(Trimethylstannyl)vinyl cuprates: Generation and conjugate addition reactions

Article abstract of DOI:10.1021/jo960245n

A new convenient route to the bis[(trimethylstannyl)vinyl] cuprate reagent 9 is described. Its addition to α,β-unsaturated ketones has been studied. Bis(trimethylsilyl)acetamide (BSA) was found to activate 1,4-conjugate addition of 9 to α,β-unsaturated ketone esters without concomitant reduction of the double bond.

Full text of DOI:10.1021/jo960245n

5406
J . Org. Chem. 1996, 61, 5406-5413
(Tr im eth ylsta n n yl)vin yl Cu p r a tes: Gen er a tion a n d Con ju ga te
Ad d ition Rea ction s
Oswy Z. Pereira and Tak-Hang Chan*
Department of Chemistry, McGill University, Montreal, Quebec H3A 2K6, Canada
Received February 6, 1996X
A new convenient route to the bis[(trimethylstannyl)vinyl] cuprate reagent 9 is described. Its
addition to R,â-unsaturated ketones has been studied. Bis(trimethylsilyl)acetamide (BSA) was found
to activate 1,4-conjugate addition of 9 to R,â-unsaturated ketone esters without concomitant
reduction of the double bond.
Sch em e 1
In tr od u ction
Organostannanes have enjoyed considerable use in
organic synthesis recently, especially as new, mild, and
efficient methods for their preparation have been de-
veloped.1a In particular, the deployment of vinylstan-
nanes2,3 as geometrically defined, latent vinyl anions has
been reported in several recent accounts of natural
product synthesis including rapamaycin,4 taxol,5 and
avermectins.6
A useful method of preparing vinylstannanes is to use
vinylstannyl cuprates 1 as the precursors. Reactions of
1 with diverse electrophiles give readily vinylstannanes.
Of particular interest is the reaction of 1 with R,â-
unsaturated ketones to give regioselectively the 1,4-
conjugate adducts (eq 1).7 Recently, Marino8 and Pulido/
and a study of the conjugate addition of these reagents
with R,â-unsaturated ketones and keto esters.
Resu lts a n d Discu ssion
(1) Gen er a tion of Mixed (Tr im eth ylsta n n yl)vin yl
Cu p r a tes. The conventional methods11 of generating
mixed stannyl cuprate via trimethylstannyl lithio species,
when applied to the addition to acetylene in order to
obtain the vinylstannyl reagents (Scheme 1), gave low
yields (ca. < 10%). We thus adopted the Lipshutz
protocol12 by starting from different organolithium re-
agents according to Scheme 2. Addition of 2 equiv of
trimethyltin hydride to the cuprate reagents 2 gave the
mixed trimethylstannyl cuprates 3 in good yields. Acety-
lene was then passed slowly into the mixture at -78 °C
to give mixed (trimethylstannyl)vinyl cuprates 4. The
mixed cuprates 4 were then reacted with cyclohex-2-
enone in the presence of Et3SiCl, and the products were
analyzed. It is clear from results summarized in Table
1 that in the case of 4a (entry 1), 4b (entry 2), and 4c
(entry 3), incomplete addition to acetylene occurred,
leading to addition products 5 (derived from 3, R ) Me,
or Ph or tBu) and 6 (derived from 4a , 4b, or 4c). In the
case of 4d (R ) nBu), little addition product 5 was
obtained, indicating that the addition of 4d to acetylene
was complete. Ratios of the trimethylstannyl versus
(trimethylstannnyl)vinyl versus alkyl adducts 5, 6, and
7, respectively, were readily determined from the integral
values of the respective enolic protons that characteristi-
cally occurred at 4.5-6.0 ppm. However, for most of the
enones examined, transfer of the n-butyl group competed
Fleming9 have independently described the addition of
tri-n-tributylstannyl cuprates to acetylene as a way to
afford the cis-tri-n-butylstannyl)vinyl cuprate reagents.
We became interested in the use of various cis-
(trimethylstannyl)vinyl cuprate reagents because of the
greater ease of manipulation and spectral simplicity of
the trimethyltin moiety relative to the tri-n-butyltin
reagents. We have recently reported10 in preliminary
form a novel preparation of various (trimethylstannyl)-
vinyl cuprates. We report here full experimental details
X Abstract published in Advance ACS Abstracts, J uly 15, 1996.
(1) (a) Pereyre, M.; Quintard, J -P.; Rahm, A. Tin in Organic
Synthesis; Butterworths: London, 1987. (b) Smith, P. J . Toxicological
Data on Organotin Compounds: International Tin Research Inst.:
London, 1978.
(2) Corey, E. J .; Wollenberg, R. H. J . Am Chem. Soc. 1974, 96, 5581.
(3) Lipshutz, B. H.; Lee, J . I. Tetrahedron Lett. 1991, 7211-7214.
(4) Nicolaou, K. C.; Chakraborty, A. D.; Piscopio, A. D.; Minowa,
N.; Bertinato, P. J . Am. Chem. Soc.1993, 115, 4419-4420.
(5) Queneau, Y.; Krol, W. J .; Bornmann, W. G.; Danishefsky, S. J .
J . Org. Chem. 1992, 57, 4043-4047.
(6) Milburn-Booker, K. I.; Haffernan, G. D.; Parsons, P. J . J . Chem.
Soc., Chem. Commun. 1992, 350-351.
(7) Kozlowski, J . A.; Comprehensive Organic Synthesis; Trost, B. M.,
Fleming, I., Eds.; Pergammon Press: New York, 1991; Vol. 1, p 169.
(8) Marino, J . P.; Emonds, V. M.; Stengel, P. J .; Oliveira, A. R. M.;
Simonelli, F.; Ferreira, J . T. B. Tetrahedron Lett. 1992, 33, 49-52.
(9) Barbero, A.; Cuadrado, P.; Fleming, I.; Gonzalez, A. M.; Pulido,
F. J . J . Chem. Soc., Chem. Commun. 1992, 351.
(11) Sato, T. Synthesis 1990, 259-270 and references cited therein.
(12) Lipshutz, B. H.; Ellworth, E. L.; Dimock, S. H.; Reuter, D. C.
Tetrahedron Lett. 1989, 30, 2065-2068.
(10) Pereira, O. Z.; Chan, T. H. Tetrahedron Lett. 1995, 36, 8749-
8752.
S0022-3263(96)00245-9 CCC: $12.00 © 1996 American Chemical Society

(Trimethylstannyl)vinyl Cuprates
J . Org. Chem., Vol. 61, No. 16, 1996 5407
Sch em e 2
Ta ble 1. Ad d ition of Cu p r a tes 4 a n d 9 to r,â-Un sa tu r a ted En on es
a
See ref 13a.
with the transfer of the (trimethylstannyl)vinyl moiety
to the enone. With cyclohexenone, under careful control
of reaction conditions (-100 °C, Table 1, entry 4), adduct
6 was obtained in 79% yield versus the butyl transfer
adduct 7 (R ) nBu) obtained in 9% yield. Changing Et3-
SiCl to BF3OEt2 as the promoting reagent served only to
promote transfer of the butyl group (Table 1, entry 5).
Similar transfer of the butyl group from 4d was observed

5408 J . Org. Chem., Vol. 61, No. 16, 1996
Pereira and Chan
Sch em e 3
through silica-catalyzed Hoffmann elimination of the
initially formed amide adduct 15, although direct γ-depro-
tonation by cuprate 10 cannot be excluded. This result
has also led us to prepare the mixed (trimethylstannyl)-
vinylamide cuprate 16 via the mixed reagent 17 formed
by the addition of only 1 equiv of trimethyltin hydride to
10. Indeed, the mixed cuprate 16 reacted at -35 °C with
cyclohexenone with complete selective transfer of the
(trimethylstannyl)vinyl residue (63%) but, as expected,
with somewhat poorer reactivity (over 2 h) than the homo
reagent 9.
