complexes were prepared
using the same procedure.
Pyridinium ylid complex 27 (brown solid, 88% yield,
m.p. 105°C); umax=341 nm. 1H-NMR (CDCl3, 400
MHz) l 8.92 (d, J=6.0 Hz, 2H, Ho py.), 7.90 (m,
1H, Hp py.), 7.66 (m, 2H, Hm py.), 7.39–7.25 (m, 5H,
Ph), 6.03 (s, 1H, CH); 13C-NMR (CDCl3, 100 MHz)
l 203.9 (CO trans), 201.6 (CO cis), 148.7, 141.9,
138.4 (py.), 128.7, 127.6, 126.7, 125.7 (Ph) 70.8 (CH).
Anal. Calc. for C17H11NO5W: C, 44.38; H, 2.23; N,
2.84. Found: C, 44.27; H, 2.34; N, 2.71.
Pyridinium ylid complex 18 (orange solid, 48% yield
(using Fowler’ method) [32], m.p. 83°C): umax=338
nm. 1H-NMR (CDCl3, 400 MHz) l 8.59 (d, J=7.2
Hz, 2H, Ho py.), 7.84 (t, J=7.2 Hz, 1H, Hp py.),
7.60 (t, J=7.2 Hz, 2H, Hm py.), 3.91 (d, J=10.6 Hz,
1H, WꢀCH), 2.01 (m, 1H, CH), 1.03, 0.69, 0.53, 0.10
(m, 4H, CH2); 13C-NMR (CDCl3, 100 MHz) l 204.7
(CO trans), 201.9 (CO cis), 139.5, 136.5, 126.5 (py.),
70.4 (WꢀC), 24.9 (CH), 10.4, 10.2 (CH2). Anal. Calc.
Pentacarbonyl (ethoxy 3(S),7-dimethyl oct-6-enyl
carbene) tungsten 37 (yellow oil, 50% yield, [h]D= +
8.6°): H-NMR (CDCl3, 400 MHz) l 5.11 (t, J=7.2
1
Hz, 1H, H7), 4.89 (q, J=7.2 Hz, 2H, OCH2), 3.21
(m, 2H, H2), 1.99 (m, 2H, H6), 1.71 (s, 3H, ꢁCꢀCH3),
1.64 (s, 3H, ꢁCꢀCH3), 1.62 (t, J=7.2 Hz, 3H,
OꢀCꢀCH3), 1.56–1.13 (m, 5H, H3, H4, H5), 0.92 (d,
J=6.4 Hz, 3H, CHꢀCH3); 13C-NMR (CDCl3, 100
MHz) l 334.7 (WꢁC), 203.4 (CO trans), 197.4 (CO
cis), 131.5 (C8), 124.6 (C7), 80.7 (OCH2), 62.9 (C2),
36.9 (C6), 33.3 (C3), 32.4 (ꢁCꢀCH3), 29.2 (CH), 25.8
(ꢁCꢀCH3), 25.5 (C5), 19.5 (CHꢀCH3), 14.8
(OꢀCꢀCH3). HRMS Calc. for C18H25O6W (MH+)
520.1157. Found: 520.1161.
The carbene complex 23 was prepared using a
known procedure [26] starting from complex 40.
Pentacarbonyl (ethoxy cyclopropyl carbene) tungsten
1
23 (yellow solid, 41% yield, m.p. 61–62°C): H-NMR
(CDCl3, 400 MHz) l 4.90 (t, J=8.0 Hz, 2H, OCH2),
3.45 (t, J=8.0 Hz, 2H, ꢁCꢀCH2), 1.95 (quint, J=8.0
Hz, 2H, CH2); 13C-NMR (CDCl3, 100 MHz) l 314.4
(WꢁC), 203.1 (CO trans), 197.0 (CO cis), 85.6
(OCH2), 63.2 (ꢁCꢀCH2), 20.8 (CH2).

580
H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
for C14H11NO5W: C, 36.79; H, 2.43; N, 3.06. Found: C,
36.87; H, 2.52; N, 2.91.
Pyridinium ylid complex 38 (orange solid, 90% yield,
m.p. 44°C, two isomers ‘A (major) and B (minor)’:
de=10%): 1H-NMR (CDCl3, 400 MHz) (isomers A
and B are not separated by 1H-NMR) l 8.53 (d, J=6.2
Hz, 2H, Ho py.), 7.85 (t, J=6.2 Hz, 1H, Hp py.), 7.62
(t, J=6.2 Hz, 2H, Hm py.), 5.08 (m, 1H, H7), 4.65 (m,
1H, H1), 2.67 (m, 2H, H6), 1.92 (m, 2H, H2), 1.70 (s,
3H, ꢁCꢀCH3), 1.60 (s, 3H, ꢁCꢀCH3), 1.47–1.13 (m, 5H,
H3, H4, H5), 0.88 (d, J=6.4 Hz, CHꢀCH3); 13C-NMR
(CDCl3, 100 MHz) l 204.6 (CO trans (A and B)), 202.0
(CO cis (A and B)), 136.6 (CHo py. (A and B)), 130.9
(C8 (A and B)), 126.8 (CHm, CHp py. (A and B)), 124.7
(C7 (A and B)), 65.1 (C1 (A)), 64.7 (C1 (B)), 41.7 (C6
(A)), 41.5 (C6 (B)), 37.3 (C2 (A)), 37.1 (C2 (B)), 36.9 (C5
(A)), 36.7 (C5 (B)), 32.2 (ꢁCꢀCH3 (A)), 32.0 (ꢁCꢀCH3
(B)), 30.9 (CHꢀCH3 (A and B)), 25.8 (ꢁCꢀCH3 (A and
B)), 25.5 (CH2 (A and B)), 19.7(CHꢀCH3 (A)), 32.0
(CHꢀCH3 (B)). HRMS Calc. for C21H25NO5W (M+)
555.1246. Found: 555.1242.
Pyridinium ylid complex 26 (yellow solid, 66% yield,
m.p. 79°C): 1H-NMR (CDCl3, 400 MHz) l 8.51 (d,
J=6.8 Hz, 2H, Ho py.), 7.84 (t, J=6.8 Hz, 1H, Hp
py.), 7.60 (t, J=6.8 Hz, 2H, Hm py.), 4.65 (dd, J=10.0
Hz, J%=5.8 Hz, 1H, WꢀCH), 3.65 (t, J=6.4 Hz, 2H,
OCH2), 2.81–2.42 (m, 2H, WꢀCꢀCH2), 2.07 (broad s,
1H, OH), 1.47 (m, 2H, CH2); 13C-NMR (CDCl3, 100
MHz) l 204.7 (CO trans), 201.9 (CO cis), 140.1, 137.0,
127.0 (py.), 63.9 (WꢀC), 62.2 (OCH2), 40.5
(WꢀCꢀCH2), 32.5 (CH2). HRMS Calc. for
C14H13NO6W (M+) 475.0255. Found: 475.0252.
