Preparation of Vinylcyclopropanes by the Titanocene-Promoted Reactions of β,γ-Unsaturated Thioacetals and Their Analogues with Alkenes

Article abstract of DOI:10.1021/jo962265v

Preparation of vinylcyclopropanes 6 utilizing 2-(alk-1-enyl)-1,3-dithianes 1 or 1,3-bis(phenylthio)alk-1-enes 2 was studied. The treatment of β,β-unsaturated thioacetals 1 or their analogues 2 with Cp₂Ti(π-CH₂=CR₃R₄

Full text of DOI:10.1021/jo962265v

3
678
J . Org. Chem. 1997, 62, 3678-3682
P r ep a r a tion of Vin ylcyclop r op a n es by th e Tita n ocen e-P r om oted
Rea ction s of â,γ-Un sa tu r a ted Th ioa ceta ls a n d Th eir An a logu es
w ith Alk en es
Yasuo Horikawa, Tadahiro Nomura, Mikako Watanabe, Tooru Fujiwara, and
Takeshi Takeda*
Department of Applied Chemistry, Tokyo University of Agriculture and Technology,
Koganei, Tokyo 184, J apan
Received December 4, 1996
Preparation of vinylcyclopropanes 6 utilizing 2-(alk-1-enyl)-1,3-dithianes 1 or 1,3-bis(phenylthio)alk-
1
-enes 2 was studied. The treatment of â,γ-unsaturated thioacetals 1 or their analogues 2 with
Cp Ti(π-CH dCR ) 5 in the presence of PPh or P(OEt) gave vinylcyclopropanes 6 in good yields.
A part of the cyclopropane 6 originates from the alkene formed by the thermal degradation of
dialkyltitanocene 4, an intermediate formed during the reduction of Cp TiCl with alkyllithium to
. By using the titanocene reagent Cp Ti(P(OEt) 7 as a reducing agent, cyclopropanes 6 were
obtained by the reaction of unsaturated organosulfur compounds 1 or 2 with various alk-1-enes.
,2-Dibromoalkanes could be successfully employed as substitutes for volatile alkenes in this
reaction. The intermediate of this reaction is presumed to be a vinylcarbene complex of titanium
2
2
3
R
4
3
3
2
2
5
2
3 2
)
1
8
.
In tr od u ction
Organometallic reagents play an important role in
Sch em e 1
modern synthetic organic chemistry, and a variety of
approaches have been developed to prepare these re-
agents. In particular, we have been interested in the
desulfurizative metalation of organosulfur compounds
using stannyl- and germylmetal reagents which has
shown to be useful in the synthesis of organotin and
1
germanium compounds. Our group has recently shown
that the reductive desulfurization of allylic sulfides with
the low-valent titanium species “Cp
2
Ti”, prepared by
treatment of Cp TiCl with butyllithium, affords allyl-
titanium species. These species can be converted to the
2
2
by reaction of metal-carbene complexes or carbenes with
dienes,9 or reacting Wittig reagent with cyclopropyl
anti-homoallyl alcohols with high regio- and diastereo-
1
0
selectivity upon treatment with aldehydes.2
ketones or cyclopropanecarbaldehydes. However, all of
In a related study, we were interested in forming the
synthetically useful intermediates shown as 3a and 3b
in Scheme 1 via reduction of â,γ-unsaturated thioacetals
(5) Reviews: (a) Goldschmidt, Z.; Crammer, B. Chem. Soc. Rev.
1988, 17, 229. (b) Hudlicky, T.; Kutchan, T. M.; Naqvi, S. M. Org. React.
3
1
989, 33, 247. (c) Hudlicky, T.; Reed, J . W. In Comprehensive Organic
1
2
or 1,3-bis(phenylthio)alk-1-enes 2 with “Cp Ti”. This
Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford,
1991; Vol. 5, p 899. (d) Khusnutdinov, R. I.; Dzhemilev, U. M. J .
Organomet. Chem. 1994, 471, 1.
proposed reaction pathway was based on the work of
Taguchi et al., who reported that the butene complex of
zirconocene reacts with acetals of R,â-unsaturated alde-
(6) For the transformation to cyclopentenes, see: (a) McGaffin, G.;
de Meijere, A.; Walsh, R. Chem. Ber. 1991, 124, 939. (b) Davies, H. M.
