Nickel-Catalyzed Coupling Reaction of 1,3-Disubstituted Secondary Allylic Carbonates and Lithium Aryl- and Alkenylborates

Article abstract of DOI:10.1021/jo960458c

Tis account describes coupling reaction of 1,3-disubstituted secondary allylic carbonates with lithium aryl- and alkenylborates in the presence of a nickel catalyst.Borates examined are 4, 5, and 6, and reactivity and selectivity were investigated using t

Full text of DOI:10.1021/jo960458c

J . Org. Chem. 1996, 61, 5391-5399
5391
Nick el-Ca ta lyzed Cou p lin g Rea ction of 1,3-Disu bstitu ted
Secon d a r y Allylic Ca r bon a tes a n d Lith iu m Ar yl- a n d
Alk en ylbor a tes
Yuichi Kobayashi,* Ryo Mizojiri, and Eitatsu Ikeda
Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho,
Midori-ku, Yokohama 226, J apan
Received March 5, 1996X
This account describes coupling reaction of 1,3-disubstituted secondary allylic carbonates with
lithium aryl- and alkenylborates in the presence of a nickel catalyst. Borates examined are 4, 5,
and 6, and reactivity and selectivity were investigated using the allylic carbonates 1a and 1b.
Coupling of 1a ,b with borates 4 was effected with the nickel catalyst, NiCl2(PPh3)2 or NiCl2(dppf),
in THF at 45-65 °C to provide products 3 in good yields with almost 100% regio- and
stereoselectivities. Trivalent organoboranes prepared from acetylenes by hydroboration with
catecholborane also underwent coupling reaction with 1a ,b after transformation to borates 5 with
MeLi. Though coupling using 4 and 5 required elevated temperature (45-65 °C), cyclic borates 6
prepared in situ from boronates 8 and MeLi were found to couple with 1a ,b at room temperature
or below. Regio- and stereoselectivities were almost 100% as were observed in the cases of 4 and
5. In these reactions, palladium complexes such as Pd(PPh3)4, Pd2(dba)3‚CHCl3 + 2 PPh3 showed
no catalytic activity. Stereochemical aspect of the present reaction was studied using cyclohexenyl
carbonate 24 with 2-furylborate 4e and phenylborate 6a , and was found to proceed with overall
anti fashion. With additional experiments, the mechanism of the present reaction was discussed
in terms of transient π-allylnickel intermediates.
In tr od u ction
important coupling process in organic synthesis. How-
ever, reactions with such sterically hindered substrates
have been examined to some extent with highly reactive
Grignard reagents. Thus, we initiated a study to find a
Transition metal-catalyzed coupling reactions of allylic
substrates with aryl- and alkenyl-metallic reagents are
an important carbon-carbon bond-forming reactions in
organic synthesis.1 Numerous organometallic reagents
based on aluminum,2 boron,3 magnesium,4 tin,3i,5 zinc,2c,e,6
zirconium,2a,d,f,7 and mercury8 have been reported to enter
into the coupling reaction with allylic alcohol derivatives
and halides mostly in the presence of palladium and/or
nickel catalysts.9 In general, allylic halides show higher
reactivity than alcohol derivatives, and the reaction is
influenced by steric hindrance from π-allylmetal inter-
mediates. We propose that the reaction of 1,3-disubsti-
tuted secondary allylic alcohol derivatives is a most
(4) (a) Chuit, C.; Felkin, H.; Frajerman, C.; Roussi, G.; Swierczewski,
G. J . Chem. Soc., Chem. Commun. 1968, 1604. (b) Felkin, H.;
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1977, 127, 371. (d) Okamura, H.; Takei, H. Tetrahedron Lett. 1979,
3425. (e) Wenkert, E. Chimia 1981, 35, 257. (f) Felkin, H.; J oly-
Goudket, M.; Davies, S. G. Tetrahedron Lett. 1981, 22, 1157. (g)
Wenkert, E.; Fernandes, J . B.; Michelotti, E. L.; Swindell, C. S.
Synthesis 1981, 701. (h) Hayashi, T.; Konishi, M.; Yokota, K.; Kumada,
M. J . Organomet. Chem. 1985, 285, 359. (i) Sugimura, H.; Takei, H.
Chem. Lett. 1985, 351. (j) Hiyama, T.; Wakasa, N. Tetrahedron Lett.