Pyridinium ylid complex 53 (orange solid, 49% yield
(using Fowler’s method) [32], m.p. 128°C): umax=344
1
nm. H-NMR (CDCl3, 400 MHz) l 8.39 (d, J=6.0 Hz,
2H, Ho py.), 7.80 (m, 1H, Hp py.), 7.54 (m, 2H, Hm
py.), 7.31–7.17 (m, 5H, Ph), 4.65 (dd, J=10.0 Hz,
J%=6.0 Hz, 1H, WꢀCꢀH), 2.72–2.52 (m, 4H,
WꢀCꢀCH2, CH2Ph), 1.53 (m, 2H, CH2); 13C-NMR
(CDCl3, 100 MHz) l 204.4 (CO trans), 202.0 (CO cis),
139.9, 136.5, 126.8 (py.), 142.1, 128.5, 128.4, 126.0 (Ph),
64.1 (WꢀC), 43.6 (CH2Ph), 35.5 (WꢀCꢀCH2), 31.5
(CH2). Anal. Calc. for C20H17NO5W: C, 44.87; H, 3.18;
N, 2.62. Found: C, 44.98; H, 3.23; N, 2.55.
Pyridinium ylid complex 32 (orange solid, 82% yield,
1
m.p. 113°C): H-NMR (CDCl3, 400 MHz) l 8.52 (d,
J=6.0 Hz, 2H, Ho py.), 7.82 (m, 1H, Hp py.), 7.58 (m,
2H, Hm py.), 4.76 (dd, J=10.6 Hz, J%=5.0 Hz, 1H,
WꢀCH), 2.74 (m, 1H, WꢀCꢀCHH%), 2.30 (m, 1H,
WꢀCꢀCHH%), 1.64ꢀ1.41 (m, 7H, CH, CH2), 1.19–1.12
(m, 2H, CH2); 13C-NMR (CDCl3, 100 MHz) l 204.8
(CO trans), 202.0 (CO cis), 140.1, 136.5, 126.8 (py.),
63.1 (WꢀC), 50.5 (WꢀCꢀCH2), 39.1, 32.8, 31.8, 25.2,
25.1 (CH, CH2). Anal. Calc. for C17H17NO5W: C,
40.88; H, 3.44; N, 2.81. Found: C, 40.81; H, 3.63; N,
2.97.
Pyridinium ylid complex 36 (orange solid, 78% yield,
m.p. 74°C, two isomers ‘A (major) and B (minor)’:
1
de=6%): H-NMR (CDCl3, 400 MHz) l 8.52 (d, J=
6.8 Hz, 4H, Ho py. (A and B)), 7.85 (t, J=6.8 Hz, 2H,
Hp py. (A and B)), 7.61 (t, J=6.8 Hz, 4H, Hm py. (A
and B)), 4.91 (dd, J=11.7 Hz, J%=4.6 Hz, 1H,
WꢀCꢀH (A)), 4.85 (dd, J=10.1 Hz, J%=5.6 Hz, 1H,
WꢀCꢀH (B)), 2.78 (ddd, J=15.6 Hz, J%=11.6 Hz,
J%%=3.6 Hz, 1H, WꢀCꢀCHH% (A)), 2.53 (ddd, J=15.2
Hz, J%=10.0 Hz, J%%=4.8 Hz, 1H, WꢀCꢀCHH% (B)),
2.38 (ddd, J=15.2 Hz, J%=8.0 Hz, J%%=5.6 Hz, 1H,
WꢀCꢀCHH% (B)), 2.10 (ddd, J=15.6 Hz, J%=9.6 Hz,
J%%=4.8 Hz, 1H WꢀCꢀCHH% (A)), 1.52–1.42 (m, 1H,
CH (A)), 1.40–1.26 (m, 3H, CH (B), CH2 (A)), 1.21–
1.05 (m, 2H, CH2 (B)), 0.87–0.80 (m, 12H, CH3 (A and
B)); 13C-NMR (CDCl3, 100 MHz) l 204.5 (CO trans (A
and B)), 202.0 (CO cis (A and B)), 136.4 (CHo, CHp py.
(A and B)), 126.7 (CHm py. (A and B)), 61.6 (WꢀC
(A)), 60.8 (WꢀC (B)), 51.0 (WꢀCꢀCH2 (A)), 50.6
(WꢀCꢀCH2 (B)), 32.9 (CH (A and B)), 29.9 (CH2 (A)),
28.1 (CH2 (B)), 19.6 (CHꢀCH3 (B)), 18.4 (CHꢀCH3
(A)) 11.5 (CH2ꢀCH3 (A)), 10.8 (CH2ꢀCH3 (B)). HRMS
Calc. for C16H17NO5W (M+) 487.0619. Found:
487.0616.
The same procedure was used to prepare the nico-
tinium ylid complexes 42 and 44 from a solution of
chiral dihydronicotines 41 and the corresponding car-
bene complexes 40 and 43.
Nicotinium ylid complex 42 (orange oil, 72% yield,
two isomers ‘A (major) and B (minor)’: de=10%):
1H-NMR (CDCl3, 400 MHz) l 8.61 (s, 2H, H3 (A and
B)), 8.45 (d, J=6.0 Hz, 2H, H7 (A and B)), 7.84 (d,
J=7.8 Hz, 2H, H5 (A and B)), 7.52 (dd, J=7.8 Hz,
J%=6.0 Hz, 2H, H6 (A and B)), 4.88 (q, J=7.2 Hz,
1H, H1 (A)), 4.87 (q, J=7.2 Hz, 1H, H1 (B)), 3.34 (m,
4H, H11 (A and B)), 2.39 (q, J=8.9 Hz, 2H, H10 (A
and B)), 2.32 (d, J=7.2 Hz, 6H, H2 (A and B)), 2.28
(m, 2H, H10% (A and B)), 2.25 (s, 6H, H12 (A and B)),
1.97 (m, 2H, H8 (A and B)), 1.87 (m, 2H, H9 (A and
B)), 1.69 (m, 2H, H9% (A and B)); 13C-NMR (CDCl3,
100 MHz) l 205.0 (CO trans (A and B)), 202.5 (CO cis
(A and B)), 138.9 (C3 (A and B)), 138.0 (C4 (A)), 137.9
(C4 (B)), 135.8 (C7 (A and B)), 132.4 (C5 (A and B)),
126.7 (C6 (A and B)), 68.4 (C11 (A and B)), 57.2 (C1 (A

H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
581
and B)), 40.7 (C12 (A and B)), 35.8 (C10 (A and B)), 31.2
(C2 (A)), 31.1 (C2 (B)), 23.3 (C9 (A and B)). HRMS Calc.
for C17H18N2O5W (M+) 514.0725. Found: 514.0728.
4H,OCH2), 2.61 (dt, J=12.0 Hz, J%=4.8 Hz, 2H,
NꢀCHH%), 2.51 (dt, J=12.0 Hz, J%=4.8 Hz, 2H,
NꢀCHH%), 2.00 (m, 1H, H5), 1.90 (m, 1H, H3), 1.79 (m,
1H, H4), 1.65 (m, 2H, H3%, H5%), 1.48 (m, 1H, H4%), 1.26
(dd, J=9.2 Hz, J%=5.6 Hz, 1H, H2), 0.60 (t, J=9.2 Hz,
1H, H6), 0.57 (m, 2H, H8, H9), 0.38 (m, 1H, H7), 0.19
(m, 2H, H8%, H9%); 13C-NMR (100 MHz, CDCl3) l 67.3
(OCH2), 58.5 (C1), 49.8 (NCH2), 34.7 (C6), 28.8 (C2), 25.0
(C4), 24.7 (C3), 20.7 (C5), 5.8, 5.7 (C8, C9), 5.3 (C7).