(3) Con ju ga te Ad d ition Rea ction s to r,â-Un sa tu r -
a ted Keto Ester s. In contrast to enones, cuprate
addition to R,â-unsaturated ketoesters has received little
attention despite the increasing use of these Michael
acceptors as useful building blocks in synthesis.15 Specif-
ically, conjugate cuprate addition of vinylstannanes to
these substrates has not been studied. As part of our
program on the synthesis of highly functionalized decalin
systems,16 we examined the conjugate addition of (tri-
methylstannyl)vinyl cuprate 9 to R,â-unsaturated keto
esters.
We first examined the reaction of ketoester 18 toward
the mixed stannyl cuprate 4d . Not unexpectedly, expo-
sure of keto ester 18 to 4d in the presence of Et3SiCl at
-78 °C afforded products of both butyl and vinylstannyl
transfer. Unlike the case of cyclohex-2-enone though,
preferential transfer of the butyl group occurred, afford-
ing the butyl adduct 19 in 42% yield versus 31% of the
vinylstannyl adduct 20 (Table 2, entry 1). The use of the
mixed thienyl cuprate 4e afforded a marginally better
yield (46%, Table 2, entry 2) of the desired product 20.
To our surprise, in both cases, there was present in the
products a small amount of 1,4-reduction product 21. Of
greater concern was the fact that when the reaction was
carried out on a longer running, larger scale (700 mg)
run with 4e, the yield of the reduction product 21 was
increased substantially to 35% (Table 2, entry 3).
for other R,â-unsaturated ketones such as 4-methylpent-
3-en-2-one (Table 1, entry 6) and 4,4-dimethylcyclohex-
2-enone (Table 1, entry 7).
Since the thienyl group was reported13b to not compete
with the tributylstannyl group, we prepared the mixed
thienyl (trimethylstannyl)vinyl cuprate reagent 4e ac-
cording to Scheme 3. When 4e was reacted with cyclo-
hex-2-enone under similar conditions, 6 (Table 1, entry
8) was obtained as the only product in 82% yield.
(2) Gen er a t ion of Bis[(t r im et h ylst a n n yl)vin yl]
Cu p r a te 9. In his work on hindered enones, Marino8
reported best results with homo bis[(tri-n-butylstannyl)-
vinyl] cuprate 8 and attributed this outcome to its
superior reactivity. Given the results from the mixed
(trimethylstannyl)vinyl cuprates 4, we decided to explore
the reactivity of the trimethylstannyl analog 9. After
considerable experimentation, we found the protocol
delineated in Scheme 4 to give synthetically useful yields
of the reagent 9. LDA was added to CuCN and LiCl in
THF at -78 °C to generate a deep royal blue solution of
10. Trimethyltin hydride was then added to give an
intense yellow solution of 11. The formation of 11 was
confirmed by its reaction with an activated alkyne,
methyl 2-butynoate (12), at -78 °C to give the addition
product 13 in 94% yield. Addition of 11 to acetylene did
not occur at -78 °C but at -50 °C, when formation of
the reagent 9 as a bright yellow solution took place.
Addition of 9 to cyclohex-2-enone, 4,4-dimethylcyclohex-
2-enone, and 4,4-bis(ethoxycarbonyl)cyclohex-2-enone
(Table 1, entries 9-11) gave transfer of the (trimethyl-
stannyl)vinyl moiety in good yields.
The mechanism by which this reduction occurs remains
unclear at present. However, it is perhaps noteworthy
that treatment of keto ester 18 with the bisbutyl cuprate
22a under similar conditions yielded the expected butyl
adduct 19 in 93% yield. No reduction product was
observed. This tends to preclude reduction of the R,â-
unsaturated unit via a mechanism involving â-elimina-
tion of the butyl ligand, followed by reductive elimination
with concomitant hydride transfer.
More significantly, the bis[(trimethylstannyl)vinyl] cu-
prate reagent 9 showed an even greater propensity to
effect 1,4-reduction. In the reaction of 9 with 18 under
the same reaction conditions, an almost 1:1 ratio of the
stannylvinyl adduct 20 to the reduced product 21 (Table
2, entry 5) was obtained. The presence of the reduction
product appeared to be quite sensitive to the nature of
the substituents at the 4-position. With the unsubsti-
tuted keto ester 22, the stannylvinyl adduct 23 was
obtained exclusively, albeit in lower yield (52%, Table 2,
entry 6). On the other hand, with the sterically more
demanding keto ester 24, only the reduction product 25
Formation of the amidocuprate 10 has not previously
been reported in the literature. Its existence in the
present case is strongly implicated by the observation
that when cyclohex-2-enone and Et3SiCl were added to
the deep royal blue solution of 10, the 1,3-diene 14 could
be obtained in 60% unoptimized yield. J ung14 has
demonstrated that 1,3-dienes of type 14 are not available
through simple base-mediated deprotonation at the
γ-position of cyclohex-2-enones under either kinetic or
thermodynamic conditions. In all probability, 14 arose
(15) (a)Liu, H.-J .; Ngooi, T. K. Can. J . Chem. 1984, 62, 2676. (b)
Deslongchamps, P.; Lavallee, J . F. Tetrahedron Lett. 1988, 29, 5117.
(c) Lejeune, J .; Lallemand, J . Y. Tetrahedron Lett. 1991, 32, 2621-
2624.
(16) (a) Pereira, O. Z.; Chan, T. H. J . Org. Chem. 1994, 59, 6710-
6716. (b) Chan T. H.; Prasad, C. V. C. J . Org Chem. 1987, 52, 110-
119; 1987, 52, 120; 1989, 54, 3242. (c) Chan, T. H.; Schwerdtfeger, A.
E. J . Org.Chem. 1991, 56, 3294-3298.
(13) (a) Wang, Y.; Gladysz, J . A. J . Org. Chem. 1995, 60, 903-909.
(b) Lipshutz, B. H. Synlett 1989, 119-128 and references cited therein.
(c) Lipshutz, B. H.; Reuter, D. C. Tetrahedron Lett. 1989, 30, 4617.
(14) J ung, M. E.; McCombs, C. A. Tetrahedron Lett. 1976, 2935-
2938.

(Trimethylstannyl)vinyl Cuprates
J . Org. Chem., Vol. 61, No. 16, 1996 5409
Sch em e 4
was obtained (65%, entry 7), after 24 h at -50 °C, with
no detectable amount of the stannylvinyl adduct.
In all probability, the low reduction potential of the
R,â-unsaturated keto ester favors single electron transfer
(SET) over ligand transfer from the presumed intermedi-
ate Cu(III) complex,17 especially in the more sterically
encumbered substrate such as 24. The absence of
reduction product in the case of the keto ester 22 for
which the reaction was complete in 15-20 min tends to
suggest that a combination of both steric and electronic
factors is involved in promoting reduction.
effect of this reagent on the conjugate addition of
stannnyl cuprate 9 to keto esters is quite dramatic.
Thus, with the keto ester 18, a near-quantitative yield
(92%, Table 2, entry 9) of the stannylvinyl adduct 28 was
obtained with no trace of the reduction product 21. Even
with the hindered ketoester 24,19 a complete reversal of
product selectivity was observed, affording the adduct 29
exclusively in 79% yield (Table 2, entry 10). It is
interesting to observe that BSA activation toward enones
is less pronounced. It is comparable to Et3SiCl (Table 2,
entries 11 and 12) and is otherwise not remarkable.