L.; Hu, B. Tetrahedron Lett. 1992, 33, 453. (c) Dolbier, W. R., J r.;
McClinton, M. A. J . Fluorine Chem. 1995, 70, 249. (d) Asuncion, L.
A.; Baldwin, J . E. J . Org. Chem. 1995, 60, 5778. (e) Gajewski, J . J .;
Olson, L. P.; Willcott, M. R., III. J . Am. Chem. Soc. 1996, 118, 299.
(7) For the transformation to dienes, see: (a) Parziale, P. A.; Berson,
J . A. J . Am. Chem. Soc. 1991, 113, 4595. (b) Ogle, C. A.; Black, K. C.;
Sims, P. F. J . Org. Chem. 1992, 57, 3499. (c) Hanzawa, Y.; Harada,
S.; Nishio, R.; Taguchi, T. Tetrahedron Lett. 1994, 35, 9421. (d)
Dimmock, P. W.; Whitby, R. J . J . Chem. Soc., Chem. Commun. 1994,
hydes to afford either (R- or (γ-alkoxyallyl)zirconium
reagents.4 Contrary to our expectation, however, no
allyltitanium species 3 was obtained, and instead vinyl-
cyclopropanes 6 were selectively produced.
Vinylcyclopropanes 6 are valuable synthetic intermedi-
ates as homologues of 1,3-dienes and are easily trans-
formed into cyclopentenes or dienes by the thermal,
transition metal-catalyzed, or photochemical isomeri-
zation.5 In general, vinylcyclopropanes are synthesized
2
323.
(
8) For the divinylcyclopropane-cycloheptadiene rearrangement,
-8
see: (1) Hudlicky, T.; Fan, R.; Reed, J . W.; Gadamasetti, K. G. Org.
React. 1992, 41, 1. (b) Erbes, P.; Boland, W. Helv. Chim. Acta 1992,
7
5, 766.
X
Abstract published in Advance ACS Abstracts, May, 1; 1997.
(9) For example: (a) Harvey, D. F.; Lund, K. P. J . Am. Chem. Soc.
(
1) (a) Takeda, T.; Ando, K.; Mamada, A.; Fujiwara, T. Chem. Lett.
1991, 113, 8916. (b) de Meijere, A.; Schulz, T.-J .; Kostikov, R. R.;
Graupner, F.; Murr, T.; Bielfeldt, T. Synthesis 1991, 547. (c) Taber, D.
F.; Hoerrner, R. S. J . Org. Chem. 1992, 57, 441. (d) Shavrin, K. N.;
Okonnishnikova, G. P.; Nefedov, O. M. Izv. Akad. Nauk SSSR, Ser.
Khim. 1991, 2552; Chem. Abstr. 1992, 116, 83002q. (e) Weng, W.-W.;
Luh, T.-Y. J . Chem. Soc., Perkin Trans. 1 1993, 2687. (f) Al Dulayymi,
J . R.; Baird, M. S.; Rajaram, L.; Clegg, W. J . Chem. Res. (S) 1994,
344. (g) Nishiyama, H.; Itoh, Y.; Sugawara, Y.; Matsumoto, H.; Aoki,
K.; Itoh, K. Bull. Chem. Soc. J pn. 1995, 68, 1247. For synthesis by
the reaction of ruthenium-vinylcarbene complex with styrene, see:
Nishiyama, H.; Park, S.-B.; Itoh, K. Chem. Lett. 1995, 599.
1
985, 1149. (b) Takeda, T.; Oshima, H.; Inoue, M.; Togo, A.; Fujiwara,
T. Chem. Lett. 1987, 1345. (c) Takeda, T.; Ogawa, S.; Ohta, N.;
Fujiwara, T. Chem. Lett. 1987, 1967. (d) Yamaguchi, J .; Tamada, Y.;
Takeda, T. Bull. Chem. Soc. J pn. 1993, 66, 607.
(
2) Takeda, T.; Miura, I.; Horikawa, Y.; Fujiwara, T. Tetrahedron
Lett. 1995, 36, 1495.
3) Furuta, K.; Ikeda, Y.; Meguriya, N.; Ikeda, N.; Yamamoto, H.
Bull. Chem. Soc. J pn. 1984, 57, 2781.
4) Ito, H.; Taguchi, T.; Hanzawa, Y. Tetrahedron Lett. 1992, 33,
873.
