One-pot transformation of silyl enol ethers into 1,3-dienes: In situ generation of alkenyl nonaflates and subsequent Heck reactions - Scope and limitations

Article abstract of DOI:10.1002/1099-0690(200211)2002:21<3646::AID-EJOC3646>3.0.CO;2-D

Palladium-catalysed reactions between methyl acrylate and the isolated alkenyl nonaflates 2a, 2d and 2e proceed without difficulties, furnishing the desired 1,3-dienes 3, 14 and 15 in good yields. The use of other alkenyl nonaflates and olefins in this Heck reaction was also examined. The main purpose of this study was the development of an in situ generation of the required alkenyl nonaflates 2 from the corresponding silyl enol ethers 1 and their one-pot transformation into 1,3-dienes. Thus, the previously described fluoride-promoted exchange of the trimethylsilyl substituent of typical enol ethers 1 for a nonafluorobutylsulfonyl group was directly combined with the palladium-catalysed coupling step. This sequence allowed the efficient transformation of a variety of silyl enol ethers 1 into highly substituted 1,3-dienes in a practical one-pot procedure. The scope and limitations, together with the chemo- and stereoselectivity, of this process are discussed. A particular intriguing example involves a one-pot synthesis of silyl enol ether 1j by means of a Diels-Alder reaction, subsequent nonaflation and a Heck reaction with tert-butyl acrylate, furnishing the highly functionalised 1,3-diene 30 in good overall yield. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.

Full text of DOI:10.1002/1099-0690(200211)2002:21<3646::AID-EJOC3646>3.0.CO;2-D

FULL PAPER
One-Pot Transformation of Silyl Enol Ethers into 1,3-Dienes:
In situ Generation of Alkenyl Nonaflates and Subsequent Heck Reactions ؊
Scope and Limitations[‡]
Ilya M. Lyapkalo,[a] Matthias Webel,[b][‡] and Hans-Ulrich Reißig*[a]
Keywords: Alkenyl nonaflates / Dienes / Fluorides / Palladium catalysis / Silyl enol ethers
Palladium-catalysed reactions between methyl acrylate and
allowed the efficient transformation of a variety of silyl enol
the isolated alkenyl nonaflates 2a, 2d and 2e proceed without
ethers 1 into highly substituted 1,3-dienes in a practical one-
difficulties, furnishing the desired 1,3-dienes 3, 14 and 15 in pot procedure. The scope and limitations, together with the
good yields. The use of other alkenyl nonaflates and olefins
in this Heck reaction was also examined. The main purpose
of this study was the development of an in situ generation of
the required alkenyl nonaflates 2 from the corresponding si-
chemo- and stereoselectivity, of this process are discussed. A
particular intriguing example involves a one-pot synthesis of
silyl enol ether 1j by means of a Diels−Alder reaction, sub-
sequent nonaflation and a Heck reaction with tert-butyl ac-
lyl enol ethers 1 and their one-pot transformation into 1,3- rylate, furnishing the highly functionalised 1,3-diene 30 in
dienes. Thus, the previously described fluoride-promoted ex-
change of the trimethylsilyl substituent of typical enol ethers
1 for a nonafluorobutylsulfonyl group was directly combined
with the palladium-catalysed coupling step. This sequence
good overall yield.
( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany,
2002)
Introduction
wards the development of one-pot conversions of silyl enol
ethers 1 into the corresponding 1,3-dienes, via the interme-
diary stage of alkenyl nonaflates 2, by Heck coupling, as
illustrated in Scheme 1. Other palladium-catalysed one-pot
reactions such as the Suzuki coupling will be described in
forthcoming publications.[7,10]
The Heck reaction, introduced in 1968, has meanwhile
become textbook knowledge.[1] This palladium-catalysed re-
action between alkenes and alkenyl and aryl halides pro-
vides a variety of unsaturated systems of great importance
in organic synthesis, as demonstrated in numerous applica-
tions.[2] The required alkenyl halides are very often unavail-
able under straightforward and mild reaction conditions,
and so the corresponding alkenyl triflates, which can be pre-
pared with good selectivity from carbonyl compounds, are
extremely useful alternatives.[3] Alkenyl nonaflates (nona-
fluorobutanesulfonates) 2 behave very similarly, but their
transition metal-catalysed coupling reactions have been
studied in only a few cases.[4] We have recently reported that
a variety of structurally rather diverse alkenyl nonaflates 2
can be prepared by fluoride-promoted conversion of silyl
enol ethers
1 with nonafluorobutylsulfonyl fluoride
(NfF).[5] This reagent is commercially available and presents
several advantages, as described in our preceding
reports.[5Ϫ9] We now wish to present our efforts aimed to-
Scheme 1
[‡]
See ref.[7]
[a]
Freie Universität Berlin, Institut für Chemie Ϫ Organische
Chemie,
Heck Reactions of Isolated Alkenyl Nonaflates
Takustr. 3, 14195 Berlin, Germany
E-mail: hans.reissig@chemie.fu-berlin.de
[b]
Institut für Organische Chemie der Technischen Universität
We first examined Heck reactions between isolated alk-
enyl nonaflates 2aϪ2e and typical olefins, in order to estab-
Dresden,
01062 Dresden, Germany
3646
 2002 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim 1434Ϫ193X/02/1121Ϫ3646 $ 20.00ϩ.50/0 Eur. J. Org. Chem. 2002, 3646Ϫ3658

One-Pot Transformation of Silyl Enol Ethers into 1,3-Dienes
FULL PAPER
lish appropriate coupling conditions for the planned one- of 1,3-diene 4. Finally, 2a and but-3-en-1-yl acetate gave the
pot transformation. For these purposes we used the phos- expected coupling product 5 as a mixture of E and Z iso-
phane-free catalytic system with palladium() acetate as mers, together with deconjugated diene 6 as a side product.
source of palladium(0), mostly in dimethylformamide or di- Reaction conditions B were highly efficient, providing a
methylformamide/tetrahydrofuran mixtures as solvent, and 91% yield of 5 and 6. The formation of 6 is evidence of the
employing the following modifications:
expected low regioselectivity of the reductive elimination of
Conditions A Ϫ potassium carbonate, tetra-n-butylam- palladium during the final step of this Heck reaction.[2a]
monium chloride at room temperature (Jeffery’s condi- The combination of 2a with butyl vinyl ether under condi-
tions);[2e]
tions B was less successful, and afforded (after hydrolysis of
Conditions B Ϫ potassium carbonate, potassium acetate the primary coupling product) 1-acetylcyclopentene only in
at temperatures between 60 and 85 °C;[11]
Conditions CϪ triethylamine, lithium chloride at room
low yield.[7]
The coupling of the dihydronaphthalene derivative 2b
temperature or with heating (less expensive, modified Jef- with methyl acrylate under the mild conditions A afforded
fery’s conditions). the expected compound 7 in very small quantities, naph-
Conditions A and C were only employed with electron- thalene derivative 8 instead being isolated as the major
deficient alkenes such as methyl acrylate, and provided component, albeit only in moderate yield. Apparently,
better yields than conditions B. These last conditions were aromatization of the primary Heck coupling product 7 ow-
only efficient at elevated temperatures, although they are ing to a (palladium-catalysed) dehydrogenation reaction
more generally applicable, including alkenes not substituted takes place under the reaction conditions (Scheme 2, last
with electron-withdrawing substituents.
example).
Model alkenyl nonaflate 2a was successfully combined
The pinacolone-derived nonaflate 2c also proved to be a
with methyl acrylate under conditions A to furnish 1,3-di- special case. Whereas we later found appropriate conditions
ene 3 in excellent yield (Scheme 2). Conditions B were used that allowed isolation of the expected diene 9 in moderate
to couple 2a to an acrylamide bearing a camphor-derived yield (see below) the palladium() acetate-catalysed reac-
chiral auxiliary, which resulted in highly efficient formation tion between 2c and methyl acrylate in the presence of li-
thium chloride and triethylamine as base furnished
DielsϪAlder adducts 10, derived from the intermediate 1,3-
diene 9 and methyl acrylate, in good yields (Scheme 3).
Cyclohexene derivatives 10a and 10b were formed in a 1:4.6
ratio and in 78% overall yield. The assumption that the two
isomers were diastereomers could be confirmed by base-
catalysed isomerization of pure 10a, which again produced
a mixture of the two isomers, now in a 1:7 ratio. The consti-
tution of the DielsϪAlder adducts and thus the regioselec-
tivity of the cycloaddition could be established by oxidation
of 10b with DDQ, which afforded dimethyl 4-(tert-butyl)-
phthalate (13) in 89% yield.[12] The crude product of this
reaction showed the presence of a symmetrical isomer in
the 3Ϫ4% range, possibly the product of a regioisomer un-
detectable in the primary reaction mixture.[13] The regiose-
lectivity of the DielsϪAlder reaction between 1,3-diene 9
and methyl acrylate is thus in the range of 95:5. This high
selectivity and the mildness of the conditions were quite
surprising,[14] although we did not further examine whether
this is a result of palladium and/or lithium chloride accel-
Scheme 2. A: Pd(OAc)2, nBu4NCl, K2CO3, DMF, room temp.; B:
Pd(OAc)2, KOAc, K2CO3, DMF
Scheme 3. C: Pd(OAc)2, LiCl, Et3N, THF, 58 °C, 60 h
Eur. J. Org. Chem. 2002, 3646Ϫ3658
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I. M. Lyapkalo, M. Webel, H.-U. Reißig
FULL PAPER
eration or a consequence of the higher preference of the unproblematic behaviour in coupling reactions (see
required s-cis conformation of 9 due to the presence of the Scheme 2). An exchange of the trimethylsilyl group in 1a
bulky 3-tert-butyl group.
for a nonafluorobutylsulfonyl substituent was achieved, as
The coupling between 2c and methyl acrylate provided a reported earlier, with nonafluorobutylsulfonyl fluoride
further side product: chromatography permitted the isola- (NfF) in the presence of substoichiometric amounts of
tion of pure methyl (E)-6,6-dimethylhept-2-en-4-ynoate nBu4NF at room temperature. After 16 h, the coupling
(12)[15] in 7% yield. Although mechanistically not at all partner and the ingredients for the Heck reaction were ad-
clear, we assume that this compound arises from an oxidat- ded to the resulting solution of 2a, and the mixture was
ive coupling of methyl acrylate with 3,3-dimethylbutyne treated as indicated in Scheme 5. This one-pot procedure
(11), which is in turn generated by base-induced elimination furnished 1,3-dienes 3, 4, 16 and 17 with methyl acrylate,
of nonafluorobutanesulfonic acid (NfOH) from 2c.[16]
the chiral acrylamide, styrene or vinyl acetate as coupling
We also examined coupling reactions between 1,3-buta- partners. The yields were generally quite satisfactory, with
dien-2-yl nonaflate and methyl acrylate or styrene, which only the coupling with vinyl acetate proceeding in low yield
might have produced interesting cross-conjugated trienes. and resulting in an E/Z mixture.
However, all attempts to perform these reactions resulted
only in unidentifiable product mixtures.[7]
Gratifyingly, Heck reactions between aldehyde-derived
alkenyl nonaflates 2d and 2e and methyl acrylate proceeded
without any problems (Scheme 4). Conditions A furnished
the expected 1,3-dienes 14 and 15 in very good yields. Re-
markably, the E/Z ratio observed in 2d was completely
transferred to the coupling product 14. Thus, the alkenyl
nonaflates react under these mild conditions with an excel-
lent degree of retention of configuration. The formation of
the second disubstituted double bond resulting from reduct-
ive elimination of palladium proved to be exclusively E
(with the exception of the reaction giving 5), thereby fa-
vouring minimum steric interactions during the elimina-
tion step.[17]
Scheme 5. A: Pd(OAc)2, nBu4NCl, K2CO3, DMF, room temp., 6 h;
B: Pd(OAc)2, KOAc, K2CO3, DMF, 6 h; D: nBu4NF, NfF, THF,
room temp., 16 h
Not surprisingly, the coupling of the closely related trime-
thylsiloxycyclohexene (1f) with methyl acrylate and with
styrene gave 1,3-dienes 18 and 19 with similar efficiency. We
also examined the conversion of tert-butyldimethylsiloxycy-
clohexene (1fЈ) into a nonaflate with subsequent Heck
coupling (Scheme 6). As demonstrated earlier, the standard
fluoride-promoted exchange reaction only operates with tri-
methylsilyl derivatives, and not with sterically more
Scheme 4. A: Pd(OAc)2, nBu4NCl, K2CO3, DMF, room temp., 6 h
One-pot Transformations of Silyl Enol Ethers
into 1,3-Dienes
The actual purpose of this study was the development of hindered trialkylsilyl groups.[7] However, the potassium
an efficient one-pot procedure for the synthesis of synthetic- cyclohexen-1-olate generated by treatment of 1fЈ with pot-
ally valuable 1,3-dienes. Apparently, the main point of con- assium ethoxide[18] could be trapped with NfF, and the in-
cern was the compatibility of the reagents required for the termediate nonaflate 2f was directly coupled with methyl
first nonaflation step Ϫ i.e., the fluoride promoters and ex- acrylate to provide the 1,3-diene 18 in 68% overall yield.
cess of NfF Ϫ with the activity of the palladium catalysts This experiment thus demonstrates that silyl enol ethers
involved in the second coupling step. The following ex- with sterically more demanding silyl groups can also be
amples demonstrate the scope and limitations of this one- used in a modified one-pot procedure.
pot process. We started with cyclic silyl enol ether 1a be-
With 4-tert-butylcyclohexene derivative (1g), Heck coup-
cause the intermediate nonaflate 2a has shown particularly ling with methyl acrylate furnished the desired 1,3-diene 20
3648
Eur. J. Org. Chem. 2002, 3646Ϫ3658

One-Pot Transformation of Silyl Enol Ethers into 1,3-Dienes
FULL PAPER
Scheme 7. B: Pd(OAc)2, KOAc, K2CO3, DMF; D: nBu4NF, NfF,
THF, room temp., 16 h
(Z)-26 and 27 in 51% yield. Both reactions proceeded less
cleanly, and compounds 25 to 27 could not be isolated in
analytically pure form. One-pot nonaflation/coupling reac-
tions of 1h were also performed with acrylonitrile and di-
methyl vinyl phosphonate as acceptor olefins, but the
formed 1,3-dienes were not obtained in pure form.[7]
The one-pot reactions starting with silyl enol ethers 1i
and 1c, derived from methyl ketones, turned out to be more
complex. Nonaflation of 1i, induced by KF in the presence
of dibenzo-18-crown-6, was found to be efficient,[5] and
subsequent Heck reaction (conditions C) resulted in com-
plete conversion of the intermediate isopropenyl nonaflate
2i after 17 h at room temperature (1H NMR monitoring).