(4) Bis(tr im eth ylsilyl)a ceta m id e (BSA) a s a Novel
Activa tin g Agen t. In order to circumvent the reduction
reaction, activation of either the cuprate reagent or the
enone-ester greater than that provided by Et3SiCl is
required. Lipshutz,18 among others, has published ex-
tensively on the nature of such activation and has
invoked σ-donation to explain the accelerated rate effect,
observed in cuprate-mediated Michael addition. Fur-
thermore, he found trimethylsilyl cyanide (TMSCN) to
be superior in this respect and implicated π-donation to
explain the enhanced yields. In our hands, TMSCN,
regardless of the order of addition, reacted instead, in a
1,4-fashion, with ester 18 to give the cyanoester 26 in
65% yield (Table 2, entry 8). It should be noted that,
under analogous conditions, the use of TMSCN in lieu
of Et3SiCl in the reaction of 9 with cyclohexenone did not
lead to similar cyano adduct 27 (Scheme 3).
Con clu sion
In conclusion, we have demonstrated a convenient
route to the bis [(trimethylstannyl)vinyl] cuprate 9
through the intermediacy of the novel amido cuprate 10.
Additionally, cuprate 9 was found to be an effective
reagent for the introduction, via conjugate addition, of
the cis-(trimethylstannyl)vinyl unit to substituted cyclo-
hex-2-enones. Finally we have illustrated BSA to be far
superior to existing activating agents in the 1,4-addition
of cuprate 9 to sterically encumbered keto esters, provid-
ing (trimethylstannyl)vinyl adducts in high yields.
Exp er im en ta l Section
Distillation temperatures refer to short-path distillations.
Melting points are uncorrected. THF was distilled from
sodium/benzophenone ketyl. All other solvents when used dry
were distilled under argon from calcium hydride. Prior to use,
acetylene was passed through two -78 °C cooling towers (to
remove acetone) separated by a NaOH/CaCl2 drying tube and
then allowed to pass over a column of Drierite before collection
in an inverted burette over paraffin oil. BSA was used
acetamide free. Copper cyanide and lithium chloride were
dried at 120 °C in a vacuum oven(<1 mm) for 16 h prior to
use. Chromatography was performed on Merck Kieselgel 60
(mesh 70-230) using distilled solvents. Unless otherwise
indicated, 1H NMR was recorded in CDCl3 on 200, 270, or 500
MHz spectrometers. 13C NMR spectra were recorded at 50,
Trimethyl phosphite has been used extensively in
cuprate chemistry. We found, however, that under the
present reaction conditions P(OMe)3 did not have any
observable effect on the reaction outcome.
Bis(trimethylsilyl)acetamide (BSA) is well recognized
as a powerful silylating agent. As an amido enol ether,
BSA has good potential as a π-donor. We found that the
(19) Keto ester 24 was prepared in a manner akin to that described
for 18 by: Schanchez, I. H; Ortega, A.; Garcia, G.; Larraza, N. I.; Flores,
H. J . Synth. Commun. 1985, 15, 141-149 (see Experimental Section).
(17) Perlmutter, P. Conjugate Addition Reactions in Organic Syn-
thesis; Pergammon Press: New York, 1992; pp 5-27.
(18) (a) Lipshutz, B. H.; Dimock, S. H.; J ames, B. J . Am. Chem. Soc.
1993, 115, 9283-9284. (b) Lipshutz, B. H.; Sengupta, S. In Organic
Reactions; Paquette, L. A., Ed.; J ohn Wiley & Sons: New York, 1992;
Vol. 41, Chapter 2, pp 135-631.

5410 J . Org. Chem., Vol. 61, No. 16, 1996
Ta ble 2. Ad d ition of Cu p r a tes to r,â-Un sa tu r a ted En on es a n d Keto Ester s
Pereira and Chan
a
b
PMB ) p-methoxybenzyl. See ref 19. Large scale 700 mg run.
68, and 125 MHz in CDCl3. Chemical shifts (δ values) are
9.36 mmol) in dry THF (20 mL). The initial colorless solution
immediately turned mauve and then royal blue. After 40 min
the reaction was treated slowly, over 35 min, with Me3SnH
(1.51 g, 9.36 mmol). The color rapidly changed to black and
then to black/green and thence to an intense yellow. The
solution was kept at this temperature for 1 h and then treated
at -78 °C, in a closed system, with gaseous acetylene (via
inverted burette, acetone free) (262 mL, 12.0 mmol, 2.5 equiv
with respect to CuCN), which was taken up in 17 min. After
10 min at -78 °C, the resulting bright yellow solution was
placed in a bath at -50 °C. The reaction was left for 1 h under
a positive acetylene atmosphere and then for 40 min in the
absence of acetylene. The solution was recooled to -78 °C and
treated rapidly with cyclohexenone (300 mg, 3.12 mmol)
followed immediately by Et3SiCl (940 mg, 6.24 mmol). After
15 min the reaction was complete by TLC. After a further 15
min the solution was poured into a mixture of ice-cold Et2O:
1:4 NH4OH/NH4Cl. The mixture was stirred at rt for 15 min.
The resulting deep blue mixture was extracted with ether and
1
listed relative to CHCl3 (δ 7.24) for H NMR and CDCl3 (δ 77.0)
for 13C NMR. All tin coupling constants refer to Sn-H
coupling constants (J Sn-H) and, unless otherwise indicated, are
given as an average of the 117Sn and 119Sn values. Where
necessary, COSY and HETCOR were performed to allow
complete peak assignment. Infrared spectra were obtained on
an FTIR spectrophotometer. It should be noted that Me3SnH
is a highly volatile toxic liquid. The Lipshutz procedure for
its preparation and handling is recommended (see refs 1 and
13c). In general, all trimethyltin compounds are potentially
toxic and should be handled with care (ref 1).
Typ ica l Exp er im en ta l P r oced u r e Usin g Tr ieth ylsilyl
Ch lor id e (P r oced u r e A). To diisopropylamine (freshly
distilled, 1.48 mL, 11.3 mmol, 1.2 equiv) in dry THF (5 mL),
at -78 °C under argon, was added nBuLi (2.4 M) in hexanes
(600 mg, 3.89 mL, 9.36 mmol). After 30 min the near-colorless
solution was transferred via cannula to a cold (-78 °C) solution
of CuCN (402 mg, 4.68 mmol) and lithium chloride (396 mg,

(Trimethylstannyl)vinyl Cuprates
J . Org. Chem., Vol. 61, No. 16, 1996 5411
purified either by Kugelrhor distillation (ca. 110 °C at 0.5 mm)
or by flash column chromatography using (pentane + 1% Et3N)
to afford 6 (1.1 g, 89%) as a clear colorless oil.
1-[(Tr ieth ylsilyl)oxy]-3-bu tyl-4, 4-d im eth ylcycloh ex-1-
1
en e (en tr y 7, Ta ble 1): IR (film) 1688, 1198 cm-1; H NMR
(200 MHz, CDCl3) 0.4-0.8 (m, 9H), 0.8-1.1 (m, 21H), 1.2-
1.5 (m, 4H), 1.9-2.1 (m, 1H), 4.8 (bs, 1H); 13C NMR (50 MHz,
CDCl3) 5.90, 7.56, 14.87, 22.17, 23.61, 27.97, 29.02, 30.72,
31.02, 32.11, 37.03, 44.63, 106.83, 148.32; MS (EI) 296 (M+,
10), 239 (M - C4H9, 69), 183 (100), 155 (30), 111 (17); HRMS
(EI) calcd for C18H36OSi 296.2535, found 296.2530.