(
(
7
S0022-3263(96)02265-7 CCC: $14.00 © 1997 American Chemical Society

J . Org. Chem., Vol. 62, No. 11, 1997 3679
Ta ble 1. P r ep a r a tion of Vin ylcyclop r op a n es 6 Usin g Cp 2Ti(π-CH2dCR3R4) 5a
Sch em e 2
these methods are either limited by the structure of the
substituent on the cyclopropane ring or else involve
multistep reaction routes. From our standpoint, use of
2
“Cp Ti” to form vinylcyclopropanes presented an interest-
ing mechanistic challenge because this reaction should
theoretically proceed via a metal-carbene intermediate.
6
Luh et al. have shown that W(CO) promotes self-coupling
of thioacetals,11 presumably via a metal-carbene, but our
reaction presents the first transformation of thioacetals
to vinylcyclopropanes that involves cross-coupling reac-
tion of a metal-carbene intermediate with an alkene.
In this paper, we report the preparation of vinylcyclo-
propanes by treatment of unsaturated thioacetals or their
6 was isolated by thin layer chromatography. It was
found that a portion of the products contained substitu-
ents which originated from the alkene formed during
thermal degradation of 4 (Scheme 2). The formation of
alkene by thermolysis of dialkyltitanocene has been well
documented by Whitesides et al.13 These results suggest
that the reactive intermediate is the alkene complex of
analogues with the titanocene-olefin complexes Cp
CH dCR
) 5,12 including improved procedures which
use the alkene-free titanocene Cp Ti(P(OEt) 7. This
2
Ti(π-
2
3 4
R
2
3 2
)
methodology is general for the synthesis of vinylcyclo-
propanes in good to high yields.
Resu lts a n d Discu ssion
titanium(II), Cp
were also obtained under similar conditions when
treating 1,3-bis(phenylthio)alk-1-ene 2 with 5 (Table 1).
E)-1,1-Dimethyl-2-(2-phenylethenyl)cyclopropane (6a )
was obtained in an exceptionally good yield by the
reaction of 2-(2-phenylethenyl)-1,3-dithiane (1a ) with
2
Ti(π-CH
2 3 4
dCR R ) 5. Vinylcyclopropanes
6
Dibutyltitanocenes 4 were prepared by treating THF
solution of Cp
butyllithium at -78 °C for 15 min. After addition of
-(alk-1-enyl)-1,3-dithiane 1, the reaction mixture was
warmed to room temperature, and the vinylcyclopropane
2 2
TiCl with 2 equiv of either n- or tert-
(
2
Cp
2
2 3 2
Ti(π-CH dC(CH ) ) 5. However, the yields of 6 were
generally lower, attributable, in part, to the instability
of 5 under the reaction conditions. We then examined
various ligands containing phosphorus or nitrogen to
stabilize the titanium species 5. After several attempts,
it was found that cyclopropanes 6 were prepared in better
yields when the reactions were performed in the presence
(
10) For example: (a) Feldman, K. S.; Simpson, R. E. J . Am. Chem.
Soc. 1989, 111, 4878. (b) Parziale, P. A.; Berson, J . A. J . Am. Chem.
Soc. 1991, 113, 4595. (c) Baldwin, J . E.; Bonacorsi, S., J r. J . Org. Chem.
1
994, 59, 7401. (d) Yamazaki, S.; Tanaka, M.; Yamaguchi, A.; Yamabe,
S. J . Am. Chem. Soc. 1994, 116, 2356.
11) (a) Luh, T.-Y.; Wong, C. S. J . Org. Chem. 1985, 50, 5413. (b)
Yeung, L. L.; Yip, Y. C.; Luh, T.-Y. J . Chem. Soc., Chem. Commun.
987, 981. (c) Wong, C. S.; Leung, W. S.; Yeung, L. L.; Luh, T.-Y. J .
(
1
3 3
of PPh or P(OEt) (Table 2).
Organomet. Chem. 1986, 307, C49. (d) Ng, D. K. P.; Luh, T.-Y.
Tetrahedron Lett. 1988, 29, 5131. (e) Wang, X.-J .; Luh, T.-Y. J . Org.
Chem. 1989, 54, 263. (f) Yeung, L. L.; Yip, Y. C.; Luh, T.-Y. J . Org.