1985, 26, 3259. (k) Consiglio, G.; Piccolo, O.; Roncetti, L. Tetrahedron
1986, 42, 2043. (l) Fotiadu, F.; Cros, P.; Faure, B.; Buono, G.
Tetrahedron Lett. 1990, 31, 77. (m) Yanagisawa, A.; Nomura, N.;
Yamamoto, H. Tetrahedron 1994, 50, 6017. (n) Didiuk, M. T.; Morken,
J . P.; Hoveyda, A. H. J . Am. Chem. Soc. 1995, 117, 7273. (o) Moineau,
C.; Bolitt, V.; Sinou, D. J . Chem. Soc., Chem. Commun. 1995, 1103.
Cf. copper(I)-catalyzed reactions: (p) Bourgain-Commercon, M.; Nor-
mant, J .-F.; Villieras, J . J . Chem. Res. (S) 1977, 183; J . Chem. Res.
(M) 1977, 2101. (q) Cahiez, C.; Alexakis, A.; Normant, J . F. Synthesis
1978, 528. (r) Sato, T.; Takeuchi, M.; Itoh, T.; Kawashima, M.;
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3583. (t) Tseng, C. C.; Paisley, S. D.; Goering, H. L. J . Org. Chem.
1986, 51, 2884. (u) Underiner, T. L.; Paisley, S. D.; Schmitter, J .;
Lesheski, L.; Goering, H. L. J . Org. Chem. 1989, 54, 2369. (v) Ba¨ckvall,
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Chem. 1994, 59, 4126.
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106, 4833. (d) Hibino, J .; Matsubara, S.; Morizawa, Y.; Oshima, K.;
Nozaki, H. Tetrahedron Lett. 1984, 25, 2151. (e) Kosugi, M.; Ohashi,
K.; Akuzawa, K.; Kawazoe, T.; Sano, H.; Migita, T. Chem. Lett. 1987,
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M.; Stille, J . K. Tetrahedron 1989, 45, 979. (h) Tolstikov, G. A.;
Miftakhov, M. S.; Danilova, N. A.; Vel’der, Y. L.; Spirikhin, L. V.
Synthesis 1989, 625. (i) Valle, L. D.; Stille, J . K.; Hegedus, L. S. J .
Org. Chem. 1990, 55, 3019. (j) Farina, V.; Baker, S. R.; Benigni, D. A.;
Hauck, S. I.; Sapino, C., J r. J . Org. Chem. 1990, 55, 5833.
X Abstract published in Advance ACS Abstracts, August 1, 1996.
(1) Reviews: (a) Tamao, K. In Comprehensive Organic Synthesis;
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1991; Vol. 3, p 435. (b) Consiglio, G.; Waymouth, R. M. Chem. Rev.
1989, 89, 257. (c) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457.
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Chem. 1991, 56, 2918. (e) Hutzinger, M. W.; Oehlschlager, A. C. J .
Org. Chem. 1995, 60, 4595. (f) Flemming, S.; Kabbara, J .; Nickisch,
K.; Westermann, J .; Mohr, J . Synlett 1995, 183.
(3) Reactions with allylic esters: (a) Legros, J .-Y.; Fiaud, J .-C.
Tetrahedron Lett. 1990, 31, 7453. (b) Miyaura, N.; Yamada, K.;
Suginome, H.; Suzuki, A. J . Am. Chem. Soc. 1985, 107, 972. With allylic
halides: (c) Miyaura, N.; Yano, T.; Suzuki, A. Tetrahedron Lett. 1980,
21, 2865. (d) Yatagai, H. Bull. Chem. Soc. J pn. 1980, 53, 1670. (e)
Hoshi, M.; Masuda, Y.; Arase, A. Bull. Chem. Soc. J pn. 1983, 56, 2855.
(f) Hoshi, M.; Masuda, Y.; Nunokawa, Y.; Arase, A. Chem. Lett. 1984,
1029. (g) Miyaura, N.; Suginome, H.; Suzuki, A. Tetrahedron Lett. 1984,
25, 761. (h) Hoshi, M.; Masuda, Y.; Arase, A. Bull. Chem. Soc. J pn.