Typ ica l Exp er im en ta l P r oced u r e Usin g Bis(tr im eth -
ylsilyl)a ceta m id e BSA (P r oced u r e B). The bright yellow
solution of cuprate 9 (3.36 mmol), generated as described
above, was recooled to -78 °C and treated rapidly with BSA
(1.11 mL, 4.48 mmol), followed by a solution of keto ester 18
(700 mg, 2.24 mmol) in dry THF (3 mL). After 15 min, TLC
(hexane: CH2Cl2:EtOAc ) 10:2:1) indicated complete reaction.
After a further 15 min the solution was poured into a mixture
of ice-cold Et2O:1:4 NH4OH /NH4Cl. The mixture was stirred
at ambient temperature for 15 min. The resulting deep blue
mixture was extracted with ether and purified by flash column
chromatography using (hexane:CH2Cl2:EtOAc ) 10:2:1 + 1%
Et3N) to afford 28 as a wax (1.03 g, 92%).
Tr ieth yl 4-[(tr ieth ylsilyl)oxy]-2-bu tylcycloh ex-3-en e-
1,1,3-tr ica r boxyla te (19): IR (film) 2937-1736, 1716, 1640
1
cm-1; H NMR (200 MHz, CDCl3), 0.62 (q, J ) 8.0 Hz, 2H),
0.81 (m, 3H), 0.91 (t, J ) 8.0 Hz, 3H), 1.15-1.32 (m, 15H),
2.12-2.40 (m, 4H), 3.52 (collapsed t, 1H), 4.05-4.38 (m, 6H);
13C NMR (50 MHz, CDCl3) 7.16, 8.38, 15.63, 16.06, 24.35,
24.62, 30.09, 31.22, 35.14, 39.46, 58.48, 60.97, 62.47, 113.97,
155.95, 167.09, 167.80, 170.38; MS (CI, NH3) 485 (M+, 0.3),
455 (M - C2H5, 0.5), 397 (M - C6H15, 1), 371 (28), 325 (61),
The following compounds described in Table 1 were isolated
in the course of addition of mixed cuprates 4 to cyclohex-2-
enones.
-
313 (M + H - C8H12O4, 100); MS (EI) 455 (M+ C2H5, 0.5),
397 (1), 370 (7), 313 (100); HRMS (EI) calcd for C19H30O7Si -
C2H5 455.2483, found 455.2465.
1-[(Tr ieth ylsilyl)oxy]-3-(tr im eth ylsta n n yl)cycloh ex-1-
The following compounds were prepared using procedure A.
1-[(Tr ieth ylsilyl)oxy]-3-[2(Z)-(tr im eth ylsta n n yl)eth en -
1
en e (5): IR (film) 1653 cm-1; H NMR (200 MHz, CDCl3) 0.6
2
(s, 9H, J Sn-H ) 51.0 Hz), 0.67 (q, J ) 8.0 Hz, 6H), 0.95 (t, J
yl]cycloh ex-1-en e (6): IR (film) 1659, 1197, 765 cm-1
;
1H
) 8.0 Hz, 9H), 1.55-1.75 (m, 2H), 1.78-2.20 (m, 4H), 5.0 (d,
2
2
119
117
2
NMR (270 MHz, CDCl3) 0.04 (s, 9H, J Sn ) 54.0 Hz, J Sn
) 51.3 Hz), 0.63 (q, J ) 12.0 Hz, 6H),) 0.95 (t, J ) 12.0 Hz,
9H), 1.18-1.32 ( m, 1H), 1.48-1.82 (m, 3H), 1.95-2.05 (m,
2H), 2.59-2.62 (m, 1H), 4.65 (dd, J ) 2.0, 4.0 Hz, 1H), 5.73
J ) 4.0 Hz, 1H, J Sn-H ) 24.8 Hz); 13C NMR (50 MHz, CDCl3)
-9.56, 5.95, 7.60, 24.11, 24.35, 26.85, 30.39, 107.65, 146.38;
MS (EI) (M+ + 1, 0.4) 361 (M - CH3, 2.3), 211(M - C3H9Sn,
100), 115 (M - C9H17OSn, 35); HRMS calcd for C15H32OSiSn
- C3H9Sn 211.1518, found 211.1521.
2
2
119
117
(d, J ) 12 Hz, 1H, J Sn ) 83.7 Hz, J Sn ) 78.3 Hz), 6.23
3
3
119
117
(dd, J ) 10.0, 12.0 Hz, 1H, J Sn
) 153.9 Hz, J Sn
)
trans
trans
1-[(Tr ieth ylsilyl)oxy]-3-m eth ylcycloh ex-1-en e (7) (R )
147.6 Hz); 13C NMR (68 MHz, CDCl3) -8.34, 5.06, 6.70, 21.60,
29.40, 29.56, 42.89, 101.17, 127.49, 151.29, 153.58; MS (EI)
401 (M - 1, 3), 387 (M - CH3, 19), 237 (M - C3H9Sn, 100),
211 (56), 165 (33), 115 (49); HRMS calcd for C17H34OSnSi -
CH3 387.1166, found 387.1169.
Me): IR (film) 2954, 2933, 1664 cm-1 1H NMR (200 MHz,
;
CDCl3) 0.63 (q, J ) 8.0 Hz, 6H), 0.92-1.40 (m, 15H), 1.42-
1.85 (m, 4H), 1.95-2.06 (m, 2H), 2.15-2.32 (m, 1H), 4.75 (s,
1H); 13C NMR (50 MHz, CDCl3) 5.95, 7.56, 22.48, 23.13, 30.08,
30.33, 31.70, 110.37, 148.80; MS (EI) 226 (M+, 29), 211 (M -
1-[(Tr ieth ylsilyl)oxy]-3-[2(Z)-(tr im eth ylstan n yl)eth en yl]-
4,4-dim eth yl cycloh ex-1-en e (en tr y 10, Table 1): IR (CDCl3)
CH3, 100), 197 (37), 115 (24), 103 (49); HRMS calcd for C13H26
OSi 226.1753, found 226.1756.
-
1238, 1366, 1661 cm-1
;
1H NMR (270 MHz, CDCl3) 0.14 (s,
1-[(Tr ieth ylsilyl)oxy]-3-p h en ylcycloh ex-1-en e (7) (R )
P h ): IR (film) 1661, 1651, 849, 737 cm-1; 1H (200 MHz, CDCl3)
0.58 (q, J ) 8.0 Hz, 6H), 0.96 (t, J ) 8.0 Hz, 9H), 2.52 (ddd, J
) 5.0, 13.0, 19.8 Hz, 2H), 2.27 (bs, 1H), 2.40-2.55 (m, 2H),
2.70-2.78 (m, 2H), 6.39 (s, 1H), 7.32-7.38 (m, 3H), 7.45-7.53
(m, 2H); 13C NMR (50 MHz, CDCl3) 6.59, 7.36, 23.35, 28.59,
37.60, 46.25, 124.69, 125.39, 128.03, 129.26, 137.93, 158.86;
MS (EI) 172 (M - H - C6H15Si, 68) 144 (M - C10H8O, 100),
115 (49); HRMS calcd for C18H28OSi - H - C6H15Si 172.0888,
found 172.0886.