HRMS Calc. for C13H21NO (M+) 207.1623. Found:
207.1622.
To a solution of 4-cyclopent-1-enyl morpholine (393
ml, 2.5 mmol) in CH2Cl2 (15 ml) was added the pyri-
dinium ylid complex 36 (300 mg, 0.62 mmol). The
solution was stirred for 12 h at reflux then the solvent
was evaporated in vacuo. After chromatography, the
cyclopropane 48 exo (5% Et2O/PE, 88 mg, 0.37 mmol)
was obtained as a colourless oil in 60% yield.
Nicotinium ylid complex 44 (orange oil, 47% yield, two
isomers ‘A (major) and B (minor)’: de=10%): 1H-NMR
(400 MHz, CDCl3) l 8.53 (d, J=6.8 Hz, 1H, H8), 8.36
(dd, J=7.2 Hz, J=6.8 Hz, 1H, H12), 7.76 (d, J=7.2 Hz,
1H, H10), 7.49 (m, 1H, H11), 4.74 (dd,
J=10.6 Hz, J=5.2 Hz, 1H, H1), 3.26 (m, 2H, H6), 2.73
(m, 1H, H2), 2.45–2.20 (m, 2H, H2%, H15), 2.21 (s, 3H,
H17), 1.98–1.79 (m, 2H, H13, H15’), 1.72–1.51 (m, 7H, H3,
H4, H7, H14), 1.49–1.37 (m, 2H, H5, H6), 1.21–1.08 (m,
2H, H5%, H6%); 13C-NMR (100 MHz, CDCl3) l 204.7 (CO
trans), 202.1 (CO cis), 144.9 (C9), 139.3 (C8), 138.4 (C12),
135.8 (C10), 126.3 (C11), 67.9 (C16), 62.6 (C1), 56.8 (C13),
50.5 (C2 (A)), 50.4 (C2 (B)), 40.4 (C17), 39.3 (C3), 35.6
(C15), 32.8 (C4), 31.9 (C7), 25.3 (C5), 25.1 (C6), 23.0 (C14).
HRMS Calc. for C22H26N2O5W (M+) 582.1351. Found:
582.1355.
Cyclopropane 48 exo (colourless oil, 60% yield, two
isomers ‘A (major) and B (minor)’: de=20%): 1H-NMR
(400 MHz, CDCl3), the two isomers were not separated
4.5. Cyclopropanation reactions of pyridinium and
nicotinium ylid complexes with enamines
1
by H-NMR l 3.57 (t, J=4.4 Hz, 4H, OCH2), 2.59 (m,
2H, NꢀCHH%), 2.43 (m, 2H, NꢀCHH%), 1.81 (dt, J=11.7
Hz, J%=8.6 Hz, 1H, H2), 1.64–1.44 (m, 4H, H3, H4, H4%,
H5), 1.36–1.23 (m, 4H, H7, H7%, H8, H9), 1.13–1.03 (m,
2H, H3%, H9%), 0.83 (d, J=7.2 Hz, 3H, H11), 0.80 (t,
J=7.6 Hz, 3H, H10), 0.73 (m, 1H, H5%), 0.65 (m, 1H, H6);
13C-NMR (100 MHz, CDCl3) l 66.5 (OCH2 (A and B)),
55.5 (C1 (A)), 55.2 (C1 (B)), 49.2 (NCH2 (A and B)), 34.5
(C8 (B)), 34.2 (C8 (A)), 32.5 (C7 (B)), 32.3 (C7 (A)), 29.3
(C5 (B)), 29.0 (C5 (A)), 28.7 (C9 (B)), 28.6 (C9 (A)), 26.1
(C4 (A)), 26.0 (C4 (B)), 24.0 (C6 (B)), 23.8 (C6 (A)), 22.0
(C2 (B)), 21.9 (C2 (A)), 21.0 (C3 (A and B)), 18.6 (C11 (B)),
18.5 (C11 (A)), 10.6 (C7 (A and B)). HRMS Calc. for
C15H27ON (M+) 237.2093. Found: 237.2092.
To a solution of 4-cyclopent-1-enyl morpholine [42]
(350 ml, 2.2 mmol) in CH2Cl2 (10 ml) was added the
pyridinium ylid complex 18 (0.25 g, 0.55 mmol). The
solution was stirred for 3 h at room temperature then the
solvent was evaporated in vacuo. After chromatography,
19 exo (PE, 66 mg, 0.32 mmol) and 19 endo (5% Et2O/PE,
48 mg, 0.23 mmol) were obtained as colourless oils in
quantitative yield.
To a solution of 4-cyclopent-1-enyl morpholine (480
ml, 3.0 mmol) in CH2Cl2 (15 ml) was added the pyri-
dinium ylid complex 38 (555 mg, 1.0 mmol). The solution
was stirred for 5 h at reflux then the solvent was
evaporated in vacuo. After chromatography, the cyclo-
propane 49 exo (2% Et2O/PE, 146 mg, 0.47 mmol) and
49 endo (15% Et2O/PE, 96 mg, 0.32 mmol) were obtained
as colourless oils in 79% yield.
1
Cyclopropane 19 exo (colourless oil, 58% yield): H-
NMR (400 MHz, CDCl3) l 3.63 (t, J=5.2 Hz, 4H,
OCH2), 2.78 (dt, J=11.2 Hz, J%=5.2 Hz, 2H,
NꢀCHH%), 2.52 (dt, J=11.2 Hz, J%=5.2 Hz, 2H,
NꢀCHH%), 1.86 (m, 1H, H5), 1.68 (m, 1H, H3), 1.56 (m,
3H, H3%, H4, H5%), 1.06 (m, 1H, H4%), 0.97 (t, J=4.0 Hz,
1H, H2), 0.81 (m, 1H, H7), 0.42 (m, 2H, H8, H9), 0.20
(dd, J=8.6 Hz, J=4.0 Hz, 1H, H6), 0.15, 0.07 (m, 2H,
H8%, H9%); 13C-NMR (100 MHz, CDCl3) l 67.6 (OCH2),
56.7 (C1), 50.1 (NCH2), 31.0 (C6), 29.3 (C2), 27.0 (C3),
22.7 (C5), 21.7 (C4), 8.4 (C7), 5.2, 3.9 (C8, C9).