Chem. 1990, 55, 1874. (g) Tip, Y. C.; Wang, X.-J .; Ng, D. K. P.; Mak,
T. C. W.; Chiang, P.; Luh, T.-Y. J . Org. Chem. 1990, 55, 1881. (h) Kuo,
C.-H.; Luh, T.-Y. J . Chem. Soc., Chem. Commun. 1990, 1187.
Although the vinylcyclopropanes 6 shown in Table 1
and 2 were obtained in good isolated yields, the synthetic
application of this method was largely restricted by the
need to prepare a suitable alkyllithium reagent. In
(
12) Preliminary communication: Horikawa, Y.; Nomura, T.; Wa-
tanabe, M.; Miura, I.; Fujiwara, T.; Takeda, T. Tetrahedron Lett. 1995,
6, 8835.
(13) McDermott, J . X.; Wilson, M. E.; Whitesides, G. M. J . Am.
Chem. Soc. 1976, 98, 6529.
3

3
680 J . Org. Chem., Vol. 62, No. 11, 1997
Ta ble 2. P r ep a r a tion of Vin ylcyclop r op a n es 6 Usin g Cp 2Ti(π-CH2dCR3R4) 5/P R3a
Ta ble 3. P r ep a r a tion of Vin ylcyclop r op a n es 6 by th e
Rea ction of 1a w ith Alk en es Usin g Cp 2Ti(π-CH2dCR3R4)
Sch em e 3
a
5
/P (OEt)3
1
3
-phenyl-2-(2-phenylethenyl)cyclopropane (6g) (Scheme
), in which the trans isomer predominated6 (entry 3,
d
Table 4). Similarly, 1-hexyl-2-(2-phenylethenyl)cyclo-
propane (6h ) was isolated in 42% yield when oct-1-ene
was employed as a starting material (entry 4) and 72%
yield when 2 equiv of 7 was used (entry 5). In general,
the use of 2 equiv of 7 and 4-10 equiv of the alkene
produced the highest yields when alk-1-enes other than
styrene were employed. Similar reactions of 1,3-bis(phen-
ylthio)alk-1-enes 2 with various alkenes using Cp
P(OEt) 7 as a reducing agent also gave vinylcyclopro-
panes 6 in good to high yields.
2
Ti-
(
3 2
)
Reactions using volatile alkenes such as ethylene are
usually troublesome because they require high pressure
equipment and large excesses of alkene in certain cases.
From our point of view, the use of 1,2-dibromoalkanes
instead of alk-1-enes could alleviate this problem since
addition, complications arose when using an alkene as a
starting material in the above preparation because of the
formation of another alkene through decomposition of 4.
As a consequence, a mixture of products resulted (Table
1
,2-dibromoalkanes are readily reduced with magnesium
turnings to form alkenes prior to the reduction of
Cp TiCl in the same reaction vessel. Results showed
3
). To counter this problem, an alternative source of
titanocene(II), Cp Ti(P(OEt) 7, was employed.
The alkene-free titanocene Cp Ti(P(OEt) 7 was easily
prepared by the reduction of Cp TiCl with magnesium
turnings in the presence of P(OEt) and powdered mo-
lecular sieves 4A14 and has proven to be a successful
2
2
2
3 2
)
that when using 1,2-dibromoalkanes as starting materi-
als the corresponding vinylcyclopropanes 6 were obtained
in good yields (entries 2, 10, and 13).
2
3 2
)
2
2
3
The results summarized in Table 4 indicate that the
yield of 6 depends on the steric bulk of groups near the
double bond of the alkene. The reaction using the
hindered, 2-substituted alk-1-ene, 2-methylpent-1-ene,
gave the corresponding vinylcyclopropane 6i only in a
moderate yield (entry 6). A similar trend was observed
1
5
reagent in carbonyl olefination using thioacetals. As
was expected, the straightforward treatment of the
unsaturated thioacetal 1a with a mixture of 1 equiv of 7
and styrene (2 equiv) at room temperature produced (E)-
(
14) The NMR spectra of 7 in THF-d
8
exhibited a cyclopentadienyl
when using Cp
2
2 3 4
Ti(π-CH dCR R ) 5 in the presence of
1
13
resonance at δ 4.61 ( H NMR) and at δ 91.9 ( C NMR). Although the
characterization of 7 is incomplete, these chemical shifts are in good
agreement with the reported values of Cp
PMe
various alkenes (see Table 3). The fact that 1,1-dimethyl-
2-(4-phenylbut-1-enyl)cyclopropane (6e) was obtained in
a better yield by the reaction of 2b (entry 11, Table 4)
than by that of 1c (entry 8, Table 4) suggests that 1,3-
bis(phenylthio)alk-1-enes 2 are more reactive toward
a
2
Ti(P(OMe)
3
)
2
and Cp
2
Ti-
b
(
1
3
)
2
: (a) Chang, M.; Timms, P. L.; King, R. B. J . Organomet. Chem.