1-[(Tr iet h ylsilyl)oxy]-3-(1,1-d im et h ylet h yl)cycloh ex-
en e (7) (R ) tBu ): IR (film) 2957, 1669, 1653 cm-1; 1H NMR
(200 MHz, CDCl3) 0.58 (q, J ) 8.0 Hz, 6H), 0.88 (t, J ) 8.0
Hz, 9 H), 1.11 (s, 9H), 1.88 (m, 2H), 2.30-2.39 (m, 4H), 5.94
(bs, 1H); 13C NMR (50 MHz, CDCl3) 7.55, 8.33, 24.85, 27.43,
2
2
119
117
9H, J Sn ) 54.0 Hz, J Sn ) 51.0 Hz),), 0.64 (q, J ) 7.0 Hz,
6H), 0.82 (s, 3H), 0.93, 0.96 (2 × t, J ) 7.0 Hz, 9H), 1.31-1.38
and 1.47-1.54 (m, 2H), 1.9-2.04 (m, 2H), 2.25-2.30 (m, 1H),
4.53 (bs, 1H), 5.75 (d, J ) 12.1 Hz, 1H, 2J Sn ) 83.7 Hz, J Sn
2
119
117
2
119
) 79.7 Hz), 6.23 (dd, J ) 9.9, 12.0 Hz, 1H, J Sn
) 156.7
trans
2
Hz, J Sn
) 149.2 Hz); 13C NMR (68 MHz, CDCl3) -8.26,
117
trans
5.06, 6.71, 24.47, 27.45, 28.07, 31.22, 34.92, 106.7, 128.49,
149.79, 150.3; MS (CI, NH3) 429 (M+, 12), 415 (M - CH3, 60),
265 (M - C3H9Sn, 73), 239 (M - C5H11Sn, 100), 209 (78);
HRMS (EI) calcd for C19H38OSiSn - CH3 415.1479, found
415.1493.
Dieth yl 4-[(tr ieth ylsilyl)oxy]-2-[2(Z)-(tr im eth ylstan n yl)-
eth en yl]cycloh exen -3-en e-1,1- d ica r boxyla te (en tr y 11,
Ta ble 1): IR (film) 1738, 1668 cm-1 1H NMR (270 MHz,
;
CDCl3) 0.18 (s, 9H), 0.59 (q, J ) 10.8 Hz, 6H), 0.92 (t, J )
10.0 Hz, 9H), 1.14, 1.21 (2 × t, J ) 9 Hz, 6H), 1.9-2.32 (m,
4H), 3.50 (dd, J ) 4.6, 10.0 Hz, 1H), 3.9-4.2 (m, 1H), 4.08-
4.21 (m, 3H), 4.64 (d, J ) 4.6 Hz, 1H), 5.78 (d, J ) 11.9 Hz,
29.73, 38.16, 38.85, 123.35, 173.61; MS (CI) 153 (M - C6H15
Si, 100), 124 (M - H - C8H19Si, 32); HRMS calcd for C16H32
OSi - C6H15Si 153.1279, found 153.1275.
-
-
1H, 2J Sn-H 73.5 Hz), 6.19 (dd, J ) 10.0, 11.9 Hz, 1H, 3J Sn
The following compounds were prepared by addition of
cuprate 4d to cyclohex-2-enones and keto esters.
119
trans
) 148.5 Hz, 3J Sn
) 139.1 Hz); 13C NMR (68 MHz, CDCl3)
117
trans
1-[(Tr ieth ylsilyl)oxy]-3-bu tylcycloh exen e (7) (R ) n Bu ):
-8.48, 4.93, 6.63, 14.06, 24.41, 26.68, 45.07, 56.22, 61.2, 61.33,
105.75, 130.70, 146.26, 149.33, 170.06, 170.45; MS (EI) 546
(M+, 1), 531 (M - CH3, 18), 381 (M - C3H9Sn, 100), 355 (M -
C5H11Sn, 22), 165 (M - C20H33O5Si, 19); HRMS calcd for
C23H42O5SiSn - CH3 531.1588, found 531.1568.
Meth yl (E)-3-(Tr im eth ylstan n yl)bu t-2-en oate (13) (Con -
ta in s ca . 10% Im p u r ity). To a solution of the cuprate 9 (2.38
mmol) prepared as outlined above was added methyl 2-bu-
tynoate (12) (200 mg, 2.04 mmol). The resulting pale red
solution was stirred for 0.5 h and then worked up as above.
Chromatographic purification over silica gel using (hexane:
CH2Cl2:EtOAc ) 20:2:1) as eluent provided the title compound
(497 mg, 92%) as a pale yellow oil: IR (film) 2918, 1733, 1706
IR (film) 1664, 1189, 744 cm-1 1H NMR (500 MHz, CDCl3)
;
0.65 (q, J ) 8.0 Hz, 6H), 0.88 (m, 3H), 0.96, 0.91 (2 × t, J )
8.0 Hz, 9H), 1.7 (bq, J ) 7.0 Hz, 2H), 1.21-1.32 (bs, 5H), 1.48-
1.50 (m, 1H), 1.65-1.79 (m, 2H), 1.92-2.20 (m, 2H), 2.06-
2.12 (m, 1H), 4.81 (bd, J ) 2.0 Hz, 1H); 13C NMR (125 MHz,
CDCl3) 4.90, 6.53, 13.94, 21.69, 22.77, 28.77, 29.09, 29.83,
34.42, 36.58, 109.2, 150.12; MS (EI) 268 (M+, 6), 239 (M -
C2H5, 4), 211 (M - C4H9, 100); HRMS calcd for C16H32OSi
268.2222, found 268.2228
3-[(2(Z)-(T r im e t h ylst a n n y l)e t h e n y l]c yc lo h e xa n -1-
on e (en tr y 5, Ta ble 1; 30, Ta ble 2): IR (film) 1725 cm-1; 1H
2
NMR (200 MHz, CDCl3) 0.15 (s, 9H, J Sn-H ) 58.0 Hz), 1.49-
2
1
2
1.88 (m, 3H), 2.01-2.41 (m, 5H), 5.81 (d, J ) 12.5 Hz, J Sn
cm-1; H NMR (200 MHz, CDCl3) 0.17 (s, 3H, J Sn-H ) 56.5
119
2
3
117
) 75.2 Hz, J Sn ) 71.6 Hz), 6.3 (dd, J ) 8.4, 12.5 Hz, 1H);
13C NMR (50 MHz, CDCl3) -7.51, 25.82, 32.29, 41.45, 46.95,
48.14, 128.81, 150.09, 208.92; MS (EI) 288 (M+, 1), 273 (M -
CH3, 100), 165 (M - C8H11O, 29), 151 (37); HRMS calcd for
C11H20OSn 288.0536, found 288.0538.
Hz), 2.15 (s, 3H), 3.71 (s, 3H), 6.40 (bs, 1H, J Sn-H ) 115.0
cis
Hz); 13C NMR (50 MHz, CDCl3) 6.83, 27.50, 51.67, 51.97,
129.98, 170.63; MS (EI) 263 (M+ - 1, 28), 165 (M - C5H7O2,
100), 135 (44); HRMS calcd for C8H16O2Sn - H 263.0094 found,
263.0088.