Cyclopropane 19 endo (colourless oil, 42% yield):
1H-NMR (400 MHz, CDCl3) l 3.6 (t, J=4.8 Hz,

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H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
Cyclopropane 49 exo (colorless oil, 47% yield, two
NꢀCHH%), 1.86 (m, 1H, H5), 1.67 (m, 1H, H4), 1.64–
1.59 (m, 2H, H3), 1.51 (m, 1H, H5%), 1.14 (m, 1H, H4%),
1.07 (d, J=6.0 Hz, 3H, CH3), 0.76 (m, 1H, H6), 0.73
(m, 1H, H2); 13C-NMR (100 MHz, CDCl3) l 67.6
(OCH2), 56.1 (C1), 50.2 (NCH2), 30.8 (C2), 27.0 (C3),
22.8 (C5), 22.0 (C4), 20.3 (C6), 11.6 (CH3). MS Calc. for
C11H19ON (M+−Me) 166. Found: 166.
isomers ‘A (major) and B (minor)’: de=12%): 1H-
NMR (400 MHz, CDCl3), the two isomers were not
1
separated by H-NMR l 5.04 (t, J=7.2 Hz, 1H, H12),
3.57 (t, J=4.0 Hz, 4H, OCH2), 2.60 (m, 2H, NꢀCHH%),
2.44 (m, 2H, NꢀCHH%), 1.90 (m, 2H, H11), 1.80 (dt,
J=11.2 Hz, J%=8.0 Hz, 1H, H2), 1.62 (s, 3H, H14),
1.58–1.43 (m, 5H, H2%, H3, H4, H4%, H7), 1.54 (s, 3H,
H14%), 1.37–1.18 (m, 4H, H7%, H8, H9, H10), 1.16–1.03
(m, 3H, H3%, H8%,H10%), 0.79 (d, J=6.4 Hz, 3H, H15),
0.70 (t, J=4.0 Hz, 1H, H5), 0.60 (m, 1H, H6); 13C-
NMR (100 MHz, CDCl3) l 132.5 (C13 (A and B)),
124.0 (C12 (A and B)), 66.5 (OCH2 (A and B)), 56.9 (C1
(A and B)), 49.2 (NCH2 (A and B)), 36.6 (C8 (B)), 36.3
(C8 (A)), 36.2 (C10 (B)), 36.1 (C10 (A)), 31.5 (C9 (B)),
31.4 (C9 (A)), 28.6 (C5 (B)), 28.5 (C5 (A)), 26.1 (C4 (A
and B)), 26.0 (C6 (B)), 25.9 (C6 (A)), 24.7 (C14 (A and
B)), 24.5 (C11 (A and B)), 23.0 (C7 (A)), 22.8 (C7 (B)),
22.0 (C2 (A and B)), 20.9 (C3 (A and B)), 18.7 (C14% (A
and B)), 16.6 (C15 (A and B)). HRMS Calc. for
C20H35ON (MH+) 306.2797. Found: 306.2797.
1
Cyclopropane 47 endo (colorless oil, 18% yield): H-
NMR (400 MHz, CDCl3) l 3.63 (t, J=4.6 Hz, 4H,
OCH2), 2.65 (dt, J=11.2 Hz, J%=4.6 Hz, 2H,
NꢀCHH%), 2.51 (dt, J=11.2 Hz, J%=4.6 Hz, 2H,
NꢀCHH%), 2.04 (m, 1H, H3), 1.90 (m, 1H, H5), 1.75 (m,
1H, H4), 1.70 (m, 1H, H3%), 1.45 (m, 1H, H6), 1.42 (m,
1H, H5%), 1.32 (m, 1H, H4’), 1.25 (m, 1H, H2), 0.93 (d,
J=6.8 Hz, 3H, CH3); 13C-NMR (100 MHz, CDCl3) l
67.4 (OCH2), 58.4 (C1), 49.9 (NCH2), 28.8 (C2), 26.3
(C3), 24.4 (C5), 23.9 (C4), 20.0 (C6), 7.8 (CH3).
4.6. Insertion reaction
A solution of pyridinium ylid complex 27 (200 mg,
0.4 mmol) in THF (10 ml) was heated at reflux for 3 h.
The solvent was evaporated in vacuo and the crude was
chromatographed (100% CH2Cl2) to afford the 2-benzyl
tetrahydrofurane 31 (54 mg, 0.34 mmol) in 84% yield.
The spectroscopic data of 31 corresponded to those of
the literature [43].
Cyclopropane 49 endo (colourless oil, 32% yield, two
isomers ‘A (major) and B (minor)’: de=10%): 1H-
NMR (400 MHz, CDCl3), the two isomers were not
1
separated by H-NMR l 5.03 (t, J=6.8 Hz, 1H H12),
3.58 (m, 4H, OCH2), 2.58 (m, 2H, NꢀCHH%), 2.48 (m,
2H, NꢀCHH%), 1.98–1.76 (m, 5H, H2, H3, H4, H11,
H11%), 1.61 (s, 3H, H14), 1.53 (s, 3H, H14%), 1.40–1.32 (m,
5H, H2%, H3%, H4%, H8, H9), 1.29–1.21 (m, 2H, H5, H10),
1.20–1.05 (m, 4H, H7, H7%, H8%, H10%), 0.88 (m, 3H, H6),
0.81 (d, J=6.4 Hz, 3H, H15); 13C-NMR (100 MHz,
CDCl3) l 131.1 (C13 (A and B)), 124.5 (C12 (A and B)),
66.8 (OCH2 (A and B)), 59.0 (C1 (A and B)), 49.9
(NCH2 (A and B)), 37.2 (C8 (A and B)), 36.7 (C10 (A)),
36.6 (C10 (B)), 32.0 (C9 (B)), 31.9 (C9 (A)), 31.3 (C6 (A
and B)), 28.6 (C5 (B)), 28.5 (C5 (A)), 26.5 (C4 (A and
B)), 25.3 (C14 (A and B)), 25.1 (C11 (A and B)), 23.8 (C2
(A and B)), 20.4 (C7 (A)), 20.3 (C7 (B)), 20.0 (C3 (A and
B)), 19.2 (C14% (B)), 19.1 (C14% (A)), 17.2 (C15 (A and B)).
To a solution of 4-cyclopent-1-enyl morpholine (311
ml, 1.9 mmol) in CH2Cl2 (10 ml), the nicotinium ylid
complex 42 (0.25 g, 0.48 mmol) was added.
3-Benzyl tetrahydrofurane 31 (colorless oil, 84% yield)
1
[43]: H-NMR (CDCl3, 400 MHz) l 7.31–7.21 (m, 5H,
Ph), 4.09 (m, 1H, OCH), 3.93 (m, 1H, OꢀCHH%), 3.76
(m, 1H, OꢀCHH%), 2.95 (dd, J=13.6 Hz, J%=6.4 Hz,
1H, CHH%ꢀPh), 2.77 (dd, J=13.6 Hz, J%=6.8 Hz, 1H,
CHH%ꢀPh), 1.97–1.83, 1.58 (m, 4H, CH2).
4.7. Cyclopropanation of dihydropyridines and indoles
The reaction of the dihydropyridines 13 with the
carbene complex 50 afforded the pyridinium ylid com-
plex 27, but also to the aminocyclopropane complexes
51 endo (15% CH2Cl2/PE, 89 mg, 0.18 mmol) and 51
exo (20% CH2Cl2/PE, 149 mg, 0.30 mmol) as a yellow
viscous oil in 8% yield.
The solution was refluxed for 2 d and after chro-
matography, 46 exo (1% Et2O/PE, 31 mg, 0.17 mmol)
and 47 endo (20% Et2O/PE, 15 mg, 0.08 mmol) were
obtained as colourless oils in 54% yield.
1
Complex 51 endo (yellow viscous oil, 3% yield): H-
NMR (400 MHz, CDCl3) l 7.53–7.47 (m, 3H, Ph),
7.35–7.25 (m, 2H, Ph), 6.40 (m, 1H, H4), 5.39 (m, 1H,
H3), 3.30 (m, 1H, H6), 3.19 (m, 1H, H1), 3.01 (m, 1H,
H2), 2.65 (dd, J=9.4 Hz, J%=8.4 Hz, 1H, H7), 2.27 (m,
1H, H2%), 1.85 (m, 1H, H5); 13C-NMR (100 MHz,
CDCl3) l 201.0 (CO trans), 198.6 (CO cis), 133.9,
129.7, 128.4, 127.4 (Ph), 125.6 (C4), 124.9 (C3), 53.4
(C2), 48.3 (C6), 27.7 (C7), 15.0 (C5). MS Calc. for
C17H12NO5W (M+) 495. Found: 495.