980, 199, C3. (b) Kool, L. B.; Raush, M. D.; Alt, H. G.; Herberhold,
M.; Thewalt, U.; Wolf, B. Angew. Chem., Int. Ed. Engl. 1985, 24, 394.
15) Horikawa, Y.; Watanabe, M.; Fujiwara, T.; Takeda, T. J . Am.
Chem. Soc. 1997, 119, 1127.
(
2 3 2
Cp Ti(P(OEt) ) 7 than 2-(alk-1-enyl)-1,3-dithianes 1.

J . Org. Chem., Vol. 62, No. 11, 1997 3681
Ta ble 4. P r ep a r a tion of Vin ylcyclop r op a n es 6 Usin g Cp 2Ti(P (OEt)3)2 7
Sch em e 4
Sch em e 5
This is possibly due to the phenylthio group being a better
leaving group than the alkylthio group.
ene-3,3-d
2
and 3,3-diphenylprop-1-ene-1,3-d
2
.15 It follows
A possible reaction path for our work is illustrated in
Schemes 4 and 5. We recently observed that the reaction
of the unsaturated thioacetal, 2-(2,2-diphenylethenyl)-
that the most likely intermediate formed by the desulfu-
rization of an unsaturated thioacetal 1 or its analogue 2
1
6
should be the vinylcarbene complex of titanium 8, which
then reacts with an alkene to give 6 via a titanacyclo-
butane intermediate 9 (Scheme 4). The favored trans
1
,3-dithiane with excess 7 followed by treatment with
O gave the dideuterated alkenes, 1,1-diphenylprop-1-
D
2

3
682 J . Org. Chem., Vol. 62, No. 11, 1997
stereochemistry of the cyclopropane moiety observed in
the reaction using styrene (entry 3, Table 4) seems to
arise from the favorable transition state geometry de-
picted in Scheme 5, in which 8 and styrene approach each
other so as to minimize steric repulsion.
1.50 (m, 2.6 H), 1.57-1.67 (m, 0.4 H), 5.77 (dd, J ) 15.6, 8.8
Hz, 0.6 H), 5.97 (dd, J ) 15.6, 8.8 Hz, 0.4 H), 6.40 (d, J ) 15.6
Hz, 0.6 H), 6.48 (d, J ) 15.6 Hz, 0.4 H), 7.10-7.18 (m, 1 H),
7
2
1
.20-7.35 (m, 4 H); 13C NMR δ 13.42, 14.06, 14.28, 19.59,
1.40, 22.06, 22.71, 23.36, 26.91, 125.48, 125.57, 126.37,
26.45, 126.73, 128.41, 129.39, 130.93, 134.68, 137.85, 138.00;
In conclusion, we have shown that the cyclopropana-
tion of alkenes using thioacetals of R,â-unsaturated
aldehydes 1 and 1,3-bis(phenylthio)alk-1-enes 2 is a
versatile method for the preparation of vinylcyclopro-
panes 6. The intermediate of this reaction is presumed
to be a vinylcarbene complex of titanium 8. Related
studies on the reaction of thioacetals with carbon-carbon
multiple bonds are currently underway.
IR (neat) 3062, 2960, 2873, 1649, 1492, 1461, 1448, 956, 752,
-
1
742, 692 cm ; HRMS calcd for C H 172.1251, found
1
3
16
172.1250. Anal. Calcd for C13
C, 90.63; H, 9.45.