5412 J . Org. Chem., Vol. 61, No. 16, 1996
Pereira and Chan
1-[(Tr ieth ylsilyl)oxy]cycloh exa -1,3-d ien e (14). To a
solution of diisopropylamine (DIPA) (1.02 mL, 789 mg, 7.8
mmol) in dry THF (8 mL) at -78 °C, under argon, was added
nBuLi (7.8 mmol). After 30 min, the solution was added to a
cold (-78 °C) solution of CuCN (349 mg, 3.9 mmol, 1.5 equiv)
and LiCl (330 mg, 7.8 mmol) in dry THF (18 mL). The
resulting mauve/blue solution was stirred for 30 min and then
treated with Et3SiCl (540 µL, 391 mg, 2.6 mmol, 2 equiv)
followed immediately by cyclohex-2-enone (0.252 mL, 250 mg,
2.6 mmol). After 1 h the reaction was almost complete by TLC
analysis. The reaction was left for a further 15 min and then
worked up as described above to afford an opaque pale green
oil (1.14 g). The oil was applied to column of silica (50 g) and
flash-eluted with pentane:1% Et3N as solvent to give a clear
oil (468 mg) that was repurified (using the same eluent) over
silica to give the diene 14 (328 mg, 60%) as a clear colorless
Hz, 2H), 7.44 (d, J ) 8.6 Hz, 2H), 7.70 (s, 1H); 13C NMR (68
MHz, CDCl3) 27.90, 28.90, 35.20, 55.5, 57.1, 66.90, 83.90,
114.10, 128.0, 130.10, 150.10, 160.0, 164.10, 166.90, 193.0; MS
(EI) 460 (M+, 0.4), 404 (M + H - C4H9, 0.1), 348 (2), 212 (14),
137 (M - C17H23O6, 47), 121 (M - C17H23O7, 100); HRMS calcd
for C25H32O8 460.2097, found 460.2101.
Bis(1,1-d im eth yleth yl) p-m eth oxyben zyl 4-[(tr ieth yl-
silyl)oxy]cycloh ex-3-en e-1,1,3-tr icar boxylate (25): IR (film)
1727, 1717, 1683 cm-1; 1H NMR (270 MHz, CDCl3), 0.60 (q, J
) 8.0 Hz, 6H), 0.91 (t, J ) 8.0 Hz, 9H), 1.42 (s, 18H), 2.04
(collapsed dd, J ) 5.4 Hz, 2H), 2.22 (collapsed dd, J ) 5.4 Hz,
2H), 2.76 (bs, 2H), 3.78 (s, 3H), 5.09 (s, 2H), 6.84 (d, J ) 8.1
Hz, 2H), 7.29 (d, J ) 8.1 Hz, 2H); 13C NMR (68 MHz, CDCl3)
5.45, 6.69, 27.42, 27.87, 29.39, 30.53, 53.86, 55.34, 65.38, 81.34,
106.15, 113.78, 129.03, 130.11, 158.72, 159.43, 166.63, 170.19;
MS (CI, NH3) 577 (M + 1, 0.1), 503 (M - C4H9O, 1) 455 (M -
C8H9O, 4), 299 (10) 121 (M - C23H38O7Si, 100); HRMS (CI)
calcd for C31H48O8Si - C4H9O 503.2465, found 503.2437
oil: IR (film) 1664, 1646, 1586 cm-1 1H NMR (200 MHz,
;
CDCl3) 0.71 (q, J ) 10.0 Hz, 6H), 0.98 (t, J ) 10.0 Hz, 9H),
2.21-2.31 (m, 4H), 5.12 (d, J ) 6.0 Hz, 1H), 5.42 (m, 1H), 5.81
(m, 1H); 13C NMR (50 MHz, CDCl3) 6.75, 8.37, 25.51, 30.09,
102.40, 118.54, 124.90, 153.84; MS (EI) 210 (M+, 100), 179 (42),
151 (M - 1 - C4H10, 47), 115 (M - C6H7O, 28), 87 (58); HRMS
calcd for C12H22OSi 210.1440 found, 210.1442.
Tr ieth yl 4-Oxo-2-cya n ocycloh exa n e-1,1,3-tr ica r boxy-
la te (26). A solution of the cuprate 9 (0.38 mmol) generated
as described in procedure A was recooled to -78 °C and treated
with TMSCN (69 µL, 52 mg, 0.52 mmol, 2 equiv with respect
to enone ester) followed by a solution of keto ester 18 (80 mg,
0.26 mmol) in dry THF (0.2 mL) added rapidly. The bright
yellow color was retained, and after 15 min TLC indicated
complete reaction. The reaction was left a further 0.5 h and
then worked up in the usual way to give an orange oil (180
mg). Flash chromatographic purification of the oil on silica
(10 g) using (hexane:CH2Cl2:EtOAc ) 10:2:1) as eluent pro-
vided the title compound 26 (57 mg, 65%) as a pale brown wax:
Tr ieth yl 4-[(tr ieth ylsilyl)oxy]-2-[2(Z)-(tr im eth ylsta n -
n yl)eth en yl]cycloh ex-3-en e-1,1,3-tr ica r boxyla te (20): IR
(film) 1738, 1722, 1693 cm-1; 1H NMR (270 MHz, CDCl3) 0.22
2
(s, 9H, J Sn-H ) 54.0 Hz), 0.58 (q, J ) 7.5 Hz, 6H), 0.94 and
0.92 (2 × q, J ) 7.5 Hz), 1.19-1.25 (2 × t, J ) 7.3 Hz, 9H),
2
119
2.0-2.4 (m, 4H), 3.9-4.3 (m, 6H), 5.83 (d, J ) 12.5 Hz, J Sn
3
) 67.0, 2J Sn ) 64.8 Hz), 6.20 (dd, J ) 10.3, 12.5 Hz, J Sn
117
119
trans
) 148.5 Hz, 3J Sn
) 141.8 Hz); 13C NMR (68 MHz, CDCl3)
117
1
IR (film) 2222, 1741, 1686 cm-1; H NMR (270 MHz, CDCl3)
trans
-7.87, 5.76, 6.70, 13.95, 13.99, 14.63, 21.92, 26.09, 41.99, 57.99,
60.6, 61.45, 61.61, 99.44, 132.80, 145,03, 169.54, 169.65,
170.61, 171.92; MS (EI) 603 (M+ - CH3,19), 453 (M - C3H5-
Sn, 9), 250 (8), 208 (14), 193 (100); HRMS (EI) calcd for
C26H46O7SiSn - CH3 603.1796, found 603.1825.
1.21, 1.36, 1.39 (3 × t, J ) 8.1 Hz, 9H), 2.2-2.7 (m, 4H), 4.15
(m, 6H), 4.49 (s, 1H), 12.42 (s, 1H); 13C NMR (68 MHz, CDCl3)
13.91, 13.96, 14.14, 23.39, 25.96, 30.67, 55.59, 62.70, 62.91,
93.67, 118.36, 166.96, 167.40, 170.07, 173.07; MS (EI) 339 (M+,
43), 294 (M - C2H5O, 32) 265 (M - H - C3H5O2, 100); HRMS
calcd for C16H21O7N 339.1318, found 339.1315.
Tr ieth yl 4-[(tr ieth ylsilyl)oxy)]cycloh ex-3-en e-1,1,3-tr i-
1
ca r boxyla te (21): IR (film) 1735, 1654, 1648 cm-1; H (200
The following compounds were prepared using procedure B.
MHz, CDCl3) 0.6 (q, J ) 10.0 Hz, 6H), 0.98 (t, J ) 8.4 Hz,
Tr ieth yl 4-oxo-2-[(2(Z)-(tr im eth ylsta n n yl)eth en yl]cy-
cloh exa n e-1,1,3-tr ica r boxyla te (28): IR (film) 1749, 1738,
1651, 1646 cm-1; 1H NMR (270 MHz, CDCl3) 0.22 (s, 9H, 2J Sn-H
) 51.3 Hz), 1.19, 1.28 (2 × t, J ) 6.0 Hz, 9H), 2.2-2.42 (m,
4H), 3.90-4.04 (m, 2H), 4.02 (d, J ) 10 Hz, 1H), 4.13-4.29
9H), 1.25, 1.28 (2 × t, J ) 6.0 Hz, 9H), 2.15-2.25 (m, 2H),
2.35-2.41 (m, 2H), 2.79 (bs, 2H), 4.20 (q, J ) 6.0 Hz, 6H); 13
C
NMR (68 MHz, CDCl3) 5.76 6.53, 13.96, 14.22, 26.03, 26.60,
27.83, 52.93, 60.52, 61.58, 95.21, 170.12, 170.79, 171.92; MS
(EI) 315 (M + 2, 100), 314 (M + H - C6H15Si, 36), 313 (M -
2
2
119
117
-
(m, 4H), 5.83 (d, J ) 12.5 Hz, 1H, J Sn ) 71.5 Hz, J Sn
)
C6H15Si, 3), 269 (31), 241 (M C9H20O2Si, 19), 196 (61), 195
67.8 Hz), 6.1 (dd, J ) 10.0, 12.5 Hz, 1H, 3J Sn trans ) 151.2 Hz,
119
(59), 167 (M - C12H25O4Si, 100); HRMS calcd for C21H36O7Si
3
J Sn
) 145.8 Hz), 12.5 (s, 1H); 13C NMR (68MHz, CDCl3)
117
trans
+ H - C6H15Si 314.1365, found 314.1361.