1
Cyclopropane 46 exo (colourless oil, 36% yield): H-
NMR (400 MHz, CDCl3) l 3.63 (t, J=4.6 Hz, 4H,
OCH2), 2.64 (dt, J=11.2 Hz, J%=4.6 Hz, 2H,
NꢀCHH%), 2.49 (dt, J=11.2 Hz, J%=4.6 Hz, 2H,

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583
1
Complex 51 exo (yellow viscous oil, 5% yield): H-
NMR (400 MHz, CDCl3) l 7.36–7.23 (m, 3H, Ph),
7.10–7.05 (m, 2H, Ph), 6.35 (m, 1H, H4), 5.49 (m, 1H,
H3), 3.58–3.48 (m, 2H, H2, H2%), 3.30 (m, 1H, H6), 3.13
(m, 1H, H1), 2.54 (t, J=4.4 Hz, 1H, H7), 1.77 (m, 1H,
H5); 13C-NMR (100 MHz, CDCl3) l 201.4 (CO trans),
198.4 (CO cis), 137.7, 128.6, 126.7, 125.6 (Ph, C4),
121.5 (C3), 52.4 (C2), 52.0 (C6), 26.3 (C7), 24.1 (C5).
During the reduction reaction of the carbene com-
plex 52, the aminocyclopropane complex 54 exo (25%
CH2Cl2/PE, 72 mg, 0.14 mmol) was obtained as a
yellow viscous oil in 2% yield.
1
Cyclopropane 61 exo (colorless oil, 53% yield): H-
NMR (CDCl3, 400 MHz) l 7.30–7.23 (m, 3H, H12,
H14, H16), 7.18–7.09 (m, 2H, H13, H15), 6.96–6.93 (m,
2H, H4, H5), 6.71 (dt, J=7.2 Hz, J%=1.0 Hz, 1H, H6),
6.55 (d, J=7.2 Hz, 1H, H3), 3.61 (dd, J=6.6 Hz,
J%=2.1 Hz, 1H, H9), 2.98 (s, 3H, CH3), 2.93 (dd,
J=6.6 Hz, J%=3.2 Hz, 1H, H10), 1.20 (dd, J=3.2 Hz,
J%=2.1 Hz, 1H, H8); 13C-NMR (CDCl3, 100 MHz) l
150.5 (C2), 142.5 (C11), 132.5 (C7), 128.5 (C12, C16),
127.1 (C14), 125.3 (C6), 125.1 (C13, C15), 124.1 (C4),
117.7 (C5), 108.3 (C3), 51.4 (C9), 34.22 (C1), 31.9 (C10),
23.4 (C8). HRMS Calc. for C16H15N (M+) 221.1204.
Found: 221.1204.
1
Complex 54 exo (yellow viscous oil, 2% yield): H-
NMR (400 MHz, CDCl3) l 7.35–7.19 (m, 5H, Ph),
6.30 (m, 1H, H4), 5.39 (m, 1H, H3), 3.48 (m, 1H, H4%),
3.30 (m, 1H, H2%), 2.92 (m, 1H, H1), 2.83 (m, 1H, H6),
2.67 (m, 1H, H10), 1.92 (m, 1H, H8), 1.80 (m, 1H, H9),
1.46 (m, 1H, H7), 1.15 (m, 1H, H5), 1.05 (m, 1H, H8%);
13C-NMR (100 MHz, CDCl3) l 201.4 (CO trans), 198.6
(CO cis), 141.95, 128.3, 125.8 (Ph), 128.0 (C4), 120.9
(C3), 52.8 (C2), 50.3 (C6), 35.5 (C10), 30.6 (C8), 30.1
(C9), 22.1 (C7), 19.3 (C5). HRMS Calc. for
C20H19O5NW (M+) 537.0773. Found: 537.0774.
To a solution of the pyridinium ylid complex 27 (350
mg, 0.71 mmol) in CH2Cl2 (15 ml) was added N-methyl
1,2-dihydropyridine [32] (102 mg, 1.1 mmol). After 5
min at room temperature, the crude turned brown and
the solvent was evaporated in vacuo. A chromatogra-
phy afforded the aminocyclopropane 57 exo (100%
Et2O/PE, 24 mg, 0.13 mmol) as a colorless oil in 18%
yield.
4.8. Synthesis of the 3-phenyl quinoline 64
To a solution of pyridinium ylid complex 27 (400 mg,
0.8 mmol) in CH2Cl2 (15 ml) was added indole 62 (3
equiv.). After 2 h at reflux, the solvent was evaporated
in vacuo. Palladium on charcoal (85 mg, 0.1 equiv.) and
toluene (6 ml) were added and the mixture was heated
at reflux for 24 h. The crude was chromatographed on
silica gel (10% AcOEt/PE) to afford the 3-phenyl quin-
oline 64 (93 mg, 0.45 mmol) in 56% yield.
3-Phenyl quinoline 64 [44] (white solid, 56% yield,
m.p. 52°C): 1H-NMR (CDCl3, 400 MHz) l 9.20 (d,
J=2.4 Hz, 1H, H2), 8.29 (d, J=2.4 Hz, 1H, H4), 8.15
(d, J=8.6 Hz, 1H, H5), 7.87 (d, J=8.6 Hz, 1H, H8),
7.73–7.70 (m, 3H, H6, H12, H12%), 7.58–7.51 (m, 3H,
H7, H13, H14), 7.40–7.35 (m, 1H, H13%); 13C-NMR
(CDCl3, 100 MHz) l 150.0 (C2), 147.5 (C9), 138.0 (C3),
133.9 (C11), 133.3 (C4), 129.5 (C7), 129.4 (C12), 129.3
(C8, C10), 128.2 (C5), 128.1 (C14), 127.5 (C13), 127.1
(C6).
Aminocyclopropane 57 exo (colorless oil, 18% yield):
1H-NMR (400 MHz, CDCl3) l 7.41–6.99 (m, 5H, Ph),
6.20 (m, 1H, H4), 5.58 (m, 1H, H3), 3.23 (dd, J=10.1
Hz, J%=4.2 Hz, 1H, H6), 2.90–2.74 (m, 2H, H2, H2%),
2.52 (s, 3H, H1), 2.30 (t, J=4.2 Hz, 1H, H7), 1.72 (m,
1H, H5); 13C-NMR (100 M2Hz, CDCl3) l 141.9, 128.5,
125.6, 125.4 (Ph), 125.8 (C4), 122.0 (C3), 50.1 (C2), 49.0
(C6), 26.8 (C7), 21.3 (C5). MS Calc. for C13H15N (M+)
185. Found: 185.
4.9. Preparation of the alkoxy ketene acetals 67, 77
and 78
The alkoxy ketene acetals 77 and 78 were prepared as
described in the literature [45].
To a solution of pyridinium ylid complex 27 (500 mg,
1.0 mmol) in CH2Cl2 (20 ml) was added N-methyl
indole 60 (1 equiv.). After 12 h at room temperature,
the crude was filtered on Celite and chromatographed
on alumina (1% AcOEt/PE) to afford the cyclopropane
61 (116 mg, 0.53 mmol) in 53% yield and as a single exo
isomer.