1986, 59, 659. (i) Kurosawa, H.; Ogoshi, S.; Kawasaki, Y.; Murai, S.;
Miyoshi, M.; Ikeda, I. J . Am. Chem. Soc. 1990, 112, 2813. With other
substrates: (j) Miyaura, N.; Tanabe, Y.; Suginome, H.; Suzuki, A. J .
Organomet. Chem. 1982, 233, C13. (k) Sasaya, F.; Miyaura, N.; Suzuki,
A. Bull. Korean Chem. Soc. 1987, 8, 329. (l) Trost, B. M.; Spagnol, M.
D. J . Chem. Soc., Perkin Trans. 1 1995, 2083. Cf. copper-induced
couplings: (m) Brown, H. C.; Campbell, J . B., J r. J . Org. Chem. 1980,
45, 550. (n) Yatagai, H. J . Org. Chem. 1980, 45, 1640. See also ref
13c.
S0022-3263(96)00458-6 CCC: $12.00 © 1996 American Chemical Society

5392 J . Org. Chem., Vol. 61, No. 16, 1996
Kobayashi et al.
Ch a r t 1. Bor a tes 4-6 u sed a s 2 in th e Cou p lin g
Rea ction w ith 1 (eq 1)
7 via hydroboration with catecholborane followed by
reaction with MeLi (eq 3).
new reagent/catalyst system, so that secondary allylic
substrates could react under mild conditions and still
tolerate reactive functional groups.
Reaction conditions were explored with the 1,3-disub-
stituted allylic carbonate 1a . In considering synthetic
application, the ester 1b was also selected as the sub-
strate: installation of sp2 species at the γ position of R,â-
unsaturated esters.12 Although our attempts to apply the
We selected lithium aryl- and alkenyl-borates 2 (eq 1)
for the following reasons: (1) NaBPh4,3a one of the
organoborates, as well as trivalent organoboranes3b couple
mostly with 1- or 3-monosubstituted primary allylic
acetates in the presence of palladium catalysts; (2) in
general, borates are almost neutral species; (3) several
methods are known for the preparation of organoborates
and/or their precursors.10,11 In practice the borates 4 and
5 shown in Chart 1 were chosen as reagents for 2 and
prepared in situ from the corresponding organolithiums
and B(OMe)3 (eq 2) or from the corresponding acetylenes
literature reaction conditions involving palladium cata-
lysts to the coupling of 1a with 4,5 were in vain, nickel
complexes were found to catalyze the coupling to provide
3 regioselectively (eq 1). Since higher temperatures (45-
65 °C) are needed, we have continued this investigation
and discovered that borates 6 derived from cyclic bor-
onates 8 and MeLi (eq 4) are more reactive reagents, and
the reaction proceeds at room temperature or below. In
this paper we describe a full account of these new
reagent/catalyst systems.13
(6) (a) Dunkerton, L. V.; Serino, A. J . J . Org. Chem. 1982, 47, 2812.
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383. (d) Hayashi, T.; Yamamoto, A.; Hagihara, T. J . Org. Chem. 1986,
51, 723. (e) Fiaud, J .-C.; Legros, J .-Y. J . Org. Chem. 1987, 52, 1907.
(f) Agrios, K. A.; Srebnik, M. J . Org. Chem. 1994, 59, 5468.
(7) (a) Hayashi, Y.; Riediker, M.; Temple, J . S.; Schwartz, J .
Tetrahedron Lett. 1981, 22, 2629. (b) Temple, J . S.; Riediker, M.;
Schwartz, J . J . Am. Chem. Soc. 1982, 104, 1310. (c) Wipf, P.; Xu, W.
J . Org. Chem. 1993, 58, 825. (d) Footnote 19 of Temple, J . S.; Schwartz,
J . J . Am. Chem. Soc. 1980, 102, 7381.
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C.; Bernhardt, J . C.; Driggs, R. J . J . Organomet. Chem. 1978, 156, 45.
(c) Larock, R. C.; Ilkka, S. J . Tetrahedron Lett. 1986, 27, 2211.
(9) Other organometallics: Larock, R. C.; Ding, S. J . Org. Chem.