However, the expected coupling product 28 was isolated
only in 30% yield (Scheme 8). Probably, 2i undergoes
elimination of NfOH as a competing reaction under the
conditions applied (see the formation of 11 from 1c).
Scheme 6. A: Pd(OAc)2, nBu4NCl, K2CO3, DMF, room temp., 6 h;
B: Pd(OAc)2, KOAc, K2CO3, DMF; C: Pd(OAc)2, LiCl, Et3N,
DMF; D: nBu4NF, NfF, THF, room temp., 16 h; E: dibenzo-18-
crown-6, KF, NfF, DMF, room temp., 60 h
in good yield, whereas phenyl vinyl sulfone as the acceptor
component provided the expected 1,3-diene 21 (73% yield)
along with an isomeric 1,3-diene 22 (13% yield). Compound
22 was probably formed by proton migration under the re-
action conditions employed. The constitution and config-
uration as given were unequivocally established by 1H
NMR spectroscopy by NOE.
The one-pot procedure was next examined with 1-trime-
thylsiloxycycloheptene (1h) as starting material. Here,
again, couplings with methyl acrylate and styrene to 1,3-
dienes 23 and 24 proceeded with good overall yields
(Scheme 7). We also tested disubstituted olefins as ac-
Scheme 8. C: Pd(OAc)2, LiCl, Et3N, DMF/THF, room temp.; E:
dibenzo-18-crown-6, KF, NfF, room temp.
3,3-Dimethylbuten-2-yl nonaflate (2c), generated from si-
ceptors in Heck couplings with 1h. As expected, the trans- lyl enol ether 1c, required 64 h at room temperature to
formations were not very efficient. Methyl crotonate gave achieve complete conversion, probably due to steric hind-
1
1,3-diene 25 in only 40% yield, whilst methyl methacrylate rance at the reacting centre. H NMR monitoring of the
afforded a mixture of the three coupling products (E)-26, reaction indicated appreciable amounts of 3,3-dimethylbu-
Eur. J. Org. Chem. 2002, 3646Ϫ3658
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I. M. Lyapkalo, M. Webel, H.-U. Reißig
FULL PAPER
tyne[19] 11 formed during the reaction by a base-induced
elimination of NfOH from intermediate 2c.[16] As a result,
the 1,3-diene 9 was obtained in only 46% yield. Our at-
tempts to improve the yield of 9 in experiments with isol-
ated 2c revealed that a highly polar solvent such as di-
methylformamide favours elimination of NfOH even at
room temperature.[20] When the less polar tetrahydrofuran
was used as solvent, neither the Heck reaction nor the elim-
ination took place at room temperature. At 58 °C the coup-
ling became highly predominant over the elimination, but
the subsequent DielsϪAlder reaction between 9 and methyl
acrylate was also accelerated under the employed condi-
tions, producing cyclohexene derivative 10 (see Scheme 3).
So far we have not performed further experiments to optim-
ise the synthesis of 1,3-diene 9.
Aldehyde-derived silyl enol ethers 1d and 1e behaved as
anticipated in view of the results obtained with isolated alk-
enyl nonaflates already presented in Scheme 4. Heck reac-
tions (conditions A) with methyl acrylate afforded the ex-
pected 1,3-diene esters 14 and 15 in good to excellent yields.
Styrene could be coupled under conditions B to furnish 29
in 80% yield (Scheme 9). With respect to the stereoselectiv-
ity of these processes, they occur, as already stated above,
with excellent retention of the double bond configuration
introduced via the silyl enol ether and with high E selectiv-
ity with respect to the newly formed disubstituted double
bond bearing the methoxycarbonyl or the phenyl group.
Scheme 10
beneficial properties of silyl enol ethers, in particular their
regio- and stereoselective preparation combined with the
possibility of purification by distillation or chromatography.
Of particular value are the nonaflate intermediates pro-
duced via aldehyde-derived silyl enol ethers. Formation and
trapping of aldehyde enolates is generally not very product-
ive or even impossible.
The stereoselectivity provided by the silyl enol ethers has
already been exploited for the synthesis of 1,3-dienes 14 and
29 (Scheme 9). In addition, we were recently able to demon-
strate that highly enantioenriched 1,3-dienes of type 20
(Scheme 6) can be prepared by enantioselective depro-
tonation of ketones such as 4-tert-butylcyclohexanone, af-
fording silyl enol ether 1g in approximately 90% ee.[9] This
enantioselectivity obtained in the deprotonation step was
completely transferred to the corresponding coupling prod-
ucts.
A further advantage of the use of silyl enol ethers lies in
the variety of methods available for their preparation. It is
not just the deprotonation of carbonyl compounds; they
can also be generated by conjugate addition of nucleophiles
such as cuprates to α,β-unsaturated carbonyl com-
pounds,[21] and DielsϪAlder reactions may also deliver
highly substituted and functionalised silyl enol ethers. To
demonstrate the potential of this approach, we performed
the [4 ϩ 2] cycloaddition between 2-trimethylsiloxy-1,3-bu-
tadiene and dimethyl fumarate, which efficiently provided
the siloxycyclohexene derivative 1j (Scheme 11).[22] Its in
situ nonaflation occurred under slightly modified condi-
tions to provide nonaflate 2j, and the final Heck reaction
Scheme 9. A: Pd(OAc)2, nBu4NCl, K2CO3, DMF, room temp., 6 h;
B: Pd(OAc)2, KOAc, K2CO3, DMF, 75 °C, 6 h; D: nBu4NF, NfF,
THF, room temp., 16 h
Nonaflates derived from ketones may also be generated
directly by deprotonation of the corresponding carbonyl
compounds and trapping with a nonaflating reagent such
as NfF. We were actually able to demonstrate that nonaflate
2f, produced from cyclohexanone, LDA and quenching
with NfF, can be used without isolation in a Heck reaction
with styrene (Scheme 10). Under conditions B, the expected
diene 19 was isolated in an overall yield of 51%.
What are the advantages of our ‘‘detour’’ via silyl enol
ethers? Our method allows for the exploitation of all the Scheme 11
3650
Eur. J. Org. Chem. 2002, 3646Ϫ3658

One-Pot Transformation of Silyl Enol Ethers into 1,3-Dienes
FULL PAPER
was performed with tert-butyl acrylate under conditions C. dehydes such as 1d and 1e furnished the expected products
These three steps were performed as a one-pot reaction and in good yield. We encountered complications in the coup-
they furnished 1,3-diene 30 in a satisfactory 59% overall ling reactions of dihydronaphthalene nonaflate 2b and of
yield.
the pinacolone-derived nonaflate 2c. The latter was convert-
A similar motivation prompted us to study the siloxydi- ible into diene 9, but under conditions C a DielsϪAlder
ene 1k, which was smoothly prepared from a carvone-de- reaction with methyl acrylate gave the cyclohexene derivat-
rived α,β-unsaturated enone. The DielsϪAlder reaction ive 10 as a subsequent product. However, it proved possible
with N-phenyl maleimide gave the tricyclic endo-cycload- to establish appropriate conditions (see Scheme 8, condi-
duct 1l (Scheme 12).[23] This intermediate could be chemo- tions E combined with C at room temperature) under which
selectively converted into the nonaflate 2l without cleavage the methyl ketone-based silyl enol ethers 1c and 1i were
of the trimethylsilyl group of the tertiary alcohol. Unfortu- converted into the corresponding 1,3-dienes 9 and 28 in
nately, nonaflate 2l proved to be inert under various condi- moderate to low yield. Of particular interest are reaction
tions, and all attempts to perform Heck couplings with sequences involving DielsϪAlder reactions to deliver the si-
methyl acrylate or styrene resulted only in the recovery of lyl enol ether unit. The one-pot transformation of 2-trime-
2l. We assume that this low reactivity is due to the extremely thylsiloxy-1,3-butadiene via the cyclohexene derivatives 1j
high steric shielding around the hindered tetrasubstituted and 2j, followed by coupling with tert-butyl acrylate, pro-
alkene moiety.
ceeded smoothly, giving the highly functionalised diene 30
in good overall yield. Without the necessity to isolate or
purify the intermediate alkenyl nonaflates, our one-pot
transformations make a variety of synthetically useful 1,3-
dienes available in a straightforward, selective and efficient
manner.
Experimental Section
General Methods: For general information see refs.[5,8]
The drying of nBu4NF solution in THF (1 mmol·mLϪ1, Aldrich
or Fluka, contains 3% water) is described in our preceding publica-
tion.[8] Alkenyl nonaflates 2 are synthesised as previously described
by us.[5] The nonaflation and Heck coupling reactions were rou-
tinely conducted under an atmosphere of argon in heat-gun-dried
reaction flasks, although the presence of air did not appreciably
affect the Heck coupling reaction results[17] in a few comparative
experiments. When applicable, the addition of the components was
performed by syringe.
But-3-en-1-yl acetate[24] and (1R,2S,4S)-(N-propenoyl)bornane-
10,2-sultam[25] were synthesised as described in the literature.
Phenyl vinyl sulfone (Ͼ98%) was used as purchased from Fluka.
Heck Coupling Reactions with Isolated Nonaflates 2 ؊ General Pro-
cedure 1 (GP1): A mixture of the corresponding nonaflate 2, base,
additive, olefin and Pd(OAc)2 (4Ϫ8 mol %) in the solvent or the
solvent mixture was stirred under the conditions described in the
individual experiments. After aqueous workup and extraction with
EtOAc or n-pentane, the pure product was isolated by column
chromatography (CC) or kugelrohr distillation unless stated other-
wise. The bases K2CO3 or Et3N and the additives KOAc, nBu4NCl
or LiCl were used in different combinations as described below.
Scheme 12. B: Pd(OAc)2, KOAc, K2CO3, DMF, 24 h; C: Pd(OAc)2,
LiCl, Et3N, DMF, 20 h; E: dibenzo-18-crown-6, KF, NfF, DMF/
THF, room temp., 67 h
Conclusion
Methyl (E)-3-(Cyclopent-1-enyl)propenoate (3): This compound was
prepared by GP1, a mixture of nonaflate 2a (0.366 g, 1.00 mmol),
nBu4NCl (0.278 g, 1.00 mmol), K2CO3 (0.345 g, 2.50 mmol),
Pd(OAc)2 (0.015 g, 0.07 mmol) and methyl acrylate (0.258 g,
3.00 mmol) in DMF (5 mL) being stirred at 25 °C for 7 h. After
the usual workup and CC (hexane/EtOAc, 10:1), product 3 was
furnished (0.133 g, 88% yield) as a yellowish solid, m.p. 33Ϫ34 °C
(ref.[26] 36.5Ϫ37.5 °C). 1H NMR (200 MHz, CDCl3): δ ϭ 1.96
(quint., J ϭ 7.5 Hz, 2 H, CH2), 1.88Ϫ2.58 (m, 4 H, 2 CH2), 3.74
(s, 3 H, CO2Me), 5.72 (d, J ϭ 15.5 Hz, 1 H, 2-H), 6.17 (mc, 1 H,
On the basis of our previously described fluoride-pro-
moted exchange of the trimethylsilyl substituent of enol
ethers for a nonafluorobutylsulfonyl group and a sub-
sequent Heck reaction we have been able to establish an
efficient one-pot procedure that converts silyl enol ethers 1
into a variety of 1,3-dienes. Most cyclic enol ethers under-
went exchange reaction and couplings with monosubsti-
tuted olefins bearing electron-withdrawing substituents
without problems, providing the expected 1,3-dienes in
good yields. Furthermore, silyl enol ethers derived from al- 2Ј-H), 7.50 (d, J ϭ 15.5 Hz, 1 H, 3-H) ppm.