4.10. Preparation of the alkoxy ketene acetal 67
In a three-necked flask equipped with a condenser, a
dropping funnel and a mechanical stirrer, (−)-men-
thoxy acetic acid (9.8 ml, 46.7 mmol) in THF (50 ml)
was introduced. This solution was cooled to 0°C and

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H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
pyridine (7 ml) was added. HMDS (10.8 ml, 51.4
mmol) was then added dropwise. After stirring this
white viscous solution during 5 min at 0°C, TMSCl
(2.95 ml, 23.4 mmol) was added slowly. The solution
was stirred 1 h at 0°C and then 20 h at room tempera-
ture. After filtration on Celite, the solvent was evapo-
rated in vacuo and the crude was distilled under
reduced pressure to afford the silylated ester 66 (10.7 g,
37.4 mmol) in 80% yield.
MHz) l 5.01 (s, 1H, H11), 2.95 (td, J=10.8 Hz, J%=4.4
Hz, 1H, H1), 2.05 (heptd, J=7.1 Hz, J%=3.1 Hz, 1H,
H8), 1.84 (m, 1H, H6), 1.44–1.37 (m, 2H, H3, H4),
1.13–1.04 (m, 2H, H2, H5), 0.77–0.58 (m, 3H, H3%, H4%,
H6%), 0.69 (d, J=7.6 Hz, 3H, H9 or H10), 0.67 (d,
J=7.2 Hz, 3H, H7), 0.55 (d, J=7.1 Hz, 3H, H9 or
H10), 0.00 (s, 9H, SiMe3), −0.02 (s, 9H, SiMe3); 13C-
NMR (CDCl3, 100 MHz) l 121.6 (C12), 111.5 (C11),
81.3 (C1), 47.8 (C2), 40.9 (C6), 34.5 (C4), 31.6 (C5), 25.4
(C8), 23.2 (C3), 22.3 (C7), 20.9, 16.2 (C9, C10), 0.7, 0.0
(SiMe3). MS Calc. for C18H38O3Si2 (M+) 358. Found:
358.
4.11. Reactions of the alkoxy ketene acetals 67, 77 and
78 with the pyridinium ylid complexes
Silylated ester 66 (colorless oil, 80% yield, b.p. (0.1
mm Hg) 74°C): H-NMR (CDCl3, 400 MHz) l 3.95 (d,
1
Typical procedure: to a solution of pyridinium ylid
complex 27 (250 mg, 0.5 mmol) in CH2Cl2 (10 ml) was
added, at room temperature, the alkoxy ketene acetal
67 (234 ml, 1.0 mmol). After 5 min, the solution turned
from red to brown. An aqueous solution of sodium
hydroxide (10 ml, 1N) was added. The aqueous phase
was then recuperated and Et2O (10 ml) was added. An
aqueous solution of HCl (1N) was then added until pH
became neutral. Extraction with Et2O, drying (Na2SO4)
and solvent evaporation in vacuo afford the 3-phenyl
prop-2-enoic acid 70 in 90% yield as a mixture of
isomers (ratio E/Z=63/37).
J=16.8 Hz, 1H, H11), 3.87 (d, J=16.8 Hz, 1H, H11%),
2.98 (td, J=10.8 Hz, J%=4.4 Hz, 1H, H1), 2.16 (heptd,
J=7.2 Hz, J%=2.8 Hz, 1H, H8), 1.91 (m, 1H, H6),
1.53–1.42 (m, 2H, H3, H4), 1.21–1.14 (m, 2H, H2, H5),
0.86–0.63 (m, 3H, H3%, H4%, H6%), 0.76 (d, J=6.4 Hz,
3H, H9 or H10), 0.74 (d, J=7.2 Hz, 3H, H7), 0.64 (d,
J=6.8 Hz, 3H, H9 or H10), 0.15 (s, 9H, SiMe3); 13C-
NMR (CDCl3, 100 MHz) l 171.4 (CꢁO), 80.5 (C1), 67.1
(C11), 48.4 (C2), 40.4 (C6), 34.6 (C4), 31.7 (C5), 25.7
(C8), 23.5 (C3), 22.6 (C7), 21.2, 16.5 (C9, C10), 0.0
(SiMe3). MS Calc. for C15H30O3Si (M+) 286. Found:
286.
3-Phenyl prop-2-enoic acid 70 (white solid, 90% yield,
m.p. 133°C) [46].
The same apparatus was used for the synthesis of the
(−)-menthoxy ketene acetal 67. To a solution of
HMDS (7.95 ml, 37.8 mmol) in THF (40 ml) at 0°C
was slowly added nBuLi (15 ml, 37.8 mmol) via a
dropping funnel The solution turned light brown and,
at the end of the addition, the mixture was heated at
45°C for 45 min. The solution was cooled to−78°C in
an acetone–dry ice bath, and the silylated ester 66 (9.0
g, 31.5 mmol) was added dropwise. The reaction
medium was stirred for an additional 30 min at−78°C.
TMSCl (6.0 ml, 47.3 mol) was added dropwise at this
temperature. At the end of the addition, the yellow
viscous solution was allowed to warm up to room
temperature and then stirred for an additional hour.
After filtration on Celite, the solvent was evaporated in
vacuo and the crude was distilled under reduced pres-
sure to afford the (−)-menthoxy ketene acetal 67 (5.3
g, 14.8 mmol) in 47% yield.
Isomer E: 1H-NMR (CDCl3, 400 MHz) l 10.2
(broad s, 1H, CO2H), 7.80 (d, J=16.0 Hz, 1H,
ꢁCHPh), 7.58–7.56 (m, 2H, Ph), 7.43–7.41 (m, 3H,
Ph), 6.46 (d, J=16.0 Hz, 1H, ꢁCHCO).
Isomer Z: 1H-NMR (CDCl3, 400 MHz) l 10.2
(broad s, 1H, CO2H), 7.63–7.61 (m, 2H, Ph), 7.38–7.28
(m, 3H, Ph), 7.08 (d, J=12.4 Hz, 1H, ꢁCHPh),6.98 (d,
J=12.4 Hz, 1H, ꢁCHCO).
All the other conjugated acids were obtained using
the same method.
But-2-enoic acid 79 was obtained from the pyri-
dinium ylid complex 45 and the alkoxy ketene acetal 77
after 36 h in refluxing CH2Cl2 and was isolated in 75%
yield as a mixture of isomers (ratio E/Z=70/30).
But-2-enoic acid 79 (white solid, 75% yield, m.p.
72°C) [47].
Isomer E: 1H-NMR (CDCl3, 400 MHz) l 10.48
(broad s, 1H, CO2H), 7.09 (dq, J=13.8 Hz, J%=7.0
Hz, 1H, ꢁCHꢀCH3), 5.80 (m, 1H, ꢁCHꢀCO), 1.91 (dd,
J=7.0 Hz, J%=1.6 Hz, 3H, CH3).
Isomer Z: 1H-NMR (CDCl3, 400 MHz) l 10.48
(broad s, 1H, CO2H), 6.48 (dq, J=11.6 Hz, J%=7.4
Hz, 1H, ꢁCHꢀCH3), 5.87 (m, 1H, ꢁCHꢀCO), 2.14 (dd,
J=7.4 Hz, J%=1.8 Hz, 3H, CH3).