1993, 58, 804.
(10) (a) Bean, F. R.; J ohnson, J . R. J . Am. Chem. Soc. 1932, 54, 4415.
(b) Sugihara, J . M.; Bowman, C. M. J . Am. Chem. Soc. 1958, 80, 2443.
(c) Evans, D. A.; Crawford, T. C.; Thomas, R. C.; Walker, J . A. J . Org.
Chem. 1976, 41, 3947. (d) Brown, H. C.; Bhat, N. G.; Somayaji, V.
Organometallics 1983, 2, 1311. (e) Brown, H. C.; Cole, T. E. Organo-
metallics 1983, 2, 1316. (f) Brown, H. C.; Imai, T. Organometallics
1984, 3, 1392. (g) Thompson, W. J .; Gaudino, J . J . Org. Chem. 1984,
49, 5237. (h) Miller, R. B.; Dugar, S. Organometallics 1984, 3, 1261.
(i) Sharp, M. J .; Cheng, W.; Snieckus, V. Tetrahedron Lett. 1987, 28,
5093. (j) Hoshino, Y.; Miyaura, N.; Suzuki, A. Bull. Chem. Soc. J pn.
1988, 61, 3008. (k) Helgeson, R. C.; Czech, B. P.; Chapoteau, E.;
Gebauer, C. R.; Kumar, A.; Cram, D. J . J . Am. Chem. Soc. 1989, 111,
6339. (l) Roush, W. R.; Ando, K.; Powers, D. B.; Palkowitz, A. D.;
Halterman, R. L. J . Am. Chem. Soc. 1990, 112, 6339. (m) Watanabe,
T.; Miyaura, N.; Suzuki, A. Synlett 1992, 207. (n) Takai, K.; Shinomiya,
N.; Kaihara, H.; Yoshida, N.; Miriwake, T.; Utimoto, K. Synlett 1995,
963.
(11) (a) Brown, H. C.; Gupta, S. K. J . Am. Chem. Soc. 1975, 97, 5249.
(b) Brown, H. C.; Chandrasekharan, J . J . Org. Chem. 1983, 48, 5080.
(c) Ma¨nnig, D.; No¨th, H. Angew. Chem., Int. Ed. Engl. 1985, 24, 878.
(d) Hoffmann, R. W.; Dresely, S. Synthesis 1988, 103. (e) Martinez-
Fresneda, P.; Vaultier, M. Tetrahedron Lett. 1989, 30, 2929. (f) Suseela,
Y.; Prasad, A. S. B.; Periasamy, M. J . Chem. Soc., Chem. Commun.
1990, 446. (g) Tucker, C. E.; Davidson, J .; Knochel, P. J . Org. Chem.
1992, 57, 3482.
Resu lts a n d Discu ssion
Cou p lin g Rea ction of 1 w ith Meth oxybor a tes 4.
The borates 4a -f (R3
) Ph, MeOC6H4, 2-furyl,
C(Me)dCH2) were prepared by mixing the corresponding
organolithium and B(OMe)3 at 0 °C for 15 min in THF
(eq 2) and used immediately for the coupling reaction
without isolation. Preliminary examination was carried
out by using the allylic carbonate 1a and 2-3 equiv of
phenylborate (4a , R3 ) Ph) or 2-furylborate (4e, R3
)
2-furyl) in the presence of 5-10 mol % of a palladium or
a nickel complex in THF. The products were analyzed
1
by 300 MHz H NMR spectroscopy, and the results are
summarized in Table 1. When reaction was attempted
with 4a at 60 °C in the presence of 10 mol % Pd(PPh3)2
14
(prepared in situ from Pd2(dba)3‚CHCl3 and 2 equiv of
PPh3) according to Fiaud,3a methyl ether 9 was obtained
as the major product (66% yield), and the yield of the
desired product 3a (R1 ) R3 ) Ph, R2 ) n-C5H11) was
<10% (entry 1). Formation of 9 was also catalyzed by
(12) (a) Stork, G.; Danheiser, R. L. J . Org. Chem. 1973, 33, 1775.