Eur. J. Org. Chem. 2002, 3646Ϫ3658
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I. M. Lyapkalo, M. Webel, H.-U. Reißig
FULL PAPER
(E)-3-(Cyclopent-1-enyl)-1-{(1S,5R,7R)-10,10-dimethyl-3,3-dioxo- prepared by GP1, a mixture of nonaflate 2b (0.226 g, 0.53 mmol),
3λ6-thia-4-azatricyclo[5.2.1.01,5]dec-4-yl}propenone (4): This com-
pound was prepared by GP1, a mixture of nonaflate 2a (0.321 g,
nBu4NCl (0.139 g, 0.50 mmol), K2CO3 (0.142 g, 1.03 mmol),
Pd(OAc)2 (0.005 g, 0.02 mmol) and methyl acrylate (0.058 g,
0.88 mmol), KOAc (0.060 g, 0.61 mmol), K2CO3 (0.105 g, 0.67 mmol) in DMF (3 mL) being stirred at room temperature for
0.76 mmol), Pd(OAc)2 (0.008 g, 0.04 mmol) and (Ϫ)-N-propenoyl-
2,10-camphorsultam (0.237 g, 0.88 mmol) in DMF (2 mL) being
stirred at 75 °C for 6 h. The usual workup and CC (hexane/EtOAc,
6 h. The usual workup and CC (hexane/EtOAc, 10:1) furnished a
4:96 mixture of 7 and 8 (0.025 g, 24% overall yield) as a viscous
1
oil. Compound 7: H NMR (300 MHz, CDCl3): δ ϭ 2.37 (td, J ϭ
1:1) afforded
4
(0.239 g, 81% yield) as yellowish crystals,
8.0, 4.9 Hz, 2 H, 3Ј-H), 2.75 (t, J ϭ 8.0 Hz, 2 H, 4Ј-H), 3.79 (s,
m.p. 145Ϫ150 °C. [α]D ϭ Ϫ98 (c ϭ 0.42, CHCl3). The assignment 3 H, CO2Me), 6.26 (d, J ϭ 17.0 Hz, 1 H, 2-H), 6.46 (t, J ϭ 4.9 Hz,
of the NMR signals was made by COSY, NOESY, HSQC and
1 H, 2Ј-H), 7.62 (d, J ϭ 17.0 Hz, 1 H, 3-H) ppm; the signals of
HMBC. 1H NMR (500 MHz, CDCl3): δ ϭ 0.96 (s, 3 H, 12"-H), aromatic protons overlap with those of compound 8. 13C NMR
1.16 (s, 3 H, 11"-H), 1.35Ϫ1.39 (m, 1 H, 8"-H), 1.41Ϫ1.45 (m, 1 H, (75.5 MHz, CDCl3): δ ϭ 23.6, 27.8 (2 t, 2 CH2), 51.6 (q, CO2Me),
9"-H), 1.87Ϫ1.92 (m, 2 H, 8"-H, 9"-H), 1.95 (quint., J ϭ 7.3 Hz, 2 118.8, 124.1, 126.9, 127.5, 127.8, 133.2 (6 d, Ar, C-2, C-2Ј), 132.8,
H, 4Ј-H), 2.47 (br. t, J ϭ 7.3 Hz, 2 H, 3Ј-H), 2.42Ϫ2.57 (m, 2 H,
5Ј-H), AB-system (δA ϭ 3.42, δB ϭ 3.47, JAB ϭ 13.8 Hz, 2 H, 2"-
134.6, 136.6 (3 s, C-1Ј, C-8aЈ, C-4aЈ), 143.7 (d, C-3), 167.7 (s, C-1)
ppm. GC/MS data: tr ϭ 12.7 min. MS (EI, 70 eV): m/z (%) ϭ 214
H), ABMX-system (δX ϭ 3.93, δA ϭ 2.10, δB ϭ 2.08, δM ϭ 1.86, (25) [Mϩ], 181 (12), 153 (100), 76 (C6H4ϩ, 15). Compound 8: 1H
JAB ϭ 13.8, JAM ϭ 7.6, JBM ϭ 5.1, JAX ϭ 3.6 Hz, 4 H, 5"-H, 6"- NMR (300 MHz, CDCl3): δ ϭ 3.86 (s, 3 H, CO2Me), 6.53 (d, J ϭ
H, 7"-H), 6.23 (mc, 1 H, 2Ј-H), 6.41 (d, J ϭ 15.0 Hz, 1 H, 2-H),
15.8 Hz, 1 H, 2-H), 7.46Ϫ7.61 (m, 2 H, Ar), 7.75 (d, J ϭ 6.8 Hz,
7.57 (d, J ϭ 15.0 Hz, 1 H, 3-H) ppm. 13C NMR (125.8 MHz, 1 H, Ar), 7.86Ϫ7.91 (m, 2 H, Ar), 8.19 (d, J ϭ 8.6 Hz, 2 H, Ar),
CDCl3): δ ϭ 19.9 (q, C-12"), 20.8 (q, C-11"), 23.1 (t, C-4Ј), 26.5 (t, 8.54 (d, J ϭ 15.8 Hz, 1 H, 3-H) ppm; these data match those re-
C-8"), 30.7 (t, C-3Ј), 32.8 (t, C-9"), 33.6 (t, C-5Ј), 38.5 (t, C-6"), ported in ref.[27] 13C NMR (75.5 MHz, CDCl3): δ ϭ 51.8 (q,
44.7 (d, C-7"), 47.8, 48.4 (2 s, C-10ЈЈ, C-1"), 53.1 (t, C-2"), 65.1 (d,
C-5"), 117.4 (d, C-2), 135.3 (s, C-1Ј), 141.8 (d, C-3), 142.4 (d, C-
CO2Me), 120.4 (d, C-2), 131.4, 131.7, 133.7 (3 s, C-1Ј, C-8aЈ, C-
4aЈ), 123.4, 125.0, 125.4, 126.2, 126.9, 128.7, 130.5 (7 d, Ar), 141.9
2Ј), 164.8 (s, C-1) ppm. IR (film): ν˜ ϭ 3500Ϫ3190 cmϪ1 (NϪH), (d, C-3), 167.3 (s, C-1) ppm. GC/MS data: tr ϭ 14.2 min. MS (EI,
3100Ϫ3000 (ϭCϪH), 2960, 2890 (CϪH), 1675 (CϭO), 1615 70 eV): m/z (%) ϭ 212 (63) [Mϩ], 181 (65) [Mϩ Ϫ OCH3], 165 (12),
(CϭC), 1330 (CϪN). GC/MS-data: tr ϭ 20.5 min (275 °C). MS
153 (100) [Mϩ Ϫ C2H3O2], 141 (16), 128 (53) [C10H8ϩ], 115 (17)
(EI, 70 eV): m/z (%) ϭ 335 (14) [Mϩ], 121 (C8H9Oϩ, 100), 103 (10), [C9H7ϩ], 76 (22) [C6H4ϩ], 63 (10), 40 (14).
91 (22), 77 (20), 55 (16), 41 (10). C18H25NO3S (335.5): calcd. C
64.45, H 7.51, N 4.18, S 9.56; found C 64.41, H 7.64, N 4.13,
S 9.34.
Dimethyl 4-tert-Butylcyclohex-3-ene-1,2-dicarboxylate (10): A mix-
ture of 3,3-dimethylbuten-2-yl nonaflate (2c) (1.35 g, 3.53 mmol),
methyl acrylate (0.91 g, 10.6 mmol), lithium chloride (0.08 g,
1.89 mmol), triethylamine (0.46 g, 4.56 mmol) and Pd(OAc)2
(0.04 g, 0.18 mmol) in THF (3 mL) was heated with vigorous stir-
ring in a tightly closed flask at 58 °C for 60 h. After 13 h heating,
no starting nonaflate was any longer detectable in the reaction mix-
ture, the degree of conversion of methyl (E)-4-tert-butylpenta-2,4-
dienoate (9) into the cycloaddition product 10 (cis/trans ratio ϭ
1.7:1) being 50% (1H NMR). After 60 h heating, intermediate 9
had been completely consumed, resulting in cycloadduct 10 (cis/
trans ratio ϭ 1:4.6). Aqueous workup (50 mL hexane/15 mL satd.
aq. NaHCO3 and 15 mL water) followed by CC (gradient elution:
hexane/Et2O, 25:1 to 15:1 to 10:1 to 5:1) gave methyl (E)-6,6-di-
methylhept-2-en-4-ynoate (12,[28] 40 mg, 7% yield) as a yellowish
liquid, dimethyl 4-tert-butylcyclohex-3-ene-1,2-trans-dicarboxylate
(10b, 592 mg, 66%) as a yellowish oil (slowly crystallises upon keep-
ing in a freezer, m.p. 35Ϫ40 °C) and dimethyl 4-tert-butylcyclohex-
3-ene-1,2-cis-dicarboxylate (10a, 103 mg, 12%) as a yellowish oil.
Product 10b was distilled after CC (b.p. 150Ϫ155 °C/0.08 mbar, ku-
gelrohr) to obtain a correct microanalysis. Compound 12: 1H NMR
(500 MHz, CDCl3): δ ϭ 1.26 (s, 9 H, CMe3), 3.74 (s, 3 H, OMe),
6.13 (d, J ϭ 15.8 Hz, 1 H, 2-H), 6.77 (d, J ϭ 15.8 Hz, 1 H, 3-H)
ppm. 13C NMR (125.8 MHz, CDCl3): δ ϭ 28.3 (s, CMe3), 30.5 (q,
CMe3), 51.6 (q, OMe), 76.4 (s, C-4), 108.6 (s, C-5), 126.4 (d,
C-3*), 128.6 (d, C-2*), 175.4 (s, C-1) ppm; *the assignment of these
signals is given as described for closely related ethyl ester.[29] Com-
4-(Cyclopent-1-enyl)but-3-enyl Acetate (5) and (Z)-4-(Cyclopent-1-
enyl)but-2-enyl Acetate (6): These compounds were prepared by
GP1, a mixture of nonaflate 2a (0.366 g, 1.00 mmol), KOAc
(0.068 g, 0.69 mmol), K2CO3 (0.120 g, 0.87 mmol), Pd(OAc)2
(0.009 g, 0.04 mmol) and but-3-en-1-yl acetate (1.25 g, 1.10 mmol)
in DMF (3 mL) being stirred at 60 °C for 7 h. The usual workup,
CC (hexane/EtOAc, 10:1) and kugelrohr distillation furnished a
68:7:25 mixture of (E)-5, (Z)-5 and 6 (0.165 g, 91% overall yield)
1
as a colourless oil. (E)-5: H NMR (300 MHz, CDCl3): δ ϭ 2.05
(s, 3 H, Me), 1.52Ϫ1.96, 2.36Ϫ2.49 (2 m, 5 H, 3 H, 4 CH2), 4.11
(t, J ϭ 6.8 Hz, 2 H, 1-H), 5.47 (dt, J ϭ 15.5, 6.9 Hz, 1 H, 3-H),
5.64 (mc, 1 H, 2Ј-H), 6.35 (d, J ϭ 15.5 Hz, 1 H, 4-H) ppm. 13C
NMR (75.5 MHz, CDCl3): δ ϭ 21.0 (q, Me), 23.0, 31.3, 32.1, 32.7
(4 t, 4 CH2), 63.9 (t, C-1), 125.3 (d, C-2Ј), 129.5, 129.6 (2 d, C-4,
C-3), 142.3 (s, C-1Ј), 171.1 (s, CϭO) ppm. GC/MS-data: tr
ϭ
22.7 min. MS (EI, 70 eV): m/z (%) ϭ 180 (Ͻ1) [Mϩ], 120 (66) [Mϩ
Ϫ AcOH], 105 (41), 91 (100), 79 (40), 43 (72). The following signals
can be assigned to compound (Z)-5: 1H NMR (300 MHz, CDCl3):
δ ϭ 4.20 (t, J ϭ 5.8 Hz, 2 H, 1-H), 5.71 (dt*, J ϭ 10.0, 5.8 Hz, 1
H, 3-H), 5.72 (mc, 1 H, 2Ј-H), 6.12 (d, J ϭ 10.0 Hz, 1 H, 4-H)
ppm; *the signal overlaps with the 2Ј-H signal. GC/MS data: tr ϭ
22.6 min. MS (EI, 70 eV): m/z (%) ϭ 180 (Ͻ1) [Mϩ], 120 (46) [Mϩ
Ϫ AcOH], 105 (38), 91 (100), 79 (38), 43 (65). The following signals
can be assigned to compound 6: 1H NMR (300 MHz, CDCl3): δ ϭ
2.07 (s, 3 H, Me), 2.81 (d, J ϭ 6.3 Hz, 1 H, 4-H), 4.53 (d, J ϭ
6.3 Hz, 1 H, 1-H), 4.97 (br. d, J ϭ 8.7 Hz, 1 H, 2-H), 5.36 (mc, 1
H, 2Ј-H), 5.60 (br. d, J ϭ 8.7 Hz, 1 H, 3-H) ppm. GC/MS data:
tr ϭ 22.1 min. MS (EI, 70 eV): m/z (%) ϭ 180 (4) [Mϩ], 120 (52)
[Mϩ Ϫ AcOH], 105 (68), 91 (100), 79 (36), 43 (88). 5/6 Mixture:
IR (film): ν˜ ϭ 3150Ϫ3000 cmϪ1 (ϭCϪH), 2960Ϫ2850 (CϪH),
1740 (CϭO), 1615 (CϭC), 1240 (CϪOϪC).