H16: C, 90.64; H, 9.36. Found:
Syn th esis of (E)-1-Hexyl-2-(2-p h en yleth en yl)cyclop r o-
p a n e (6h ). Typ ica l P r oced u r e C. To a flask charged with
finely powdered molecular sieves 4A (50 mg), magnesium
turnings (97 mg, 4 mmol), and Cp
added THF (5 mL), P(OEt) (0.34 mL, 2 mmol), and oct-1-ene
224 mg, 2 mmol) successively with stirring at room temper-
2 2
TiCl (249 mg, 1 mmol) were
3
(
Exp er im en ta l Section
ature. After 2 h, 1a (111 mg, 0.5 mmol) in THF (2 mL) was
added to the reaction mixture which was further stirred for 4
Gen er a l. 1H (400 MHz) and 13C (100 MHz) NMR spectra
were recorded with CDCl as a solvent. All reactions were
3
h. The usual workup gave 6h (82 mg, 72%): 1H NMR δ 0.33
(
(
(
q, J ) 4.8 Hz, 0.4 H), 0.59 (dt, J ) 12.8, 4.8 Hz, 0.6 H), 0.66
dt, J ) 12.8, 4.8 Hz, 0.6 H), 0.80-1.09 (m, 3.4 H), 1.18-1.49
m, 10.6 H), 1.61 (dq, J ) 8.5, 5.4 Hz, 0.4 H), 5.76 (dd, J )
performed under an argon atmosphere in dried glassware. For
thin layer chromatography, Wakogel B-5F was used as an
adsorbent. THF was distilled from sodium and benzophenone.
1
5.6, 8.8 Hz, 0.6 H), 5.96 (dd, J ) 15.6, 8.8 Hz, 0.4 H), 6.40 (d,
1
7
2
-(Alk-1-enyl)-1,3-dithianes 1 and 1,3-bis(phenylthio)alk-1-
J ) 15.6 Hz, 0.6 H), 6.48 (d, J ) 15.6 Hz, 0.4 H), 7.10-7.19
1
8
enes 2 were prepared by the methods described in the
literature.
Syn th esis of (E)-1,1-Dim eth yl-2-(2-p h en yleth en yl)cy-
clop r op a n e (6a ). Typ ica l P r oced u r e A. To a THF (3 mL)
13
(m, 1 H), 7.19-7.38 (m, 4 H); C NMR δ 13.62, 14.07, 14.10,
1
2
1
4.49, 19.58, 19.62, 21.66, 22.36, 22.67, 29.12, 29.17, 29.33,
9.42, 29.73, 31.84, 31.89, 33.88, 125.49, 125.59, 126.39,
26.45, 126.74, 128.43, 129.31, 131.15, 134.73, 137.89, 138.03;
suspension of Cp
lithium (2 mmol) at -78 °C. After 15 min, 2-(2-phenylethenyl)-
,3-dithiane (1a ) (111 mg, 0.5 mmol) in THF (2 mL) was added
2 2
TiCl (249 mg, 1 mmol) was added butyl-
IR (neat) 2927, 2856, 1653, 1465, 1448, 1072, 1028, 957, 746,
-1
6
92 cm . Anal. Calcd for C17
H24: C, 89.41; H, 10.59. Found:
1
C, 89.76; H, 10.63.
to the reaction mixture which was further stirred for 15 min
at the same temperature, and then the cooling bath was
removed. After being stirred for an additional 3 h at room
temperature, the mixture was diluted with hexane (30 mL),
and the insoluble materials were filtered off through Celite.
The filtrate was concentrated under reduced pressure. The
crude product was purified by PTLC (hexane) to give 6a (62
Syn th esis of (3-P h en ylp r op -1-en yl)cyclop r op a n e (6j).
Typ ica l P r oced u r e D. To a flask charged with finely
powdered molecular sieves 4A (50 mg) and magnesium turn-
ings (146 mg, 6 mmol) were added THF (5 mL) and 1,2-
dibromoethane (376 mg, 2 mmol) successively with stirring
at 0 °C. After 4 h, Cp
0.34 mL, 2 mmol) were added to the reaction mixture, and
stirring was continued for 2 h at room temperature. A THF
2 2 3
TiCl (249 mg, 1 mmol) and P(OEt)
(
1
mg, 72%): H NMR δ 0.46-0.52 (m, 1 H), 0.74-0.80 (m, 1 H),
1
1
.12 (s, 3 H), 1.13 (s, 3 H), 1.37-1.46 (m, 1 H), 5.98 (ddd, J )
5.6, 9.2, 2.0 Hz, 1 H), 6.46 (d, J ) 15.6 Hz, 1 H), 7.12-7.19
(2 mL) solution of 4-phenyl-1,3-bis(phenylthio)but-1-ene 2a
(174 mg, 0.5 mmol) was added to the reaction mixture, and it
1
3
(
m, 1 H), 7.22-7.35 (m, 4 H); C NMR δ 19.66, 20.78, 22.30,
was further stirred for 4 h. The usual workup gave 6j (64 mg,
2
7.07, 28.52, 125.59, 126.46, 128.45, 129.17, 131.66, 137.98;
IR (neat) 3060, 2992, 2944, 2867, 1644, 1494, 1448, 1120, 1079,
027, 1004, 960, 939, 748, 694 cm-1. Anal. Calcd for C13
C, 90.64; H, 9.36. Found: C, 90.89; H, 9.36.