(b) Green, J . R.; Carroll, M. K. Tetrahedron Lett. 1991, 32, 1141. (c)
Ono, M.; Yamamoto, Y.; Todoriki, R.; Akita, H. Heterocycles 1994, 37,
181. (d) Nagumo, S.; Irie, S.; Akita, H. J . Chem. Soc., Chem. Commun.
1995, 2001.
(13) Preliminary communications using the borates 4 and 5: (a)
Kobayashi, Y.; Ikeda, E. J . Chem. Soc., Chem. Commun. 1994, 1789.
(b) Kobayashi, Y.; Mizojiri, R.; Ikeda, E. Synlett 1995, 571. Related
study: (c) Mizojiri, R.; Kobayashi, Y. J . Chem. Soc., Perkin Trans. 1
1995, 2073.
(14) Ukai, T.; Kawazura, H.; Ishii, Y.; Bonnet, J . J .; Ibers, J . A. J .
Organomet. Chem. 1974, 65, 253.

Ni-Catalyzed Coupling of Allylic Carbonates and Lithium Borates
J . Org. Chem., Vol. 61, No. 16, 1996 5393
Ta ble 1. P a lla d iu m - a n d Nick el-Ca ta lyzed Cou p lin g
Rea ction of 1 a n d 4a
borate
R3
yield, %
3b
carbonate
entry
catalyst
1
4
9
c
1
2
3
4
5
6
7
8
9
Pd(PPh3)2
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a
1b
4a Ph
4a Ph
4a Ph
4a Ph
4b o-MeOC6H4 3b, 86
4c m-MeOC6H4 3c, 81
4d p-MeOC6H4 3d , 89
4e 2-furyl
4e 2-furyl
4f C(Me)dCH2 3f, 46
4e 2-furyl 3g, 67
3a , <10 66
Pd(dppf)c
3a ,
0
54
0
Pd(dppf)15 (dppf ) 1,1′-bis(diphenylphosphino)ferrocene)
NiCl2(PPh3)2
NiCl2(dppf)
NiCl2(dppf)
NiCl2(dppf)
NiCl2(dppf)
NiCl2(PPh3)2
NiCl2(dppf)
NiCl2(dppf)
NiCl2(dppf)
3a , 97
3a , 98
(entry 2). In contrast to the palladium catalysts, nickel
0
complexes, NiCl2(PPh3)2 and NiCl2(dppf),17 showed ef-
16
0
0
0
ficient catalytic activity to provide the desired product
3a in 97% and 98% yield, respectively, after 12-16 h at
60-65 °C (entries 3 and 4). Regio- and trans olefin-
selectivities for 3a were both >99% by 1H NMR spec-
troscopy. These results suggest the presence of transient
π-allylnickel intermediate and are in agreement with that
reported for the nickel-catalyzed coupling of 3-aryl sub-
stituted allylic alcohols and their ethers with Grignard
reagents.4a,c,h,n In these experiments, methyl ether 9 was
not detected. The nickel complexes also catalyzed cou-
pling of 1a with the furylborate 4e to provide 3e
selectively in 84-88% yield (entries 8 and 9). Reactivity
of 4e was higher than that of phenylborate 4a : the
reaction was completed within 4-8 h at 45-60 °C, while
more drastic conditions (>12 h, 60-65 °C) were required
for 4a . Both nickel catalysts, NiCl2(PPh3)2 and NiCl2-
(dppf), showed an excellent catalytic activity for 4e as
well as 4a .
To survey the present reaction, organoborates 4b-f
and the carbonates 1a ,b were subjected to the reaction
in the presence of NiCl2(dppf) in THF. The results are
also shown in Table 1. Reaction of 1a with o-, m-, and
p-methoxyphenylborates 4b-d afforded the coupling
products 3b-d in good yields (entries 5-7). Coupling
with alkenylborate 4f afforded 3f in 46% yield (entry 10).
R,â-Unsaturated ester 1b also reacted with 4e to provide
γ-substituted product 3g in 67% yield (entry 11). The
last example demonstrates that the ester group can
withstand the reaction conditions. Further examples
using borate 4e (reaction with the carbonate 24) and
similar borates of the types 5 and 6 are presented later.
In all the cases examined, regio- and/or cis isomer(s) or
the methyl ether was not detected in the NMR spectra.