1
pound 10b: H NMR (270 MHz, CDCl3): δ ϭ 1.03 (s, 9 H, CMe3),
1.54Ϫ1.70, 1.98Ϫ2.24 (2 m, 1 H, 3 H, 2 CH2), 2.86 (ddd, J ϭ 12.0,
9.6, 3.0 Hz, 1 H, 6-H), 3.53 (d*, J ϭ 9.6 Hz, 1 H, 1-H), 3.71 (s, 3
H, CO2Me), 3.72 (s, 3 H, CO2Me), 5.47Ϫ5.50 (m, 1 H, 2-H) ppm; *
further splitting due to the multiple couplings. 13C NMR
(67.9 MHz, CDCl3): δ ϭ 23.4, 25.6 (2 t, C-4, C-5), 28.7 (q, CMe3),
35.4 (s, CMe3), 41.3, 44.2 (2 d, C-1, C-6), 51.8, 52.0 (2 q, 2 CO2Me),
Methyl (E)-3-(3,4-Dihydronaphthalen-1-yl)propenoate (7) and 114.0 (d, C-2), 147.6 (s, C-3), 174.1, 175.4 (2 s, 2 CO2Me) ppm. IR
Methyl (E)-3-(1-Naphthyl)propenoate (8): These compounds were
(film): ν˜ ϭ 3060 cmϪ1 (ϭCϪH), 2965, 2950, 2925 (CϪH), 1720
3652
Eur. J. Org. Chem. 2002, 3646Ϫ3658

One-Pot Transformation of Silyl Enol Ethers into 1,3-Dienes
FULL PAPER
(br., CϭO), 1685 (CϭC). C14H22O4 (254.3): calcd. C 66.12, H 8.72; 22.6, 28.7, 29.0, 29.1, 31.7, 33.0 (6 t, CH2), 51.4 (q, CO2Me), 118.6
found C 65.97, H 8.67. Compound 10a: 1H NMR (270 MHz, (d, C-2), 128.3 (d, C-4), 144.0 (d, C-5), 145.5 (d, C-3), 167.7 (s, C-
CDCl3): δ ϭ 1.04 (s, 9 H, CMe3), 1.96Ϫ2.26 (m, 4 H, 2 CH2), 2.66 1) ppm. The following signals can be assigned to compound (E,Z)-
(ddd, J ϭ 10.4, 5.6, 3.5 Hz, 1 H, 6-H), 3.47Ϫ3.52 (m, 1 H, 1-H), 14: 1H NMR (500 MHz, CDCl3): δ ϭ 2.23Ϫ2.31 (m, 2 H, 6-H),
3.68 (s, 6 H, 2 CO2Me), 5.60 (d*, J ϭ 4.8 Hz, 1 H, 2-H) ppm;
*further splitting due to the multiple couplings. 13C NMR
(67.9 MHz, CDCl3): δ ϭ 22.2, 23.9 (2 t, C-4, C-5), 28.9 (q, CMe3),
35.5 (s, CMe3), 40.9, 42.4 (2 d, C-1, C-6), 51.6, 51.7 (2 q, 2 CO2Me),
114.0 (d, C-2), 148.7 (s, C-3), 173.1, 174.0 (2 s, 2 CO2Me) ppm.
3.74 (s, 3 H, CO2Me), 5.85 (d, J ϭ 14.9 Hz, 1 H, 2-H), 7.55Ϫ7.66
(m, 1 H, 3-H) ppm.
Methyl (E)-5-Methylhexa-2,4-dienoate (15): This compound was
prepared by GP1, a mixture of nonaflate 2e (0.845 g, 2.50 mmol),
nBu4NCl (0.695 g, 2.50 mmol), K2CO3 (0.690 g, 5.00 mmol),
Pd(OAc)2 (0.022 g, 0.10 mmol) and methyl acrylate (0.645 g,
7.50 mmol) in DMF (15 mL) being stirred at room temperature for
6 h. The usual workup and CC (hexane/EtOAc, 10:1) furnished
15[33] (0.275 g, 78% yield, E/Z Ͼ 97:3) as a yellow oil. Compound
MS (EI, 80 eV): m/z (%)
ϭ
254 (14) [Mϩ], 222 (21)
[Mϩ Ϫ CH3OH], 195 (32) [Mϩ Ϫ CO2CH3], 194 (100)
[Mϩ Ϫ HCO2CH3], 179 (34) [Mϩ Ϫ HCO2CH3 Ϫ CH3], 138 (19)
[Mϩ Ϫ CO2CH3 Ϫ tBu], 135 (20) [Mϩ Ϫ HCO2CH3 Ϫ CO2CH3],
119 (14) [tBuC6H6ϩ Ϫ CH4], 57 (29) [tBuϩ].
1
(E)-15: H NMR (300 MHz, CDCl3): δ ϭ 1.87, 1.89 (2 br. s, 3 H
each, 2 Me), 3.74 (s, 3 H, CO2Me), 5.75 (br. d, J ϭ 15.2 Hz, 1 H,
2-H), 5.99 (dd, J ϭ 11.6, 0.6 Hz, 1 H, 4-H), 7.56 (dd, J ϭ 15.2,
11.6 Hz, 1 H, 3-H) ppm. 13C NMR (75.5 MHz, CDCl3): δ ϭ 18.9,
26.5 (2 q, 2 Me), 51.4 (q, CO2Me), 118.1 (d, C-4), 123.7 (d, C-2),
141.2 (d, C-3), 146.5 (s, C-5), 168.1 (s, C-1) ppm. The following
signals can be assigned to (Z)-15: 1H NMR (300 MHz, CDCl3):
δ ϭ 1.86, 1.92 (2 s, 3 H each, 2 Me), 3.72 (s, 3 H, CO2Me), 5.56
(br. d, J ϭ 11.6 Hz, 1 H, 2-H), 6.87 (dd, J ϭ 11.7, 11.6 Hz, 1 H,
3-H), 7.18 (dd, J ϭ 11.7, 1.2 Hz, 1 H, 4-H) ppm.
Epimerisation of Dimethyl 4-tert-Butylcyclohex-3-ene-1,2-cis-di-
carboxylate (10): DBU (19 mg) was added to the solution of 10a
(21 mg) in C6D6 (0.55 mL) in the NMR tube, and the sample was
kept at room temp. for 15 h. The subsequent 1H NMR spectrum
indicated a 1:7 cis/trans ratio. In the control experiment in the ab-
sence of DBU, no changes were observed after heating at 60 °C for
the same period of time.
Dimethyl 4-(tert-Butyl)phthalate (13): Chlorobenzene (10 mL) was
added to a mixture of dimethyl 4-tert-butylcyclohex-3-ene-1,2-
trans-dicarboxylate (10b, 127 mg, 0.50 mmol) and 2,3-dichloro-5,6-
dicyanobenzoquinone (DDQ, 341 mg, 1.50 mmol), and the re-
sulting mixture was heated at reflux for 24 h. After this had been
cooled to ambient temperature, the solvent was removed under va-
cuum (0.05 mbar), and the residue was treated with CCl4 (15 mL)
and filtered. The precipitate was carefully washed with CCl4 (3 ϫ
5 mL), and the mother solution was evaporated under vacuum. 1H
NMR monitoring of the crude residue showed Ն 98% conversion
of the starting material and 3Ϫ4 mol % admixture of dimethyl 5-
tert-butylbenzene-1,3-dicarboxylate[30] with the main product, di-
methyl 4-tert-butylbenzene-1,2-dicarboxylate (13). The residue was
subjected to CC (gradient elution: hexane/Et2O, 5:1 to 3:1) to give
spectroscopically and analytically pure 13[31] (111 mg, 89% yield)
as yellowish oil. 1H NMR (270 MHz, CDCl3): δ ϭ 1.34 (s, 9 H,
CMe3), 3.89 (s, 3 H, CO2Me), 3.92 (s, 3 H, CO2Me), 7.55 (dd, J ϭ
8.2, 2.0 Hz, 1 H, 5-H), 7.68 (dd, J ϭ 2.0, 0.4 Hz, 1 H, 3-H), 7.71
(dd, J ϭ 8.2, 0.4 Hz, 1 H, 6-H) ppm. 13C NMR (67.9 MHz,
CDCl3): δ ϭ 30.9 (q, CMe3), 35.0 (s, CMe3), 52.4, 52.5 (2 q, 2
CO2Me), 125.6, 127.8, 129.0 (3 d, C-3, C-5, C-6), 128.4, 132.4 (2 s,
C-1, C-2), 155.1 (s, C-4), 167.7, 168.8 (2 s, 2 CO2Me) ppm. MS
(EI, 80 eV): m/z (%) ϭ 250 (20) [Mϩ], 235 (100) [Mϩ Ϫ CH3], 219
(23) [Mϩ Ϫ CH3O]. IR (film): ν˜ ϭ 2955, 2905, 2870 cmϪ1 (ϭCϪH,
CϪH), 1730 (CϭO). C14H18O4 (250.3): calcd. C 67.18, H 7.25;
found C 66.81, H 7.16.
One-pot Heck-coupling Procedure Starting from Silyl Enol Ethers
1: General Procedure 2 (GP2): The corresponding nonaflate 2 was
generated by treatment of silyl enol ether 1 with nonafluorobutyl-
sulfonyl fluoride (NfF) in the presence of nBu4NF (method D) or
dibenzo-18-crown-6 (db-18-c-6)/KF (method E) at room temper-
ature (reaction time 16 h unless otherwise noted) as described
earlier.[5]Ϫ Base, additive, olefin and Pd(OAc)2 (4Ϫ8 mol %) were
added to this mixture according to GP1, and the resulting solution
was stirred under the conditions indicated in the individual experi-
ments. After aqueous workup and extraction with EtOAc or n-
pentane the pure product was isolated by CC or kugelrohr distilla-
tion.
Methyl (E)-3-(Cyclopent-1-enyl)propenoate (3): Nonaflation of silyl
enol ether 1a (0.390 g, 2.50 mmol) with NfF (0.906 g, 3.00 mmol)
was performed according to GP2, with nBu4NF (0.45 mmol) in
THF (0.45 mL). After addition of nBu4NCl (0.862 g, 6.25 mmol),
K2CO3 (0.862 g, 6.25 mmol), Pd(OAc)2 (0.042 g, 0.19 mmol),
methyl acrylate (0.645 g, 7.50 mmol) and DMF (15 mL) the mix-
ture was stirred at 25 °C for 6 h. Isolation and purification as de-
scribed above provided product 3[26] (0.286 g, 75% yield).
(E)-3-(Cyclopent-1-enyl)-1-{(1S,5R,7R)-10,10-dimethyl-3,3-dioxo-
3λ6-thia-4-azatricyclo[5.2.1.01,5]dec-4-yl}propenone (4): Nonaflation
of 1a (0.109 g, 0.70 mmol) with NfF (0.254 g, 0.84 mmol) was per-
formed according to GP2, with nBu4NF (0.13 mmol) in THF
(0.13 mL). After addition of KOAc (0.048 g, 0.49 mmol), K2CO3
(0.084 g, 0.61 mmol), Pd(OAc)2 (0.006 g, 0.03 mmol), (Ϫ)-N-pro-
penoyl-2,10-camphorsultam (0.188 g, 0.70 mmol) and DMF
(2 mL), the mixture was stirred at 75 °C for 6 h. Isolation and puri-
fication as described above provided 4 (0.116 g, 49% yield).
Methyl (E,E)-Dodeca-2,4-dienoate (14): This compound was pre-
pared by GP1, a mixture of nonaflate 2d (0.300 g, 0.71 mmol),
nBu4NCl (0.262 g, 0.94 mmol), K2CO3 (0.201 g, 1.45 mmol),
Pd(OAc)2 (0.007 g, 0.03 mmol) and methyl acrylate (0.092 g,
1.07 mmol) in DMF (15 mL) being stirred at room temperature for
6 h. The usual workup and CC (hexane/EtOAc, 10:1) provided
14[32] (0.127 g, 85% yield, E,E/E,Z ϭ 96:4) as a yellow oil. An as-
signment of the NMR signals was made by COSY and HSQC.
(E)-2-(Cyclopent-1-enyl)styrene (16): Nonaflation of 1a (0.780 g,
5.00 mmol) with NfF (3.02 g, 10.0 mmol) was performed with
Compound (E,E)-14: 1H NMR (500 MHz, CDCl3): δ ϭ 0.88 (t, J ϭ nBu4NF (0.90 mmol) in THF (0.9 mL) according to GP2. After
6.5 Hz, 3 H, Me), 1.24Ϫ1.29 (m, 8 H, CH2), 1.40 (quint., J ϭ addition of KOAc (0.343 g, 3.50 mmol), K2CO3 (0.602 g,
7.0 Hz, 2 H, 7-H), 2.13 (q, J ϭ 7.0 Hz, 2 H, 6-H), 3.72 (s, 3 H,
CO2Me), 5.76 (d, J ϭ 15.4 Hz, 1 H, 2-H), 6.10 (dt, J ϭ 13.3, 5.25 mmol) and DMF (6 mL), the mixture was stirred at 85 °C for
7.0 Hz, 1 H, 5-H), 6.14* (dd, J ϭ 13.3, 10.0 Hz, 1 H, 4-H), 7.25 6 h followed by the usual workup and CC (hexane/EtOAc, 10:1) to
4.36 mmol), Pd(OAc)2 (0.039 g, 0.17 mmol), styrene (0.546 g,
(dd, J ϭ 15.4, 10.0 Hz, 1 H, 3-H) ppm; *the signal overlaps with afford 16 (0.522 g, 61% yield) as a yellow solid, m.p. 35Ϫ44 °C
the 5-H signal. 13C NMR (125.8 MHz, CDCl3): δ ϭ 14.1 (q, Me), (ref.[34] 36Ϫ40 °C). 1H NMR (200 MHz, CDCl3): δ ϭ 1.97 (quint.,
Eur. J. Org. Chem. 2002, 3646Ϫ3658
3653

I. M. Lyapkalo, M. Webel, H.-U. Reißig
J ϭ 7.5 Hz, 2 H, CH2), 2.45Ϫ2.63 (m, 4 H, 2 CH2), 5.86 (mc, 1 H, 5.25 mmol) and DMF (6 mL), the mixture was stirred at 75 °C for
FULL PAPER
2Ј-H), 6.41, 7.01 (2 d, J ϭ 16.0 Hz, 1 H each, 1-H, 2-H), 7.15Ϫ7.45
4 h, followed by the usual workup and CC (hexane/EtOAc, 20:1),
(m, 5 H, Ph) ppm. 13C NMR (50.3 MHz, CDCl3): δ ϭ 23.2, 31.2, to afford 19[34] (0.569 g, 56% yield) as a yellowish solid (m.p. ca.