1%): 1H NMR δ 0.32-0.47 (m, 2 H), 0.64-0.76 (m, 1.78 H),
8
0
0
.78-0.85 (m, 0.22 H), 1.36-1.50 (m, 1.78 H), 1.68-1.79 (m,
.22 H), 3.43 (d, J ) 7.2 Hz, 0.89 H), 3.59 (d, J ) 7.2 Hz, 0.11
1
16
H :
H), 4.93 (t, J ) 10.8 Hz, 0.11 H), 5.09 (dd, J ) 14.8, 10.8 Hz,
Syn th esis of (E)-1-Eth yl-2-(2-p h en yleth en yl)cyclop r o-
p a n e (6b). Typ ica l P r oced u r e B. To a THF (3 mL)
0
6
9
1
.89 H), 5.53 (dt, J ) 10.8, 7.6 Hz, 0.11 H), 5.69 (dt, J ) 14.8,
13
.8 Hz, 0.89 H), 7.14-7.46 (m, 5 H); C NMR δ 6.44, 6.95,
suspension of Cp
lithium (2 mmol) at -78 °C. After 15 min, a THF (2 mL)
solution of 1a (111 mg, 0.5 mmol) and PPh (262 mg, 1 mmol)
2 2
TiCl (249 mg, 1 mmol) was added butyl-
.63, 13.50, 33.88, 38.86, 125.82, 125.85, 126.35, 126.57,
28.32, 128.38, 128.45, 134.92, 135.32, 141.01, 141.30; IR
3
(
1
C
9
neat) 3083, 3064, 3027, 3006, 2958, 2904, 2838, 1604, 1494,
was successively added to the reaction mixture which was
further stirred for 15 min at the same temperature, and then
the cooling bath was removed. After being stirred for 24 h at
-1
454, 1047, 1030, 1022, 960, 740, 698 cm ; HRMS calcd for
14 158.1095, found 158.1089. Anal. Calcd for C12
1.08; H, 8.92. Found: C, 90.97; H, 9.04.
12
H
H14: C,
room temperature, the workup used in procedure A afforded
1
6
(
b (66 mg, 77%): H NMR δ 0.29-0.35 (m, 0.4 H), 0.56-0.68
Ack n ow led gm en t. The authors are indebted to Ms.
M. Fukuta (Technical Center, Bridgestone Corporation)
for mass spectral analysis.
m, 1.2 H), 0.79-0.89 (m, 0.6 H), 0.91-1.05 (m, 3.8 H), 1.22-
a
(
16) A limited number of vinylcarbene complexes of titanium,
a
b
c
zirconium, ruthenium, and tungsten have been prepared using 3,3-
disubstituted cyclopropenes as starting materials: (a) Binger, P.;
M u¨ ller, P.; Benn, R.; Mynott, R. Angew. Chem., Int. Ed. Engl. 1989,
Su ppor tin g In for m ation Available: Characterization data
for compounds 6c, 6d , 6e, 6f, 6g, 6i, 6k , and 6l (3 pages). This
material is contained in libraries on microfiche, immediately
follows this article in the microfilm version of the journal, and
can be ordered from the ACS; see any current masthead page
for ordering information.
2
8, 610. (b) Nguyen, S. T.; J ohnson, L. K.; Grubbs, R. H. J . Am. Chem.
Soc. 1992, 114, 3974. (c) J ohnson, L. K.; Grubbs, R. H.; Ziller, J . W. J .
Am. Chem. Soc. 1993, 115, 8130.
(
17) Ni, Z.-J .; Luh, T.-Y. Org. Synth. 1991, 70, 240.
(18) Corey, E. J .; Erickson, B. W.; Noyori, R. J . Am. Chem. Soc. 1971,
9
3, 1724.
J O962265V