(−)-Menthoxy ketene acetal 67 (colorless oil, 47%
yield, b.p. (0.1 mm Hg) 94°C): H-NMR (CDCl3, 400
3-Cyclopropyl prop-2-enoic acid 80 was obtained
from the pyridinium ylid complex 18 and the alkoxy
1

H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
585
ketene acetal 77 after 1.5 h in refluxing CH2Cl2 and was
isolated in 83% yield as a mixture of isomers (ratio
E/Z=52/48).
Isomer E: 1H-NMR (CDCl3, 400 MHz) l 11.34
(broad s, 1H, CO2H), 7.88 (q, J=1.6 Hz, 1H, CH),
7.39–7.31 (m, 5H, Ph), 2.16 (d, J=1.6 Hz, 3H, CH3).
Isomer Z: 1H-NMR (CDCl3, 400 MHz) l 11.34
(broad s, 1H, CO2H), 7.39–7.31 (m, 5H, Ph), 6.93 (q,
J=1.0 Hz, 1H, CH), 2.18 (d, J=1.0 Hz, 3H, CH3).
3-Cyclopropyl prop-2-enoic acid 80 (white solid, 83%
yield, m.p. 69°C) [48].
Isomer E: 1H-NMR (CDCl3, 400 MHz) l 11.24
(broad s, 1H, CO2H), 6.54 (dd, J=15.2 Hz, J%=10.0
Hz, 1H, ꢁCHꢀCH), 5.91 (d, J=15.2 Hz, 1H,
ꢁCHꢀCO), 1.63 (m, 1H, CH), 1.00 (m, 2H, CH2), 0.60
(m, 2H, CH2).
4.12. Synthesis of the 9-oxo dec-2-enoic acid 76 ‘queen
substance’
Isomer Z: 1H-NMR (CDCl3, 400 MHz) l 11.24
(broad s, 1H, CO2H), 5.71 (d, J=12.2 Hz, 1H,
ꢁCHꢀCO), 5.59 (d, J=12.2 Hz, 1H, ꢁCHꢀCH), 2.88
(m, 1H, CH), 1.03 (m, 2H, CH2), 0.70 (m, 2H, CH2).
6-Phenyl hex-2-enoic acid 81 was obtained from the
pyridinium ylid complex 53 and the alkoxy ketene
acetal 77 after 4 h in refluxing CH2Cl2 and was isolated
in 61% yield as a mixture of isomers (ratio E/Z=70/
30).
To a solution of 6-bromo hexanoic acid 71 (6.0 g,
30.8 mmol) in THF (230 ml) was added MeLi (92.5 ml,
1.33 N) via a cannula at 0°C following Rubottom’s
method [51]. The solution was stirred during 2 h at 0°C
and then TMSCl (78.1 ml, 0.62 mol) was quickly
added. The reaction mixture was allowed to warm up
to room temperature and HCl (230 ml, 1N) was added.
The crude was extracted with Et2O, washed (water and
brine), dried over Na2SO4 and the solvent was evapo-
rated in vacuo. The 7-bromo heptan-2-one 72 (3.0 g,
15.4 mmol) was obtained after chromatography (30%
Et2O/PE) in 50% yield as a colorless oil. The spectro-
scopic data of 72 corresponded to those reported in the
literature [52].
According to the protocol of Sterzyky [53], a solution
of 7-bromo heptan-2-one 72 (3.0 g, 15.4 mmol) and
glycol (4.3 ml, 77 mmol) in benzene (120 ml) in pres-
ence of a catalytic amount of pyridinium tosylate (780
mg, 20% cat.) was heated at reflux with azeotropic
water removal by a Dean–Stark trap until the starting
ketone 72 had completely converted (TLC control). A
classical work up afforded the 2-(5-bromopentyl)-2-
methyl-1,3-dioxolane 72% (3.5 g, 14.8 mmol) in 96%
yield.
6-Phenyl hex-2-enoic acid 81 (white solid, 61% yield,
m.p. 119°C) [49].
Isomer E: 1H-NMR (CDCl3, 400 MHz) l 10.50
(broad s, 1H, CO2H), 7.35–7.20 (m, 5H, Ph), 7.14 (dt,
J=15.3 Hz, J%=7.1 Hz, 1H, ꢁCHꢀCH2), 5.88 (d,
J=15.3 Hz, 1H, ꢁCHꢀCO), 2.69 (m, 2H, CH2Ph), 2.30
(m, 2H, CH2ꢀCHꢁ), 1.85 (m, 2H, CH2).
Isomer Z: 1H-NMR (CDCl3, 400 MHz) l 10.50
(broad s, 1H, CO2H), 7.35–7.20 (m, 5H, Ph), 6.41 (dt,
J=11.7 Hz, J%=7.6 Hz, 1H, ꢁCHꢀCH2), 5.85 (d,
J=11.7 Hz, 1H, ꢁCHꢀCO), 2.75 (m, 2H, CH2Ph), 2.45
(m, 2H, CH2ꢀCHꢁ), 1.71 (m, 2H, CH2).
5-(S)-Methyl hept-2-enoic acid 82 was obtained from
the pyridinium ylid complex 36 and the alkoxy ketene
acetal 77 after 3 h in refluxing CH2Cl2 and was isolated
in 62% yield as a mixture of isomers (ratio E/Z=53/
47).
2-(5-Bromopentyl)-2-methyl-1,3-dioxolane 72% [52]
1
(colorless oil, 96% yield): H-NMR (CDCl3, 400 MHz)
5-(S)-Methyl hept-2-enoic acid 82 (white solid, 83%
yield, m.p. 83°C, [h]D= +13.3°).
l 3.92 (m, 4H, CH2ꢀCꢀO), 3.39 (t, J=7.0 Hz, 2H,
CH2Br), 1.82 (q, J=7.0 Hz, 2H, CH2ꢀCH2Br), 1.61 (m,
2H, CH2), 1.43–1.35 (m, 4H, CH2), 1.29 (m, 3H, CH3).
A solution of dioxolane 72% (3.4 g, 14.5 mmol) and
NaI (6.45 g, 43.5 mmol) was heated in refluxing acetone
(100 ml) for 5 h. A classical work up afforded the
2-(5-iodopentyl)-2-methyl-1,3-dioxolane 73 in 89%
yield.
Isomer E: 1H-NMR (CDCl3, 400 MHz) l 11.30
(broad s, 1H, CO2H), 7.09 (dt, J=15.2 Hz, J%=7.6 Hz,
1H, ꢁCHꢀCH2), 5.86 (m, 1H, ꢁCHꢀCO), 2.25 (m, 1H,
CHH%ꢀCHꢁ), 2.09 (m, 1H, CHH%ꢀCHꢁ), 1.72–1.17 (m,
3H, CH, CH2), 0.93–0.88 (m, 6H, CH3).
Isomer Z: 1H-NMR (CDCl3, 400 MHz) l 11.30
(broad s, 1H, CO2H), 6.40 (dt, J=11.6 Hz, J%=7.6 Hz,
1H, ꢁCHꢀCH2), 5.82 (m, 1H, ꢁCHꢀCO), 2.68 (m, 1H,
CHH%ꢀCHꢁ), 2.56 (m, 1H, CHH%ꢀCHꢁ), 1.72–1.17 (m,
3H, CH, CH2), 0.93–0.88 (m, 6H, CH3). HRMS Calc.
for C8H14O2 (M+) 142.0993. Found: 142.0991.