33.0 (3 t, 3 CH2), 125.8, 128.7, 132.0 (3 d, C-2Ј, C-2, C-1), 126.2, 25 °C). 1H NMR (200 MHz, CDCl3): δ ϭ 1.55Ϫ1.81, 2.15Ϫ2.38
127.1, 128.5, 137.8 (3 d, s, Ph), 142.8 (s, C-1Ј) ppm.
(2 m, 4 H each, 4 CH2), 5.90 (t, J ϭ 4.0 Hz, 1 H, 2Ј-H), 6.41, 6.95
(2 d, J ϭ 16.0 Hz, 1 H each, 2-H, 1-H), 7.10Ϫ7.45 (m, 5 H, Ph)
ppm. 13C NMR (50.3 MHz, CDCl3): δ ϭ 22.5, 22.55, 24.5, 26.1 (4
t, CH2), 124.6, 130.8, 132.6, (3 d, C-1, C-2, C-2Ј), 126.1, 126.8,
128.5, 138.0 (s, 3 d, Ph), 135.8 (s, C-1Ј) ppm.
2-(Cyclopent-1-enyl)ethenyl Acetate (17): Nonaflation of 1a
(0.390 g, 2.50 mmol) with NfF (0.906 g, 3.00 mmol) was performed
with nBu4NF (0.45 mmol) in THF (0.45 mL) according to GP2.
After addition of KOAc (0.301 g, 3.07 mmol), K2CO3 (0.172 g,
1.25 mmol), Pd(OAc)2 (0.020 g, 0.09 mmol), vinyl acetate (1.03 g,
12.0 mmol) and DMF (8 mL), the mixture was stirred at 60 °C for
6 h, followed by the usual workup and CC (hexane/EtOAc, 10:1)
to afford 17[35] (0.130 g, 34% yield, E:Z ϭ 77:23) as a colourless
oil. (E)-17: 1H NMR (300 MHz, CDCl3): δ ϭ 1.94 (quint., J ϭ
7.0 Hz, 2 H, CH2), 2.13 (s, 3 H, Me), 2.38 (br. t, J ϭ 7.0 Hz, 4 H,
2 CH2), 5.70 (mc, 1 H, 2Ј-H), 6.24, 7.24 (2 d, J ϭ 12.6 Hz, 1 H
each, 2-H, 1-H) ppm. 13C NMR (75.5 MHz, CDCl3): δ ϭ 20.7 (q,
Me), 23.2, 31.6, 32.7 (3 t, CH2), 109.5 (d, C-2), 112.6 (d, C-2Ј),
131.2 (d, C-1), 136.2 (s, C-1Ј), 168.1 (s, CϭO) ppm. The following
signals can be assigned to (Z)-17: 1H NMR (300 MHz, CDCl3):
δ ϭ 2.15 (s, 3 H, Me), 2.65, 2.66 (2 t, J ϭ 7.5 Hz and 7.7 Hz, 2 H
each, CH2), 5.51 (d, J ϭ 6.9 Hz, 1 H, 2-H), 5.79 (mc, 1 H, 2Ј-H),
6.96 (d, J ϭ 6.9 Hz, 1 H, 1-H) ppm. 13C NMR (75.5 MHz, CDCl3):
δ ϭ 20.8 (q, Me), 23.7, 32.2, 34.4 (3 t, 3 CH2), 132.2 (d, C-2), 132.5
(d, C-2Ј), 136.2 (d, C-1), 138.1 (s, C-1Ј), 168.1 (s, CϭO) ppm.
Methyl (E)-3-(4-tert-Butylcyclohex-1-enyl)propenoate (20): Nona-
flation of silyl enol ether 1g (0.582 g, 2.57 mmol) with NfF (0.906 g,
3.00 mmol) was performed with nBu4NF (0.45 mmol) in THF
(0.45 mL) according to GP2. After addition of KOAc (0.172 g,
1.75 mmol), K2CO3 (0.301 g, 2.18 mmol), Pd(OAc)2 (0.020 g,
0.09 mmol), methyl acrylate (0.230 g, 2.67 mmol) and DMF
(5 mL), the mixture was stirred at 80 °C for 7 h, followed by the
usual workup and CC (hexane/EtOAc, 5:1), to give 20[6,17] (0.398 g,
70% yield) as a colourless crystalline solid, m.p. 34Ϫ36 °C (ref.[17]
37.5Ϫ39 °C).
(E)-2-(4-tert-Butylcyclohex-1-enyl)ethen-1-yl Phenyl Sulfone (21)
and (E)-2-(4-tert-Butylcyclohex-2-en-1-ylidene)ethyl Phenyl Sulfone
(22): Nonaflation of silyl enol ether 1g (0.227 g, 1.00 mmol) with
NfF (0.395 g, 1.30 mmol) was performed in DMF (1 mL) with KF
(0.060 g, 1.03 mmol) and dibenzo-18-crown-6 (0.054 g, 0.15 mmol)
at 25 °C for 60 h according to GP2. LiCl (0.042 g, 1.00 mmol),
Et3N (0.132 g, 1.30 mmol), phenyl vinyl sulfone (0.219 g,
1.30 mmol) and Pd(OAc)2 (0.011 g, 0.05 mmol) were then added,
and the mixture was stirred at 100 °C for 18 h (complete conversion
of the nonaflate, 6:1 ratio of products according to 1H NMR of
the reaction mixture), followed by the usual workup (hexane/Et2O,
1:1) and CC (gradient elution: hexane/Et2O, 25:1 to 15:1 to 5:1),
to provide 21 (0.222 g, 73% yield) as colourless crystals
(m.p. 127Ϫ129 °C) and 22 (0.038 g, 13% yield) as a colourless, crys-
Methyl (E)-3-(Cyclohex-1-enyl)propenoate (18)
Starting from 1-(Trimethylsiloxy)cyclohexene (1f): Nonaflation of
silyl enol ether 1f (0.383 g, 2.25 mmol) with NfF (0.906 g,
3.00 mmol) was performed with nBu4NF (0.45 mmol) in THF
(0.45 mL) according to GP2. After addition of nBu4NCl (0.655 g,
2.36 mmol), K2CO3 (0.670 g, 4.85 mmol), Pd(OAc)2 (0.022 g,
0.10 mmol), methyl acrylate (0.276 g, 3.21 mmol) and DMF
(8 mL), the mixture was stirred at 25 °C for 6 h, followed by the
usual workup and CC (hexane/EtOAc, 10:1), to furnish 18[26]
(0.236 g, 63% yield) as a yellowish oil.
1
talline solid (m.p. 53Ϫ59 °C). Compound 21: H NMR (270 MHz,
CDCl3): δ ϭ 0.87 (s, 9 H, CMe3), 1.07Ϫ1.33, 1.84Ϫ2.10, 2.13Ϫ2.35
(3 m, 2 H, 3 H, 2 H, 3Ј-H to 6Ј-H), 6.19 (d, J ϭ 15.1 Hz, 1 H, 1-
H), 6.28Ϫ6.33 (m, 1 H, 2Ј-H), 7.29 (d, J ϭ 15.1 Hz, 1 H, 2-H),
7.49Ϫ7.63, 7.87Ϫ7.92 (2 m, 3 H, 2 H, Ph) ppm. 13C NMR
(67.9 MHz, CDCl3): δ ϭ 23.1, 25.4, 28.2 (3 t, C-3Ј, C-5Ј, C-6Ј),
27.0 (q, CMe3), 32.1 (s, CMe3), 43.5 (d, C-4Ј), 123.7, 133.0, 142.0,
145.4 (4 d, C-1, C-2, C-2Ј, Cp), 127.3, 129.1 (2 d, Co, Cm), 133.2,
141.3 (2 s, C-1Ј, CPhSO2) ppm. MS (EI, 80 eV): m/z (%) ϭ 306 (7)
[Mϩ ϩ 2], 305 (21) [Mϩ ϩ 1], 304 (100) [Mϩ], 289 (1) [Mϩ Ϫ
Me], 248 (43) [Mϩ Ϫ CH2ϭC(CH3)2], 247 (56) [Mϩ Ϫ tBu], 234
(6) [Mϩ Ϫ CH2ϭC(CH3)2 Ϫ CH2], 233 (5) [Mϩ Ϫ tBu Ϫ CH2], 221
(11) [Mϩ Ϫ tBu Ϫ C2H2], 163 (11) [Mϩ Ϫ PhSO2], 162 (4) [Mϩ Ϫ
PhSO2H], 147 (9) [Mϩ Ϫ PhSO2 Ϫ CH4], 143 (5) [C11H11ϩ] or
[PhS(OH)2ϩ], 125 (14) [PhSOϩ], 121 (5) [Mϩ Ϫ PhSO2 Ϫ CH2ϭ
CHCH3], 119 (11) [C9H11ϩ], 107 (19) [Mϩ Ϫ PhSO2 Ϫ CH2ϭ
C(CH3)2], 106 (15) [Mϩ Ϫ PhSO2 Ϫ tBu], 105 (25) [C8H9ϩ], 93 (14)
[C7H9ϩ], 91 (28) [PhCH2ϩ], 79 (27) [C6H7ϩ], 77 (30) [Phϩ], 57 (67)
[tBuϩ], 41 (35) [CH2ϭCHCH2ϩ]. IR (film): ν˜ ϭ 3070, 2960, 2865,
2845 cmϪ1 (ϭCϪH, CϪH), 1635 (CϭC), 1315, 1150 (SO2).
C18H24O2S (304.45): calcd. C 71.01, H 7.95; found C 71.03, H 7.93.
Compound 22: 1H NMR (270 MHz, CDCl3): δ ϭ 0.84 (s, 9 H,
CMe3), 0.84Ϫ1.00 (m, 1 H, 5Ј-Ha), 1.53Ϫ1.70 (m, 2 H, 5Ј-He, 6Ј-
Ha), 1.81Ϫ1.90 (m, 1 H, 4Ј-Ha), 2.14Ϫ2.25 (m, 1 H, 6Ј-He), 3.90
(d, J ϭ 8.3 Hz, 2 H, 1-H), 5.20 (br. t, J ϭ 8.3 Hz, 1 H, 2-H), 5.85
Starting from 1-(tert-Butyldimethylsiloxy)cyclohexene (1fЈ): Neat
1-(tert-butyldimethylsiloxy)cyclohexene (1fЈ) (0.425 g, 2.00 mmol)
was added dropwise to a suspension of potassium ethanolate
(0.178 g, 2.00 mmol, 95% assay) in THF (3 mL), and the resulting
mixture was stirred at room temperature for 24 h before cooling to
Ϫ78 °C. Neat NfF (0.725 g, 2.40 mmol) was added, and the reac-
tion mixture was allowed to warm to room temperature and stirred
for 17 h. The 1H NMR spectrum of the reaction mixture indicated
complete conversion of the silyl enol ether into the nonaflate. Addi-
tion of LiCl (0.084 g, 2.00 mmol), methyl acrylate (0.224 g,
2.60 mmol), DMF (1 mL), Et3N (0.263 g, 2.60 mmol) and
Pd(OAc)2 (0.022 g, 0.10 mmol) and stirring at 72 °C for 4 h fur-
nished, after the usual workup (hexane) and CC (hexane/Et2O,
10:1), pure methyl (E)-3-(cyclohex-1-enyl)propenoate (18, 0.225 g,
68% yield) as a yellowish oil. 1H NMR (270 MHz, CDCl3): δ ϭ
1.57Ϫ1.74, 2.11Ϫ2.26 (2 m, 4 H, 4 H, 4 CH2), 3.75 (s, 3 H,
CO2Me), 5.77 (dd, J ϭ 15.8, 0.7 Hz, 1 H, 2-H), 6.16 (br. t, J ϭ
4.1 Hz, 1 H, 2Ј-H), 7.27 (br. d, J ϭ 15.8 Hz, 1 H, 3-H) ppm. 13C
NMR (67.9 MHz, CDCl3): δ ϭ 21.95, 21.98, 24.0, 26.4 (4 t, 4 CH2),
51.3 (q, CO2Me), 114.1 (d, C-2), 134.8 (s, C-1Ј), 138.8 (d, C-2Ј),
148.3 (d, C-3), 168.0 (s, C-1) ppm.