Cou p lin g Rea ction of 1 w ith Bor a tes 5 Der ived
fr om Acet ylen es via H yd r ob or a t ion . Since hydro-
boration of acetylenes affords stereodefined trivalent
alkenylboranes,18 combination of the hydroboration and
subsequent transformation to borates adds another ad-
vantage to the present reaction. We prepared three
3e, 84
3e, 88
0
0
10
11
0
d
a
Reactions were carried out with 2-3 equiv of 4 in the presence
of 5-10 mol % of the catalyst in THF at 45-65 °C for 4-16 h.
R1 ) Ph for 3a -f; R1 ) COOEt for 3g. R2 ) n-C5H11
.
Prepared
b
c
in situ from Pd2(dba)3‚CHCl3 and the corresponding phosphine
d
ligand. No corresponding methyl ether was produced.
the borate was explored using 11a . Among n-BuLi,
MeLi, n-BuMgBr, and MeMgI examined, MeLi provided
the best result.19 Thus, borate 5a (R4 ) n-C5H11) had
been prepared in situ by mixing 11a and 1 equiv of MeLi
in THF at 0 °C for 15 min (eq 3) and was submitted to
the reaction with the carbonate 1a in the presence of the
nickel catalyst (10 mol %, prepared from NiCl2(dppf) and
2 MeLi) in THF-MeCN20 (1:1) at 60 °C overnight to
afford the desired product 3h , regio- and stereoselec-
tively, in 70% yield (Table 2, entry 1). A similar reaction
using 10 mol % Pd(PPh3)4 in place of the nickel catalyst
gave a mixture of unidentified products.
In relation to the present reaction, Suzuki and his co-
workers have shown the coupling reactions of trivalent
alkenylboronates of type 11 and primary substrates,
3-phenylallyl phenoxide3b,k and acetate,3b in the presence
of the palladium catalysts. Since no example is given
for secondary 1,3-disubstituted allylic esters, the pos-
sibility of providing a coupling product from alkenyl-
boronate 11a with acetate 12 or carbonate 1a (eqs 5, 6)
was explored. Under Suzuki’s conditions diene 13 was
obtained in 70% yield when acetate 12 was reacted with
11a (eq 5), while a 18:82 mixture of 3a (desired product)
alkenylboronates 11a -c according to the literature
procedures11a,c and explored such a possibility. First, an
organometallic which serves as the fourth ligand to afford
(15) Bishop, J . J .; Davison, A.; Katcher, M. L.; Lichtenberg, D. W.;
Merrill, R. E.; Smart, J . C. J . Organomet. Chem. 1971, 27, 241.
(16) Venanzi, L. M. J . Chem. Soc. 1958, 719.
(17) Hayashi, T.; Konishi, M.; Yokota, K.; Kumada, M. Chem. Lett.
1980, 767.
(19) Borate derived from 11a and MeMgI afforded the diene 13,
while borates from n-BuLi or n-BuMgBr gave the reduction products
i and ii.
(18) (a) Brown, H. C.; Kramer, G. W.; Levy, A. B.; Midland, M. M.
Organic Synthesis via Boranes; Wiley: New York, 1975. (b) Brown,
H. C.; Campbell, J . B., J r. Aldrichim. Acta 1981, 14, 3. (c) Negishi, E.
In Comprehensive Organometallic Chemistry; Wilkinson, G., Stone, F.
G. A., Abel, E. W., Eds.; Pergamon: New York, 1983; Vol. 7, Chapter
45.8, p 303.
(20) Addition of MeCN resulted in somewhat better yields of the
products 3.

5394 J . Org. Chem., Vol. 61, No. 16, 1996
Kobayashi et al.