-7.85, 13.98, 14.66, 21.94, 26.12, 41.73, 58.01, 60.60, 61.6,
99.46, 132.82, 145.07, 169.54, 170.62, 171.94; MS (EI) 489 (M+
- CH3, 19), 443 (9), 205 (M - 2 - C11H18O3Sn, 100), 165 (M -
C17H23O7, 55), 149 (45), 103 (73); HRMS (EI) calcd for C20H32O7-
Sn - CH3 489.0935, found 489.0942.
Eth yl 2-oxo-6-[2(Z)-(tr im eth ylsta n n yl)eth en yl]cyclo-
h exa n eca r boxyla te (23): IR (film) 1749, 1720, 1651 cm-1
;
2
1H NMR (500 MHz, CDCl3) 0.18, 0.19 (2 × s, 18H, J Sn-H
)
52.5 Hz), 1.24 (t, J ) 7.0 Hz, 6H), 1.54-1.86 (m, 7H), 2.12-
2.58 (m, 1H), 2.25 (collapsed dd, 4H), 2.42 (d, J ) 15.0 Hz,
2H), 2.76 (td, J ) 5.0, 9.2 Hz, J ) 15.0 Hz, 1H), 3.05 (td, J )
2.5, 9.2, 10.0 Hz, 1H), 3.28 (d, J ) 11.0 Hz, 1H), 4.16, 4.2 (2 ×
t, J ) 7.0 Hz, 6H), 5.76 (d, J ) 12.5 Hz, 1H, 2J Sn-H ) 72.0 Hz),
Bis(1,1-dim eth yleth yl) p-m eth oxyben zyl) 4-oxo-2-[2(Z)-
(tr im eth ylsta n n yl)eth en yl] cycloh exa n e-1,1,3-tr ica r box-
yla te (29): IR (smear) 3750-3000, 1741, 1732, 1717, 1653,
1
2
1645 cm-1; H NMR (270 MHz, CDCl3) 0.38 (s, 9H, J Sn-H
)
2
5.88 (d, J ) 12.2 Hz, 1H, J Sn-H ) 70.0 Hz), 6.26 (dd, J ) 9.3,
12.2 Hz, 1H), 6.26 (dd, J ) 9.3 Hz, J ) 12.2 Hz, 1H, 3J Sn
119
54.0 Hz)), 1.47 (s, 9H), 1.97-2.39 (m, 4H), 3.77 (s, 3H), 3.99
(d, J ) 10.0 Hz, 1H), 5.01 (d, J ) 12.1 Hz, 1H), 5.33 (d, J )
12.0 Hz, 2H), 5.88 (d, J ) 12.5 Hz, 1H, 2J Sn-H ) 55.0 Hz), 6.13
trans
) 141.0 Hz, 3J Sn ) 136.0 Hz), 6.40 (dd, J ) 9.3, 12.3 Hz, 1H,
117
3
3
119
117
J Sn
) 157.5 Hz, J Sn
) 150.0 Hz), 12.57 (s, 1H);
trans
trans
(dd, J ) 12.0 Hz, 1H, 3J Sn
) 153.9 Hz, 3J Sn
) 145.8
119
117
13C NMR (125 MHz, CDCl3) -8.40, -8.43, 14.23, 14.53, 18.13,
24.86, 29.29, 31.33, 31.61, 38.94, 40.81, 48.29, 60.18, 60.85,
62.73, 100.77, 127.70, 131.72, 148.42, 153.65, 168.86, 172.81,
173.09, 205.10; MS (EI) 345 (M+ - CH3, 100), 299 (M - 1 -
C3H8O, 50), 269 (45), 165 (M + H - C12H18O3, 45); HRMS calcd
for C14H24O3Sn - CH3 345.0513, found 345.0526.
trans
trans
Hz), 6.85 (d, J ) 8.0 Hz, 2H), 7.27 (d, J ) 8.0 Hz, 2H), 12.29
(s, 1H); 13C NMR (68 MHz, CDCl3) -7.49, 22.57, 26.39, 27.68,
27.81, 41.58, 55.25, 58.66, 65.81, 81.53, 81.75, 99.62, 113.86,
128.33, 129.72, 132.77, 145.05, 159.48, 168.86, 171.24, 171.57;
MS (EI) 637 (M+ - CH3, 1), 185 (11), 165 (M - C27H35O8, 10),
121 (M - C22H35O7Sn, 100), 84 (99); HRMS calcd for C30H44O8-
Sn - CH3 637.1823, found 637.1847.
Bis(1,1-d im eth yleth yl) p-Meth oxyben zyl 4-Oxocyclo-
h ex-2-en e-1,1,3-tr ica r boxyla te (24) (See Ref 19). A vigor-
ously stirred solution of the selenide 34 (300 mg, 0.485 mmol)
in CH2Cl2 (2 mL) and water (0.2 mL) at 0 °C was treated with
30% hydrogen peroxide (0.163 mL, 1.45 mmol, 3 equiv) in
water (0.5 mL). The reaction was complete in 15 min. The
solution was diluted and then washed sequentially with
NaHCO3, water, and brine. Drying and removal of solvent
3-[2(Z)-(Tr im et h ylst a n n yl)et h en yl]cycloh exa n -1-on e
1
(30): IR (film) 2970, 1710 cm-1; H NMR (200 MHz, CDCl3)
2
0.15 (s, 9H, J Sn-H ) 58.0 Hz), 1.49-1.88 (m, 3H), 2.01-2.41
2
2
119
117
(m, 5H), 5.81 (d, J ) 12.5 Hz, J Sn ) 75.4 Hz, J Sn ) 71.4
Hz), 6.3 (dd, J ) 8.4, 12.5 Hz, 1H, 3J Sn trans ) 146.0 Hz, 3J Sn
119
117
) 138.8 Hz); 13C NMR (50 MHz, CDCl3) -7.51, 25.82,
trans
gave a colorless gum (114 mg, 51%): IR (film) 1732, 1669 cm-1
;
32.29, 41.45, 46.95, 48.14, 128.81, 150.09, 208.92; MS (EI) 288
(M+, 1), 273 (M - CH3, 100), 165 (M - C8H11O, 29), 151 (37);
HRMS calcd for C11H20OSn 288.0536, found 288.0538.