(E)-(2-Cyclohex-1-enyl)styrene (19): Nonaflation of 1f (0.852 g,
5.00 mmol) with NfF (3.02 g, 10.0 mmol) was performed with (br. d, J ϭ 10.2 Hz, 1 H, 3Ј-H), 6.06 (dd, J ϭ 10.2, 2.7 Hz, 1 H,
nBu4NF (1.70 mmol) in THF (1.7 mL) according to GP2. After 2Ј-H), 7.50Ϫ7.57, 7.61Ϫ7.68, 7.85Ϫ7.89 (3 m, 2 H, 1 H, 2 H, Ph)
addition of KOAc (0.343 g, 3.50 mmol), K2CO3 (0.602 g, ppm. 13C NMR (67.9 MHz, CDCl3): δ ϭ 23.4, 25.0 (2 t, C-5Ј, C-
4.36 mmol), Pd(OAc)2 (0.039 g, 0.17 mmol), styrene (0.546 g, 6Ј), 27.2 (q, CMe3), 32.6 (s, CMe3), 46.3 (d, C-4Ј), 55.9 (t, C-1),
3654
Eur. J. Org. Chem. 2002, 3646Ϫ3658

One-Pot Transformation of Silyl Enol Ethers into 1,3-Dienes
FULL PAPER
110.3 (d, C-2), 128.5, 128.9 (2 d, Co, Cm), 130.0, 133.5, 134.1 (3 d, Methyl 3-(Cyclohept-1-enyl)-2-methylpropenoate (26) and Methyl 2-
C-2Ј, C-3Ј, Cp), 138.7, 143.8 (2 s, C-1Ј, CPhSO2) ppm. MS (EI, (Cyclohept-1-enylmethyl)acrylate (27): Nonaflation of 1h (0.920 g,
80 eV): m/z (%) ϭ 304 (6) [Mϩ], 247 (1) [Mϩ Ϫ tBu], 163 (100) 5.00 mmol) with NfF (3.02 g, 10.0 mmol) was performed with
[Mϩ Ϫ PhSO2], 148 (1) [Mϩ Ϫ PhSO2 Ϫ CH3], 147 (4) [Mϩ Ϫ nBu4NF (0.90 mmol) in THF (0.9 mL) according to GP2. After
PhSO2 Ϫ CH4], 143 (5) [C11H11ϩ] or [PhS(OH)2ϩ], 141 (1) addition of KOAc (0.343 g, 3.50 mmol), K2CO3 (0.602 g,
[PhSO2ϩ], 133 (2) [Mϩ Ϫ PhSO2 Ϫ 2 CH3], 125 (2) [PhSOϩ], 121 4.36 mmol), Pd(OAc)2 (0.039 g, 0.17 mmol), methyl methacrylate
(2) [Mϩ Ϫ PhSO2 Ϫ CH2ϭCHCH3], 107 (33) [Mϩ Ϫ PhSO2 Ϫ
(0.525 g, 5.25 mmol) and DMF (6 mL), the mixture was stirred at
CH2ϭC(CH3)2], 106 (23) [Mϩ Ϫ PhSO2 Ϫ tBu], 105 (12) [C8H9ϩ], 85 °C for 6 h, followed by the usual workup and CC (hexane/
93 (12) [C7H9ϩ], 91 (12) [PhCH2ϩ], 77 (Phϩ, 9), 57 (31) [tBuϩ]. IR
(film): ν˜ ϭ 3060, 3015, 2950, 2870, 2825 cmϪ1 (ϭCϪH, CϪH),
EtOAc, 10:1), to provide a 52:9:39 mixture of (E)-26, (Z)-26 and
27 (0.495 g, 51% overall yield). Compound (E)-26: 1H NMR
1640 (CϭC), 1305, 1145 (SO2). C18H24O2S (304.45): calcd. C 71.01, (200 MHz, CDCl3): δ ϭ 1.96 (d, J ϭ 1.5 Hz, 3 H, 2-Me),
H 7.95; found C 71.14, H 7.93.
1.44Ϫ1.59, 1.67Ϫ1.79, 2.03Ϫ2.34 (3 m, 4 H, 2 H, 4 H, 5 CH2),
3.75 (s, 3 H, OMe), 5.53 (q, J ϭ 1.5 Hz, 1 H, 3-H), 5.60 (t, J ϭ
6.5 Hz, 1 H, 2Ј-H) ppm. 13C NMR (50.3 MHz, CDCl3): δ ϭ 14.1
(q, 2-Me), 26.4, 26.7, 28.9, 32.3, 32.5 (5 t, 5 CH2), 51.75 (q, OMe),
136.9, 139.1, 141.1, 143.3 (d, 2 s, d, C-2Ј, C-1Ј, C-3, C-2), 169.6 (s,
C-1) ppm. IR (gas phase): ν˜ ϭ 3000 cmϪ1 (ϭCϪH), 2930 (CϪH),
2855 (CH2), 1740 (CϭO), 1630 (CϭC), 1145 (CϪOϪC). The fol-
Methyl (E)-3-(Cyclohept-1-enyl)propenoate (23): Nonaflation of si-
lyl enol ether 1h (0.920 g, 5.00 mmol) with NfF (3.02 g, 10.0 mmol)
was performed with nBu4NF (0.90 mmol) in THF (0.9 mL) accord-
ing to GP2. After addition of KOAc (0.343 g, 3.50 mmol), K2CO3
(0.602 g, 4.36 mmol), Pd(OAc)2 (0.039 g, 0.17 mmol), methyl acryl-
ate (0.452 g, 5.25 mmol) and DMF (6 mL), the mixture was stirred
at 85 °C for 6 h, followed by the usual workup and CC (hexane/
EtOAc, 20:1), to provide 23[36] (0.580 g, 64% yield) as a yellow oil.
1
lowing signals can be assigned to the compound (Z)-26: H NMR
(200 MHz, CDCl3): δ ϭ 3.72 (s, 3 H, OMe), 6.17 (t, J ϭ 6.5 Hz, 1
H, 2Ј-H) ppm. 13C NMR (50.3 MHz, CDCl3): δ ϭ 13.9 (q, 2-Me),
26.45, 28.1, 32.0, 33.9, 36.8 (5 t, 5 CH2), 51.7 (q, OMe), 127.2,
136.6, 141.0, 144.4 (s, d, s, d, C-2Ј, C-1Ј, C-3, C-2) ppm. IR (gas
phase): ν˜ ϭ 3060 cmϪ1 (ϭCϪH), 2935 (CϪH), 2855 (CH2), 1740
(CϭO), 1650 (CϭC), 1250 (CϪOϪC). Compound 27: 1H NMR
(200 MHz, CDCl3): δ ϭ 1.44Ϫ1.59, 1.67Ϫ1.79, 2.03Ϫ2.34 (3 m, 4
H, 2 H, 4 H, 5 CH2), 2.98 (br. s, 2 H, 2-CH2), 3.75 (s, 3 H, OMe),
6.00 (t, J ϭ 6.5 Hz, 1-H, 2Ј-H), 6.18 (mc, 1 H, 3-H), 7.27 (br. s, 1
H, 3-H) ppm. 13C NMR (50.3 MHz, CDCl3): δ ϭ 26.5, 27.3, 28.4,
32.4, 32.8, 41.8 (6 t, 6 CH2), 51.75 (q, OMe), 124.8, 125.5, 129.0,
141.0 (s, t, d, s, C-2Ј, C-lЈ, C-3, C-2), 167.9 (s, C-1) ppm. IR (gas
phase): ν˜ ϭ 3055 cmϪ1 (ϭCϪH), 2930 (CϪH), 2855 (CH2), 1630
1H NMR (200 MHz, CDCl3):
δ ϭ 1.47Ϫ1.58, 1.73Ϫ1.85,
2.25Ϫ2.36 (3 m, 4 H, 2 H, 4 H, 5 CH2), 3.74 (s, 1 H, CO2Me), 5.80
(d, J ϭ 16.0 Hz, 1 H, 2-H), 6.31 (t, J ϭ 7.0 Hz, 1 H, 2Ј-H), 7.28
(d, J ϭ 16.0 Hz, 1 H, 3-H) ppm. 13C NMR (50.3 MHz, CDCl3):
δ ϭ 25.8, 26.1, 27.1, 29.0, 31.8 (5 t, CH2), 51.3 (q, CO2Me), 114.1,
141.9, 143.8, 149.2 (d, s, 2 d, C-2Ј, C-1Ј, C-3, C-2), 168.1 (s, C-1)
ppm. IR (film): ν˜ ϭ 3010 cmϪ1 (ϭCϪH), 2930, 2855, 1435 (CϪH),
1730 (CϭO), 1620 (CϭC), 1170 (CϪOϪC). C11H16O2 (180.25):
calcd. C 73.30, H 8.95; found C 72.79, H 8.98.
(E)-2-(Cyclohept-1-enyl)styrene (24): Nonaflation of 1h (0.920 g,
5.00 mmol) with NfF (3.02 g, 10.0 mmol) was performed with
nBu4NF (0.90 mmol) in THF (0.9 mL) according to GP2. After
addition of KOAc (0.343 g, 3.50 mmol), K2CO3 (0.602 g,
4.36 mmol), Pd(OAc)2 (0.039 g, 0.17 mmol), styrene (0.546 g,
5.25 mmol) and DMF (6 mL), the mixture was stirred at 80 °C for
6 h, followed by the usual workup and CC (hexane/EtOAc, 10:1),
to afford 24[34] (0.630 g, 64% yield) as a yellow oil. 1H NMR
(200 MHz, CDCl3): δ ϭ 1.35Ϫ1.85, 2.30Ϫ2.50 (2 m, 6 H, 4 H,
CH2), 6.04 (t, J ϭ 7.0 Hz, 1 H, 2Ј-H), 6.46, 6.76 (2 d, J ϭ 16.0 Hz,
1 H each, 1-H, 2-H), 7.10Ϫ7.45 (m, 5 H, Ph) ppm. 13C NMR
(50.3 MHz, CDCl3): δ ϭ 26.3, 26.8, 27.3, 28.8, 32.2 (5 t, CH2),
124.7, 135.5, 136.9 (3 d, C-2Ј, C-2, C-1), 126.2 126.8, 128.5, 138.1
(3 d, s, Ph), 143.1 (s, C-1Ј) ppm.
(CϭC), 1740 (CϭO), 1140 (CϪOϪC). GC/MS data: 27, tr
ϭ
9.0 min, (E)-26, ϭ 10.3 min, (Z)-26, ϭ 10.9 min. 27: MS (EI,
70 eV): m/z (%) ϭ 194 (41) [Mϩ], 180 (9), 162 (13), 152 (11), 133
(25), 119 (18), 105 (25), 95 (100), 79 (53), 67 (57), 55 (30), 41 (54),
32 (6). (E)-26: MS (EI, 70 eV): m/z (%) ϭ 194 (100) [Mϩ], 179 (12),
163 (38), 151 (61), 135 (47), 125 (39), 107 (25), 91 (60), 79 (47), 67
(21), 55 (18), 41 (35), 32 (15). (Z)-26: MS (EI, 70 eV): m/z (%) ϭ
194 (Ͻ1) [Mϩ], 179 (7), 165 (20), 149 (15), 133 (17), 125 (100), 111
(19), 95 (16), 79 (20), 67 (20), 55 (20), 41 (33), 32 (11).
Methyl (E)-4-Methylpenta-2,4-dienoate (28): Nonaflation of silyl
enol ether 1i (0.261 g, 2.00 mmol) with NfF (0.785 g, 2.60 mmol)
was performed in THF (1 mL) with KF (0.120 g, 2.07 mmol) and
dibenzo-18-crown-6 (0.144 g, 0.40 mmol) at 25 °C for 120 h accord-
ing to GP2. After addition of LiCl (0.127 g, 3.00 mmol), Et3N
(0.405 g, 4.00 mmol), Pd(OAc)2 (0.022 g, 0.10 mmol), methyl acryl-
ate (0.224 g, 2.60 mmol) and DMF (1 mL), the mixture was stirred
at 25 °C for 17 h, followed by the usual workup (n-pentane) and
CC (n-pentane/Et2O, 25:1), to provide 28[37] (0.080 g, 30% yield) as
a slightly yellowish oil. 1H NMR (270 MHz, CDCl3): δ ϭ 1.89 (dd,
J ϭ 1.3, 1.0 Hz, 3 H, Me), 3.76 (s, 3 H, CO2Me), 5.34Ϫ5.37 (m, 2
H, 5-H), 5.88 (d, J ϭ 15.8 Hz, 1 H, 2-H), 7.37 (dd, J ϭ 15.8, 0.5 Hz,
1 H, 3-H) ppm. 13C NMR (67.9 MHz, CDCl3): δ ϭ 17.9 (q, Me),
51.5 (q, CO2Me), 118.2 (t, C-5), 124.3 (d, C-2), 140.4 (s, C-4), 147.1
(d, C-3), 167.5 (s, C-1) ppm.
Methyl (E)-3-(Cyclohept-1-enyl)but-2-enoate (25): Nonaflation of
1h (0.920 g, 5.00 mmol) with NfF (3.02 g, 10.0 mmol) was per-
formed with nBu4NF (0.90 mmol) in THF (0.9 mL) according to
GP2. After addition of KOAc (0.343 g, 3.50 mmol), K2CO3
(0.602 g, 4.36 mmol), Pd(OAc)2 (0.039 g, 0.17 mmol), methyl cro-
tonate (0.525 g, 5.25 mmol) and DMF (6 mL), the mixture was
stirred at 80 °C for 4.5 h, followed by the usual workup and CC
(hexane/EtOAc, 10:1), to furnish 25 (0.389 g, 40% yield) as a yel-
1
lowish oil. H NMR (300 MHz, CDCl3): δ ϭ 2.27 (d, J ϭ 1.0 Hz,
3 H, Me), 1.46Ϫ2.36 (m, 10 H, 5 CH2), 3.70 (s, 1 H, CO2Me), 5.80
(q, J ϭ 1.0 Hz, 1 H, 2-H), 6.20 (t, J ϭ 7.0 Hz, 1 H, 2Ј-H) ppm.