2-Methyl 3-phenyl prop-2-enoic acid 83 was obtained
from the pyridinium ylid complex 30 and the alkoxy
ketene acetal 78 after 12 h in refluxing CH2Cl2 and was
isolated in 79% yield as a mixture of isomers (ratio
E/Z=82/18).
2-(5-Iodopentyl)-2-methyl-1,3-dioxolane
73
[54]
1
(colorless oil, 89% yield): H-NMR (CDCl3, 400 MHz)
l 3.91 (m, 4H, CH2-CꢀO), 3.17 (t, J=7.0 Hz, 2H,
CH2Br), 1.82 (m, 2H, CH2ꢀCH2I), 1.62 (m, 2H, CH2),
1.46–1.34 (m, 4H, CH2), 1.29 (m, 3H, CH3).
The Fischer method used for the synthesis of carbene
complex 17 was applied to the dioxolane 73. The
carbene complex 74 (3.0 g, 5.6 mmol) was obtained
after purification on silica gel (100% PE) in 46% yield.
Carbene complex 74 (orange oil, 46% yield): 1H-
NMR (CDCl3, 400 MHz) l 4.86 (q, J=7.0 Hz, 2H,
OCH2CH3), 3.91 (m, 4H, OCH2), 3.17 (t, J=7.8 Hz,
2-Methyl 3-phenyl prop-2-enoic acid 83 (white solid,
79% yield, m.p. 81°C) [50].

586
H. Rudler, T. Durand-Re´6ille / Journal of Organometallic Chemistry 617–618 (2001) 571–587
M. Mori, K.C. Nicolaou, J.H. Pawlow, R.R. Schrock, L.E.
Strong, D. Tindall, K.B. Wagner, in: A. Fu¨rstner (Ed.), Alkene
Metathesis in Organic Synthesis, Springer, Bertlin Heidelberg,
1998. (c) K.J. Ivin, J.C. Mol, Olefin Metathesis and Metathesis
Polymerization, Academic Press, San Diego, 1997. (d) M. Schus-
ter, S. Blechert, Angew. Chem. 109 (1997) 2124–2144; Angew.
Chem., Int. Ed. Engl. 36 (1997) 2036.
2H, ꢁCꢀCH2), 1.63–1.18 (m, 8H, CH2), 1.59 (t, J=7.0
Hz, 3H, OCH2ꢀCH3), 1.29 (s, 3H, CH3); 13C-NMR
(CDCl3, 100 MHz) l 334.2 (WꢁC), 203.4 (CO trans),
197.4 (CO cis), 110.0 (OꢀCꢀO), 80.7 (OCH2CH3), 65.0
(ꢁCꢀC), 64.7 (OCH2), 39.3, 39.0, 26.4, 23.8 (CH2), 23.7
(OꢀC(O)ꢀCH3), 14.8 (OꢀCꢀCH3). HRMS Calc. for
C17H22O8W (M+) 538.0824. Found: 538.0827.
A freshly prepared solution of dihydropyridines 13 was
added to a solution of complex 74 (2.9 g, 5.4 mmol) in
Et2O (40 ml). After 5 min at room temperature, the
reaction was complete (TLC control). The crude was
chromatographed (40% CH2Cl2/PE) and the pyridinium
ylid complex 75 (2.51 g, 4.4 mmol) was obtained as an
orange solid in 82% yield.
[2] (a) M.P. Doyle, D.C. Forbes, Chem. Rev. 98 (1998) 911–935. (b)
A.B. Charrette, J.F. Marcoux, Synlett (1995) 1197. (c) H.M.L.
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Organic Chemistry, Vol. 4, Pergamon Press, New York, 1991,
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M.R. Churchill, J. Am. Chem. Soc. 122 (2000) 3063 and refer-
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buckle, Chem. Rev. 91 (1991) 298–308. (b) I. Zugravescu, M.
Petrovanu, N-Ylide Chemistry, McGraw-Hill, New York, 1976.
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1945.
Pyridinium ylid complex 75 (orange solid, 82% yield,
1
m.p. 129°C): H-NMR (CDCl3, 400 MHz) l 8.52 (d,
J=6.0 Hz, 2H, Ho py.), 7.85 (t, J=6.0 Hz, 1H, Hp py.),
7.54 (t, J=6.0 Hz, 2H, Hm py.), 4.67 (dd, J=10.0 Hz,
J%=5.2 Hz, 1H, WꢀCꢀH), 3.92 (m, 4H, CH2O), 2.63 (m,
1H, WꢀCꢀCHH%), 2.45 (m, 1H, WꢀCꢀCHH%), 1.61 (t,
J=8.0 Hz, 2H, CH2ꢀC(O)ꢀO), 1.38–1.21 (m, 6H, CH2),
1.30 (s, 3H, CH3); 13C-NMR (CDCl3, 100 MHz) l 204.6
(CO trans), 202.0 (CO cis), 140.0, 136.6, 126.9 (py.),
110.1 (OꢀCꢀO), 64.7 (CH2O), 64.4 (WꢀC), 44.0, 39.2,
29.6, 29.3, 24.0 (CH2), 23.8 (CH3). HMRS calcd for
C20H23NO7W (M+) 573.0984. Found: 573.0987.
To a solution of the pyridinium ylid complex 75 (1 g,
1.7 mmol) in CH2Cl2 (20 ml) was added the alkoxy ketene
acetal 77 (817 mg, 3.4 mmol). The solution was heated
at reflux during 48 h and then the conjugated acid was
recovered as above. The solvent was evaporated in vacuo
and dioxane (10 ml) and HCl (2 ml, 2N) were added to
perform the ketone deprotection. The reaction mixture
was heated at reflux during 10 h. After a classical work
up, the 9-oxo dec-2-enoic acid 76 (105 mg, 2.21 mmol)
was obtained in 65% yield as a mixture of isomers (ratio
E/Z=80/20).
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9-Oxo dec-2-enoic acid 76 [40] ‘queen substance’ (white
solid, 65% yield, m.p. 54°C). The spectroscopic data of
76 corresponded to those of the literature.
Isomer E: 1H-NMR (CDCl3, 400 MHz) l 10.21 (broad
s, 1H, CO2H), 7.04 (dt, J=15.2 Hz, J%=7.2 Hz, 1H,
ꢁCHꢀCH2), 5.80 (d, J=15.2 Hz, 1H, ꢁCHꢀCO), 2.41 (m,
2H, CH2ꢀCHꢁ), 2.22 (m, 2H, CH2ꢀCO), 2.13 (s, 3H,
CH3), 1.58–1.20 (m, 6H, CH2).
Isomer Z: 1H-NMR (CDCl3, 400 MHz) l 10.21 (broad
s, 1H, CO2H), 6.32 (dt, J=11.6 Hz, J%=7.2 Hz, 1H,
ꢁCHꢀCH2), 5.77 (d, J=11.6 Hz, 1H, ꢁCHꢀCO), 2.64 (m,
2H, CH2ꢀCHꢁ), 2.44 (m, 2H, CH2ꢀCO), 2.13 (s, 3H,
CH3), 1.64–1.38 (m, 6H, CH2).
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