1H NMR (270 MHz, CDCl3) 1.56 (s, 18H), 2.5-2.58 (m, 2H),
2.68-2.74 (m, 2H), 3.90 (s, 3H), 5.30 (s, 2H), 6.98 (d, J ) 8.6

(Trimethylstannyl)vinyl Cuprates
J . Org. Chem., Vol. 61, No. 16, 1996 5413
3-[2(Z)-(Tr im eth ylsta n n yl)eth en yl]-4,4-d im eth ylcyclo-
(d, J ) 9.0 Hz, 2H), 12.3 (s, 1H); 13C NMR (68 MHz, CDCl3)
26.17, 16.66, 27.72, 27.80, 53.99, 55.27, 65.79, 81.49, 95.34,
113.88, 128.09, 129.85, 130.23, 170.04, 170.74, 171.84; MS (EI)
462 (M+, 0.4), 406 (M - C4H10, 0.8), 137 (M - C17H25O6, 13),
121 (M - C17H25O7, 100); HRMS calcd for C25H34O8 462.2253,
found 462.2249.
1
h exa n -1-on e (31): IR (film) 2940, 1717 cm-1; H NMR (270
2
MHz, CDCl3) 0.12 (s, 9H, J Sn-H ) 64.8 Hz), 0.98 (s, 3H), 1.08
(s, 3H), 1.50-1.80 (m, 2H), 2.02-2.48 (m, 4H), 5.86 (d, J )
2
2
119
117
12.5 Hz, 1H, J Sn ) 78.3 Hz, J Sn ) 74.2 Hz), 6.3 (dd, J )
3
3
119
117
10.0, 12.5 Hz, J Sn
) 125.6 Hz, J Sn
) 119.6 Hz);
trans
trans
13C NMR (125 MHz, CDCl3) -8.31, 20.48, 29.02, 38.18, 39.90,
44.36, 54.44, 131.40, 147.83, 210.5; MS (EI) 316 (M+, 0.8), 301
(M - CH3, 100), 165 (M - C10H14O, 54), 151 (M - C3H9Sn,
31); HRMS calcd for C13H24OSn - CH3 301.0614, found
301.0616.
Bis(1,1-dim eth yleth yl) p-Meth oxyben zyl 4-Oxo-3-(ph en -
ylselen yl)cycloh exa n e-1,1,3-tr ica r boxyla te (34). A solu-
tion of PhSeCl (683 mg, 3.56 mmol, 1.05 equiv) in dry CH2Cl2
(28 mL) at 0 °C under argon was treated with dry pyridine
(287 µL, 281 mg, 3.56 mmol, 1.1 equiv). After 15 min a
solution of the triester 33 (1.5 g, 3.24 mmol) in CH2Cl2 (5 mL)
was added dropwise over 5 min. The initial brown solution
gradually lightened to a bright yellow. Reaction was 90%
complete in 1 h at 0 °C with no further change after 4 h. The
solution was allowed to warm to ambient temperature over
15 min and then washed with 2 N HCl (10 mL), saturated
NaHCO3 (10 mL), and brine. Drying and evaporation of the
organic phase afforded an oil (1.7 g). Flash chromatography
using hexanes:CH2Cl2:EtOAc 20:2:1 as eluent provided the title
selenide as a low-melting solid (1.22 g, 61%): IR (smear) 1726,
1661, 1614 cm-1; 1H NMR (270 MHz, CDCl3), 1.40 (s, 9H), 1.46
(s, 9H), 1.95 to 2.09 (m, 1H), 2.30 to 2.60 (m, 2H), 2.71 (d, J )
16.2 Hz, 2.80-2.95 (m, 1H), 2.92 (d, J ) 16.4 Hz, 1H), 3.8 (s,
3H), 4.8 (d, J ) 12.0 Hz, 1H), 5.20 (d, J ) 12.0 Hz, 1H), 6.86
(d, J ) 8.6 Hz, 2H), 7.2-7.4 (m, 5H), 7.5 (d, J ) 9.0 Hz, 2H);
13C NMR (68 MHz, CDCl3) 27.7, 27.76, 30.11, 36.26, 39.47,
53.69, 55.28, 59.21, 67.35, 82.06, 82.16, 113.81, 126.01, 127.21,
128.62, 129.45, 130.18, 138.38, 168.30, 169.42, 169.59, 203.01;
MS (EI) 618 (M+, 0.4), 462 (M + H - C6H5Se, 0.2), 406 (M +
2 - C10H14Se, 0.4), 137 (M - C23H29O6Se, 9.5), 121 (M -
C23H29O7Se, 100); HRMS calcd for C31H38O8Se 618.1731, found
618.1727.
p-Meth oxyben zyl Acr yla te (32) (See Ref 19). To a
solution of p-methoxybenzyl alcohol (2.0 g, 0.014 mol) in dry
THF (30 mL, 0.5 M) at 40 °C, under argon, was added sodium
hydride (60% dispersion, 590 mg, 0.015 mol, 1.05 equiv).
Vigorous effervescence ensued as the temperature climbed to
ca. 48 °C. After 15 min the opaque mixture was cooled to -78
°C and treated with a solution of acryloyl chloride (1.9 g, .021
mol, 1.5 equiv) in dry THF (10 mL). After 2 h at -78 °C TLC
showed complete reaction. The mixture was diluted with ethyl
acetate (60 mL) and washed with 2 N HCl, saturated NaHCO3,
water, and brine. The organic layer was dried and evaporated
to an oil (2.79 g), which was applied to a column of silica gel
(100g) and flash chromatographed using hexanes: CH2Cl2:
EtOAc 20:2:1 as eluent to provide the title compound as a
colorless oil (1.68 g, 93%): IR (film) 1728 cm-1; 1H NMR (200
MHz, CDCl3) 3.81 (s, 3H), 5.81 (s, 2H), 5.84 (dd, J ) 2.4, 10.3
Hz, 1H), 6.15 (dd, J ) 10.2, 17.3 Hz, 1H), 6.4 (d, J ) 17.2 Hz,
1H), 6.90 (d, J ) 8.4 Hz, 2H), 7.34 (d, J ) 8.4 Hz, 2H); 13C
NMR (68 MHz, CDCl3) 55.27, 66.13, 113.94, 127.97, 128.43,
130.1, 159.66, 166.08; MS (EI) 192 (M+, 65), 121 (M - C3H3O2,
100); HRMS calcd for C11H12O3 192.0786, found 192.0787.
Bis(1,1-d im eth yleth yl) p-Meth oxyben zyl 4-Oxocyclo-
h exa n e-1,1,3-tr ica r boxyla te (33). To a warm (40-45 °C)
suspension of NaH (30 mg, 1.25 mmol, 2.5 equiv) in dry THF
(200 µL) under argon was added di-tert-butyl malonate (106
µL, 0.478 mmol). Following complete evolution of hydrogen,
a solution of p-methoxybenzyl acrylate 32 (100 mg, 0.502
mmol) in dry THF (100 µL) was added dropwise, over 20 min.
Reaction was complete in 40 min. The dirty yellow solution
was diluted with CH2Cl2 (10 mL) and washed with 2 N HCl,
water, and brine. The extract was dried and evaporated to a
wax (298 mg). Flash chromatography over silica gel (30 g)
using hexanes:CH2Cl2:EtOAc 10:2:1 as eluent afforded the title
compound as a colorless solid (167 mg, 81%): IR (smear) 2940,
1717 cm-1; 1H NMR (270 MHz, CDCl3) 2.42-2.50 (m, 2H), 2.78
(s, 2H), 3.91 (s, 3H), 5.26 (s, 2H), 6.98 (d, J ) 9.0 Hz, 2H), 7.4
Ack n ow led gm en t. Financial support from NSERC
is gratefully acknowledged. We thank Nadim Saade for
the mass spectral data.
Su p p or tin g In for m a tion Ava ila ble: Copies of 1H and 13C
NMR spectra of 5, 6, 7 (R ) nBu), 14, 19-21, 23-26, 28-31,
and the products of Table 1, entries 7, 10, and 11 (36 pages).
This material is contained in libraries on microfiche, im-
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J O960245N