13C NMR (75.5 MHz, CDCl3): δ ϭ 16.4 (q, Me), 26.3, 26.4, 28.6,
29.9, 32.3 (5 t, CH2), 50.8 (q, CO2Me), 113.2 (d, C-2Ј), 133.1 (d,
Methyl (E)-4-(tert-Butyl)penta-2,4-dienoate (9): Nonaflation of silyl
C-2), 146.9 (s, C-1Ј), 158.3 (s, C-3), 167.9 (s, C-1) ppm. IR (film): enol ether 1c (0.345 g, 2.00 mmol) with NfF (0.785 g, 2.60 mmol)
ν˜ ϭ 3010 cmϪ1 (ϭCϪH), 2925, 2850, 1435 (CH2), 1720 (CϭO),
was performed in a THF/DMF (2 mL, 1:1 v/v) mixture with KF
1690 (CϭC), 1165 (CϪOϪC). C12H18O2 (194.28): calcd. C 74.19, (0.120 g, 2.07 mmol) and dibenzo-18-crown-6 (0.144 g, 0.40 mmol)
H 9.34; found C 72.99, H 9.56; no correct elemental analysis could
be obtained for this compound.
at 25 °C for 40 h according to GP2. After addition of LiCl (0.127 g,
3.00 mmol), Et3N (0.405 g, 4.00 mmol), methyl acrylate (0.224 g,
Eur. J. Org. Chem. 2002, 3646Ϫ3658
3655

I. M. Lyapkalo, M. Webel, H.-U. Reißig
FULL PAPER
2.60 mmol) and Pd(OAc)2 (0.022 g, 0.10 mmol), the mixture was
0.175 mmol) and styrene (0.545 g, 5.25 mmol) were added to the
stirred at 25 °C for 64 h, followed by the usual workup (n-pentane) resulting solution. The resulting suspension was stirred at 75 °C for
and CC (gradient elution: n-pentane to n-pentane/Et2O, 50:1), to
provide 9 (0.146 g, 46% yield) as a slightly yellowish oil. According
to H NMR, the product contained 10Ϫ15% admixtures insepar-
6 h, followed by the usual workup and CC (hexane/EtOAc, 10:1),
to afford 19[34] (0.465 g, 51% yield) as a yellowish solid (m.p. ca.
25 °C).
1
able by CC. 1H NMR (270 MHz, CDCl3): δ ϭ 1.12 (s, 9 H, CMe3),
3.76 (s, 3 H, OMe), 5.05 (t, J ϭ 0.8 Hz, 1 H, 5-H), 5.28 (t, J ϭ
1.0 Hz, 1 H, 5-H), 6.13 (d, J ϭ 15.6 Hz, 1 H, 2-H), 7.46 (dt, J ϭ
15.6, 0.8 Hz, 1 H, 3-H) ppm. 13C NMR (67.9 MHz, CDCl3): δ ϭ
29.1 (q, CMe3), 35.1 (s, CMe3), 51.5 (q, OMe), 112.0 (t, C-5), 119.5
(d, C-2), 145.4 (d, C-3), 153.9 (s, C-4), 167.3 (s, C-1) ppm.
Dimethyl
4-[(E)-2-tert-Butoxycarbonylethen-1-yl]cyclohex-4-ene-
trans-1,2-dicarboxylate (30): Dimethyl 4-trimethylsiloxy-4-cyclo-
hexene-trans-1,2-dicarboxylate (1j) was generated from dimethyl fu-
marate (0.144 g, 1.00 mmol) and 2-(trimethylsiloxy)buta-1,3-diene
(0.171 g, 1.20 mmol) in toluene (1 mL) as described in the literat-
ure.[22] After the volatiles had been removed under vacuum, di-
benzo-18-crown-6 (0.054 g, 0.15 mmol), DMSO (0.8 mL), DMF
(0.2 mL), KF (0.060 g, 1.03 mmol) and NfF (0.453 g, 1.50 mmol)
were added consecutively to the crude 1j, and the resulting mixture
was stirred at room temperature for 60 h.* LiCl (0.021 g,
0.50 mmol), Et3N (0.132 g, 1.30 mmol), tert-butyl acrylate (0.170 g,
1.32 mmol) and Pd(OAc)2 (0.011 g, 0.05 mmol) were then added,
and the mixture was stirred at 75 °C for 5 h*, followed by the usual
workup (hexane/Et2O, 1:1) and CC (gradient elution: hexane/Et2O,
5:1 to 3:1), to provide 30 (0.191 g, 59% overall yield) as colourless
crystals (m.p. 66Ϫ68 °C); *complete conversion of the starting mat-
Methyl (E,E)-Dodeca-2,4-dienoate (14): Nonaflation of silyl enol
ether 1d (0.270 g, 1.26 mmol, E:Z ϭ 93:7) with NfF (0.507 g,
1.68 mmol) was performed with nBu4NF (0.25 mmol) in THF
(0.25 mL) according to GP2. After addition of nBu4NCl (0.330 g,
1.19 mmol), K2CO3 (0.337 g, 2.44 mmol), Pd(OAc)2 (0.011 g,
0.05 mmol), methyl acrylate (0.139 g, 1.61 mmol) and DMF
(6 mL), the mixture was stirred at 25 °C for 6 h, followed by the
usual workup and CC (hexane/EtOAc, 10:1), to give 14[32] (0.218 g,
82% yield, E,E/E,Z ϭ 95:5) as a yellow oil.
1-Phenylundeca-1,3-diene (29): Nonaflation of 1d (0.300 g,
1.40 mmol) with NfF (0.507 g, 1.68 mmol) was performed with
nBu4NF (0.25 mmol) in THF (0.25 mL) according to GP2. After
addition of KOAc (0.096 g, 0.98 mmol), K2CO3 (0.168 g,
1.21 mmol), Pd(OAc)2 (0.011 g, 0.05 mmol), styrene (0.145 g,
1.40 mmol) and DMF (3 mL), the mixture was stirred at 75 °C for
6 h, followed by the usual workup and CC (hexane/EtOAc, 10:1),
to furnish 29[38] (0.256 g, 80% yield, E,E/E,Z ϭ 95:5) as a slightly
yellowish oil. Compound (E,E)-29: 1H NMR (500 MHz, CDCl3):
δ ϭ 0.88 (t, J ϭ 5.0 Hz, 3 H, Me), 1.23Ϫ1.30, 1.41 (m, 8 H, quint.,
J ϭ 6.9 Hz, 2 H, 6-H to 10-H), 2.14 (q, J ϭ 6.9 Hz, 2 H, 5-H), 5.82
(dt, J ϭ 14.9, 6.9 Hz, 1 H, 4-H), 6.20 (dd, J ϭ 14.9, 10.4 Hz, 1 H,
3-H), 6.43 (d, J ϭ 15.6 Hz, 1 H, 1-H), 6.75 (dd, J ϭ 15.6, 10.4 Hz,
1 H, 2-H), 7.15Ϫ7.42 (m, 5 H, Ph) ppm. 13C NMR (125.8 MHz,
CDCl3): δ ϭ 14.1 (q, Me), 22.7, 22.7, 29.2*, 29.3 (4 t, CH2), 31.8
(t, C-9), 32.9 (t, C-5), 126.2, 127.0, 128.5 (3 d, Ph), 129.5 (d, C-2),
129.9 (d, C-1), 130.4 (d, C-3), 136.1 (s, C-4), 137.7 (s, Ph) ppm;
*double intensity. The following signals can be assigned to the com-
pound (E,Z)-29: 1H NMR (500 MHz, CDCl3): δ ϭ 1.54Ϫ1.58,
1.60Ϫ1.65 (2 m, 8 H, 2 H, 6-H to 10-H), 2.22Ϫ2.36 (m, 2 H, 5-H),
5.51Ϫ5.58 (m, 1 H, 4-H), 6.12Ϫ6.20 (m, 1 H, 3-H), 6.51 (d, J ϭ
15.5 Hz, 1 H, 1-H), 7.05Ϫ7.12 (m, 1 H, 2-H) ppm.
1
1
erial was detected by H NMR of the reaction mixture. H NMR
(270 MHz, CDCl3): 1.49 (s, H, CMe3), 2.20Ϫ2.49,
δ
ϭ
9
2.56Ϫ2.70, 2.84Ϫ3.00 (3 m, 2 H each, 6Ј-H, 1Ј-H to 3Ј-H), 3.71,
3.72 (2 s, 3 H, 3 H, 2 CO2Me), 5.74 (d, J ϭ 16.0 Hz, 1 H, 1-H),
6.09 (br. s, 1 H, 5Ј-H), 7.19 (d, J ϭ 16.0 Hz, 1 H, 2-H) ppm. 13C
NMR (67.9 MHz, CDCl3): δ ϭ 26.8, 28.6 (2 t, C-3Ј, C-6Ј), 28.1 (q,
CMe3), 40.8, 40.9 (2 d, C-1Ј, C-2Ј), 52.01, 52.03 (2 q, 2 CO2Me),
80.2 (s, CMe3), 118.3 (d, C-1), 133.8, 144.6 (2 d, C-2, C-5Ј), 132.9
(s, C-4Ј), 166.4 (s, CO2Bu-t), 174.58, 174.60 (2 s, 2 CO2Me) ppm.
MS (EI, 80 eV): m/z (%) ϭ 324 (4) [Mϩ], 293 (30) [Mϩ Ϫ MeO],
268 (43) [Mϩ Ϫ CH2ϭCMe2], 264 (15) [Mϩ Ϫ HCO2Me], 251 (18)
[Mϩ Ϫ tBuO], 250 (48) [Mϩ Ϫ tBuOH], 236 (13) [Mϩ Ϫ MeO Ϫ
tBu], 219 (23) [Mϩ Ϫ tBuOH ϪMeO], 218 (47) [Mϩ Ϫ tBuOH Ϫ
MeOH], 208 (66) [Mϩ Ϫ CO2Me Ϫ tBu], 191 (25) [Mϩ Ϫ
CO2Me Ϫ tBuOH], 190 (21) [Mϩ Ϫ HCO2Me Ϫ tBuOH], 176
(13) [Mϩ Ϫ CO2Me Ϫ tBuOH Ϫ Me], 158 (15) [Mϩ Ϫ HCO2Me Ϫ
tBuOH Ϫ MeOH], 149 (100) [Mϩ Ϫ 2 CO2Me Ϫ tBu], 131 (66)
[Mϩ Ϫ HCO2Me Ϫ CO2Me Ϫ tBuOH], 57 (74) [tBuϩ]. IR (film):
ν˜ ϭ 2975, 2955, 2925, 2850 cmϪ1 (ϭCϪH, CϪH), 1730, 1710 (Cϭ
O), 1640, 1620 (CϭC). C17H24O6 (324.4): calcd. C 62.95, H 7.46;
found C 62.90, H 7.31.
(R)-2-Methyl-5-[1-methyl-1-(trimethylsiloxy)ethyl]-3-(trimethyl-
siloxy)cyclohexa-1,3-diene (1k): (R)-Carvone (25.0 g, 166 mmol)
was treated with aqueous H2SO4 (50%, 169.5 g) as described in the
literature.[39] After the reaction mixture had been poured onto ice,
neutralised with 25% aqueous NH3 solution (pH ϭ 4Ϫ5) and ex-
tracted thoroughly with Et2O, the organic layer was washed suc-
cessively with water and brine and dried (MgSO4). After removal
of all volatile components under vacuum, the residue was carefully
dried overnight under high vacuum. The resulting mixture of (R)-
5-(1-hydroxy-1-methylethyl)-2-methylcyclohex-2-enone and 5-iso-
propyl-2-methylphenol (18.1 g, ratio ϭ 1:0.9) was dissolved in THF
Methyl (E)-5-Methylhexa-2,4-dienoate (15): Nonaflation of silyl
enol ether 1e (0.360 g, 2.50 mmol) with NfF (0.906 g, 3.00 mmol)
was performed with nBu4NF (0.45 mmol) in THF (0.45 mL) ac-
cording to GP2. After addition of nBu4NCl (0.695 g, 2.50 mmol),
K2CO3 (0.690 g, 5.00 mmol), Pd(OAc)2 (0.022 g, 0.10 mmol),
methyl acrylate (0.645 g, 7.50 mmol) and DMF (8 mL), the mixture
was stirred at 25 °C for 6 h. Isolation and purification as described
above provided 15[33] (0.245 g, 70% yield).
(E)-(2-Cyclohex-1-enyl)styrene (19) from Cyclohexanone by Depro-
tonation followed by Nonaflation and Heck Coupling: A solution of
n-butyllithium in hexane (2.2 , 2.32 mL, 5.10 mmol) was added at (20 mL) and added dropwise at Ϫ78 °C to a solution of iPr2NLi
Ϫ78 °C to a solution of iPr2NH (0.516 g, 5.10 mmol) in THF
(80 mL). After the mixture had been kept for 1 h at Ϫ78 °C, cyclo-
hexanone (0.490 g, 5.00 mmol) was added and the mixture was
stirred for 1 h at Ϫ78 °C. Neat NfF (3.02 g, 10.0 mmol) was added
dropwise, and the reaction mixture was allowed to warm up to
room temp. overnight. After all the volatile components had been
removed under vacuum, DMF (6 mL) was added. KOAc (0.343 g,
3.50 mmol), K2CO3 (0.601 g, 4.38 mmol), Pd(OAc)2 (0.039 g,
in THF (200 mL), generated from nBuLi (80.0 mL, 192 mmol, 2.4
molar in hexanes) and iPr2NH (24.5 g, 242 mmol) (Ϫ78 °C to 0
°C, then down to Ϫ78 °C again). After the mixture had been stirred
at Ϫ78 °C for 1 h, Me3SiCl (32.0 g, 295 mmol) was added dropwise,
and the reaction mixture was allowed to warm up to room temp.
overnight. Workup (aqueous NaHCO3/hexane), extraction (hex-
ane), drying (Na2SO4), vacuum evaporation and fractional distilla-
tion afforded pure product 1k (14.9 g, 29% overall yield) as a yel-
3656
Eur. J. Org. Chem. 2002, 3646Ϫ3658

One-Pot Transformation of Silyl Enol Ethers into 1,3-Dienes
FULL PAPER
lowish oil (b.p. 99Ϫ100 °C/0.4 mbar). 1H NMR (270 MHz,
CDCl3): δ ϭ 0.11 (s, 9 H, Me2COSiMe3), 0.21 (s, 9 H, SiMe3),
Leverkusen, for generous donations of nonafluorobutylsulfonyl
fluoride and Dr. R. Zimmer for help in the preparation of this
1.16, 1.18 (2 s, 3 H each, Me2C), 1.68 (dd, J ϭ 3.9, 1.7 Hz, 3 H, manuscript. General support by the Fonds der Chemischen Indus-
MeCϭ), 1.96Ϫ2.15 (m, 2 H, 6-H), 2.42 (ddd, J ϭ 13.8, 8.7, 3.4 Hz, trie and by the Schering AG is gratefully appreciated.
1 H, 5-H), 4.90 (d, J ϭ 3.4 Hz, 1 H, 4-H), 5.53 (mc, 1 H, 1-H)
ppm. 13C NMR (67.9 MHz, CDCl3): δ ϭ 0.2 (q, SiMe3), 2.6 (q,
Me2COSiMe3), 17.2 (q, MeCϭ), 24.9 (t, C-6), 27.1, 27.4 (2 q,
Me2C), 46.4 (d, C-5), 76.3 (s, Me2C), 104.5 (d, C-4), 123.4 (d, C-
1), 131.7 (s, C-2), 149.8 (s, C-3) ppm.
[1] [1a]
Organikum, 21. Ed.; Wiley-VCH: Weinheim 2001, pp.
[1b]
408Ϫ411.
H. Beyer, W. Walter; Lehrbuch der Organischen
Chemie; 23. Ed.; (Eds.: W. Walter, W. Franke); Hirzel:
Stuttgart, Leipzig 1998, pp. 408Ϫ409. [1c] A. Streitwieser, C. H.
Heathcock, E. M. Kosower; Organische Chemie; 2. Ed.; Wiley-
VCH: Weinheim 2001, p. 1028. [1d] F. A. Carey, R. J. Sundberg,
Organische Chemie; (Eds.: H.-J. Schäfer, D. Hoppe, G. Erker);
Wiley-VCH: Weinheim 1995, pp. 1161Ϫ1162.
(1R,2S,6R,7R,11R)-9-Methyl-11-[1-methyl-1-(trimethylsiloxy)-
ethyl]-3,5-dioxo-4-phenyl-4-azatricyclo[5.2.2.02,6]undec-8-en-8-yl
Nonaflate (2l): N-Phenylmaleimide (0.246 g, 2.00 mmol) was added
to a solution of the trimethylsilyl enol ether 1k (0.625 g, 2.00 mmol)
and diisopropyl ethylamine (1 drop) in toluene (1 mL), and the
reaction mixture was stirred for 72 h at room temperature,[23] fol-
lowed by removal of the volatiles under vacuum. The residue (single
stereoisomer of 1l, according to 1H NMR) was dissolved in a
DMF/THF mixture (3 mL, 1:1 v/v), and NfF (0.785 g, 2.60 mmol),
KF (0.120 g, 2.07 mmol) and dibenzo-18-crown-6 (0.108 g,
0.30 mmol) were added consecutively. The resulting mixture was
stirred for 67 h at room temperature. The generated nonaflate 2l
failed to react either under standard (methyl acrylate, Pd(OAc)2,
LiCl, Et3N, 50 °C, 20 h) or under drastic [styrene, Pd(OAc)2,
KOAc, K2CO3, 100 °C, 24 h] Heck coupling conditions and was
recovered as a single stereoisomer (0.973 g, 70% yield, colourless
glassy solid) from both experiments after the usual aqueous
workup (Et2O) and CC (gradient elution: hexane/Et2O, 5:1 to 4:1
to 5:2 to 1:1). Compound 2l: 1H NMR (270 MHz, CDCl3): δ ϭ
0.07 (s, 9 H, SiMe3), 1.14, 1.32 (2 s, 3 H, 3 H, Me2C), 1.50,
1.67Ϫ1.85 (ddd, J ϭ 11.8, 5.0, 3.0 Hz, m, 1 H, 2 H, 5-H, 6-H),
1.85 (s, 3 H, MeCϭ), 2.96Ϫ3.06, 3.26Ϫ3.30, 3.49Ϫ3.51 (3 m, 2 H,
1 H, 1 H, 3-H, 8-H, 4-H, 7-H), 7.26Ϫ7.31 7.32Ϫ7.47 (2 m, 2 H, 3
H, Ph) ppm. 13C NMR (125.8 MHz, CDCl3): δ ϭ 2.2 (q, SiMe3),
15.1 (q, MeCϭ), 27.0 (t, C-5), 28.2, 29.2 (2 q, Me2C), 37.4, 39.5,
43.7, 46.8, 51.3 (5 d, C-6, C-7, C-8, C-3, C-4), 74.4 (s, Me2C), 126.5,
128.9, 128.4 (3 d, Ph), 129.2, 131.7, 140.3 (3 s, CPhN, C-10, C-9),
175.2, 176.7 (2 s, C-1, C-2) ppm. 19F NMR (470 MHz, CDCl3):
δ ϭ Ϫ126.98 to Ϫ125.59, Ϫ121.34 to Ϫ121.17 (2 m, 2 F, 2 F, CF2-
2, CF2-3), Ϫ110.86 (d*, J ϭ 259.2 Hz, 1 F, CF2-1), Ϫ110.14 (d*,
J ϭ 259.2 Hz, 1 F, CF2-1), Ϫ81.07 (br. t, J ϭ 9.7 Hz, 3 F, CF3)
ppm; *further complex splitting by 19FϪ19F couplings. MS (EI,
80 eV): m/z (%) ϭ 696 (1) [Mϩ ϩ 1], 695 (3) [Mϩ], 681 (2)
[Mϩ ϩ 1 Ϫ Me], 680 (6) [Mϩ Ϫ Me], 638 (4) [Mϩ ϩ 1 Ϫ SiMe2] or
[Mϩ ϩ 1 Ϫ Me2CϭO], 637 (11) [Mϩ Ϫ SiMe2] or [Mϩ Ϫ
Me2CϭO], 412 (1) [Mϩ Ϫ CF3(CF2)3SO2], 397 (2) [Mϩ Ϫ
CF3(CF2)3SO2 Ϫ Me], 396 (1) [Mϩ Ϫ CF3(CF2)3SO2O], 340 (1)
[Mϩ Ϫ CF3(CF2)3SO2 Ϫ Me2SiϭCH2], 322 (1) [Mϩ Ϫ CF3-
(CF2)3SO2 Ϫ Me3SiOH], 306 (1) [Mϩ Ϫ CF3(CF2)3SO2O Ϫ
Me3SiOH], 247 (3) [C11H19O4Sϩ], 246 (9) [C11H18O4Sϩ], 181 (1)
[C4F7ϩ], 175 (1) [C10H9NO2ϩ], 174 (1) [C10H8NO2ϩ], 173 (1)
[C10H7NO2ϩ], 159 (2) [C10H9NOϩ], 147 (3) [PhN(CO)2ϩ], 131
[2]
[2a] R. F. Heck, Org. React. (N. Y.) 1982, 27, 345Ϫ390. [2b] R. F.
Heck, in Comprehensive Organic Synthesis (Eds.: B. M. Trost,
[2c]
I. Fleming); Pergamon Press: Oxford, 1991; Vol. 4.
L. E.
A. de
[2d]
Overman, Pure Appl. Chem. 1994, 66, 1423Ϫ1430.
Meijere, F. E. Meyer, Angew. Chem. 1994, 106, 2473Ϫ2506; An-
[2e]
gew. Chem. Int. Ed. Engl. 1994, 33, 2379Ϫ2411.
T. Jeffery,
In Advances in Metal-Organic Chemistry; L. S. Liebeskind, Ed.;
Jai Press Inc: Greenwich, CT, 1996, Vol. 5. [2f]J. T. Link, L. E.
[2g]
Overman, Chemtech 1998, 28, 19Ϫ26.
G. T. Crisp, Chem.
Soc. Rev. 1998, 27, 427Ϫ436. [2h] J. T. Link, L. E. Overman, in
Metal-Catalyzed Cross-Coupling Reactions (Eds.: F. Diederich,
[2i]
P. J. Stang), Wiley-VCH: New York, 1998.
I. P. Beletskaya,
A. V. Cheprakov, Chem. Rev. 2000, 100, 3009Ϫ3066 and refer-
ences cited therein.
[3] [3a]
W. J. Scott, J. E. McMurry, Acc. Chem. Res. 1988, 21,
[3b]
47Ϫ54.
K. Ritter, Synthesis 1993, 735Ϫ762.
[4] [4a]
S. Bräse, A. de Meijere, Angew. Chem. 1995, 107,
2741Ϫ2743; Angew. Chem. Int. Ed. Engl. 1995, 34, 2545Ϫ2547.
[4b]
K. Voigt, P. von Zezschwitz, K. Rosauer, A. Lansky, A.
Adams, O. Reiser, A. de Meijere, Eur. J. Org. Chem. 1998,
1521Ϫ1534.
Wada, Y. Ieki, M. Ito, Synlett 2002, 1061Ϫ1063. For the use
of aryl nonaflates, see
[4c]
[4d]
S. Bräse, Synlett 1999, 1654Ϫ1656.
A.
[4e]
M. Rottlaender, P. Knochel, J. Org.
Chem. 1998, 63, 203Ϫ208.
I. M. Lyapkalo, M. Webel, H.-U. Reißig, Eur. J. Org. Chem.
2002, 1015Ϫ1025.
M. Webel, H.-U. Reißig, Synlett 1997, 1141Ϫ1142.
M. Webel, Dissertation, Technische Universität Dresden, 2000.
I. M. Lyapkalo, M. Webel, H.-U. Reißig, Eur. J. Org. Chem.
2001, 4189Ϫ4194.
I. M. Lyapkalo, M. Webel, H.-U. Reissig, Synlett 2001,
1293Ϫ1295.
I. M. Lyapkalo, H.-U. Reißig, unpublished results.
A. Burini, S. Cacchi, P. Pace, B. R. Pietroni, Synlett 1995,
677Ϫ679.
The trans arrangement of the CO2Me groups in 10b was rigor-
ously established by the selective proton decoupling method.
Any possible epimerisations and/or cycloreversions of 10b
while boiling in PhCl were ruled out by a control experiment
conducted in the absence of DDQ under otherwise identical
conditions, thereafter indicating no changes of a sample of 10b.
For comparison, a [4 ϩ 2] cycloaddition between methyl acryl-
ate and (E)-penta-2,4-dienoic acid required heating at 110 °C
to proceed, giving all four possible isomers, see: L. E. Over-
man, G. F. Taylor, K. N. Houk, L. N. Domelsmith, J. Am.
Chem. Soc. 1978, 100, 3182Ϫ3189.
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
(100) [CF2ϭCFCF2 or Me3SiOϭCMe2ϩ], 119 (2) [PhNCOϩ], 77
ϩ
(2) [C6H5ϩ], 75 (6), 73 (25) [Me3Siϩ], 69 (2) [CF3ϩ], 43 (2)
[HNCOϩ]. IR (film): ν˜ ϭ 2980 cmϪ1 (br., ϭCϪH, CϪH), 1715
(CϭO), 1600 (CϭC), 1415, 1145 (SO2), 1240, 1200 (CϪF).
C27H30F9NO6SSi (695.7): calcd. C 46.62, H 4.35, N 2.01; found C
46.64, H 4.24, N 1.95.
[15]
[16]
[17]
We also observed this compound in the one-pot reaction, but
could not separate it from the main coupling product 9.
P. J. Stang, M. Hanack, L. R. Subramanian, Synthesis 1982,
85Ϫ126.
Alternatively, an E,Z isomerisation of the C,C double bond
favouring the thermodynamically more stable E isomer may be
operative under the reaction conditions, see: W. J. Scott, M. R.
Pen˜a, K. Swärd, S. J. Stoessel, J. K. Stille, J. Org. Chem. 1985,
Acknowledgments
Generous support by the Deutsche Forschungsgemeinschaft and
the Alexander von Humboldt foundation (research fellowship for
I. M. L.) is most gratefully acknowledged. We thank Bayer AG,
50, 2302Ϫ2308; cf. ref.[2a]
.
[18]
W. Yu, Z. Jin, Tetrahedron Lett. 2001, 42, 369Ϫ372.
Eur. J. Org. Chem. 2002, 3646Ϫ3658
3657

I. M. Lyapkalo, M. Webel, H.-U. Reißig
FULL PAPER
[19]
[30] [30a]
The detected NMR signals matched those described in the lit-
P. Seneci, M. Caspani, F. Monti, L. Carrano, S. Lociuro,
erature: M. Hesse, H. Meier, B. Zeeh; Spectroscopic Methods
in Organic Chemistry; Thieme, Stuttgart, 1997, p. 186.
The results after 100% conversion of 2c in the presence of
R. Ciabatti, Synth. Commun. 1997, 27, 795Ϫ810. [30b] 1H NMR
(270 MHz, CDCl3): δ ϭ 1.38 (s, 9 H, CMe3), 3.95 (s, 6 H, 2
CO2Me), 8.26 (d, J ϭ 1.6 Hz, 2 H, 4-H, 6-H), 8.50 (t, J ϭ
1.6 Hz, 1 H, 2-H) (cf. 1H NMR of the closely related diethyl
ester: J. Voss, W. Schmueser, K. Schlapkohl, J. Chem. Res. S
[20]
Pd(OAc)2 and methyl acrylate were as follows: neat DMF,
LiCl, Li2CO3 (a base weaker than Et3N), room temp., 20 h
resulted exclusively in elimination; neat DMF, Et4NCl·H2O,
iPr2NEt gave a 5:1 ratio of 3,3-dimethylbutyne 11 to 9 after
16 h at room temp.; similar results were obtained in DMSO as
a solvent, but 2c remained fully intact after exposure to stoichi-
ometric iPr2NEt in hexane at room temp. for 26 h.
(Synopses) 1977, 6, 144Ϫ145; see also ref.[13]
.
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