Ta ble 2. Nick el-Ca ta lyzed Cou p lin g Rea ction s of 1 a n d
5a
Ta ble 3. Nick el-Ca ta lyzed Cou p lin g Rea ction of 1a a n d
th e Cyclic Bor a tes 6a , 19-23a
borate
R4
productb
yield, %
entry borate catalystb temp, °C time, h yield of 3a ,c %
carbonate
entry
1
5
3
1
2
3
4
5
6
7
8
19
20
6a
6a
6a
21
A
A
A
A
B
A
A
A
40
35
rtd
5
12
12
4
12
4
17
15
17
95
84
88
97
87
60e
1c
2
3
1a
1a
1a
1b
5a
5b
5c
5b
n-C5H11
Ph
(CH2)2OCH2Ph
Ph
3h
3i
3j
70
87
50
86
rtd
40
65
40
4
3k
a
f,g
The catalyst (5-10 mol %) was prepared in situ from
NiCl2(dppf) and 2 equiv of MeLi before use (0 °C, 15-60 min),
22
23
<10
0
and the reactions were carried out at 50-60 °C overnight. R1 )
b
a
The borates were prepared by addition of MeLi (3 equiv) to a
Ph for 3h -j; R1 ) COOEt for 3k . R2 ) n-C5H11
.
When 10 mol
c
mixture of the corresponding boronates (4 equiv) and the nickel
% of Pd(PPh3)4 was used instead of NiCl2(dppf), a mixture of
unidentified products was obtained.
catalyst (5-10 mol %) in THF and used for the coupling reaction.
b
c
Catalyst: A ) NiCl2(dppf); B ) NiCl2(PPh3)2. R1 ) R3 ) Ph,
R2 ) n-C5H11
.
15-25 °C. (E)-3-Methyl-1-phenyl-1-octene was
f g
d
e
and 13 was produced in THF-MeCN (1:1) at 60 °C
overnight (the optimized conditions for the nickel-
catalyzed coupling). Use of carbonate 1a resulted in
production of mixtures of 3a , 13, and 10 (eq 6). In
contrast to these results, neither 10 nor 13 was detected
in the nickel-catalyzed reaction of 1a and borate 5a .
To examine the reactivity and selectivity of the borate
5 and nickel system, reaction of the allylic carbonates
1a ,b and the MeLi-derived alkenyl borates 5b,c in the
presence of NiCl2(dppf) was investigated. The results are
also summarized in Table 2. In all the cases the reactions
proceeded regio- and stereoselectively to afford 3i-k in
good to moderate yields. In no case was the correspond-
ing ethyl ether detected.
Although isolated boronates 11a -c were used to
prepare the borates 5a -c for the present reaction (Table
2), borates prepared in situ from the acetylenes can be
used directly. To give an example of a one-pot reaction,
MeLi (3 equiv) and, after 15 min at 0 °C, MeCN, the
carbonate 1a , and NiCl2(dppf) (10 mol %) were added to
a THF solution of 11b, which had been prepared in the
usual way,11c and the solution was stirred at 50-60 °C
overnight to furnish 3i in 50% isolated yield (eq 7).
coproduced in a 29% yield. Recovered 1a . Use of MeCN as
cosolvent resulted in somewhat better yield of ca. 30%.
6 (Chart 1). In the following paragraphs, we describe
the successful results of this study.
Because of the lowest reactivity of phenylborate 4a (R3
) Ph) (>12 h, 60-65 °C) (vide supra), reactions of 1a
and 3 equiv each of phenylborates 6a , 19-23 which
possess various types of diol ligands were examined first
in the presence of 5-10 mol % of NiCl2(dppf) or NiCl2-
(PPh3)2 in THF. Phenylboronates 8a ,21 14-18 were
10a,h
prepared from PhB(OH)2
and the diols according to
the literature procedures10b,d and transformed into the
borates 6a , 19-23 by addition of MeLi before use (0 °C,
15 min).
Cou p lin g Rea ction of 1 w ith Bor a tes 6 Der ived
fr om Cyclic Bor on a te Ester s 8. In the above sections
we described the nickel-catalyzed coupling of 1,3-disub-
stituted allylic carbonates 1 and aryl- or alkenylborates
4 and 5 under almost neutral conditions. However, the
reaction required a higher temperature and longer reac-
tion time and this situation could be unacceptable in
certain cases if it were utilized for the preparation of
complicated compounds. To raise the reactivity, we
decided to investigate the possibility of changing the
structure of borates. We believe that the lower reactivity
is due to the electron-withdrawing nature of the meth-
oxide ligand on 4 and, perhaps, to lower concentration
of 4 in the equilibrium10e with the corresponding trivalent
boronate. This is expected to be marginally reactive from
the study using boronates 11a (vide supra) and also 8a
(R3 ) Ph) (data not shown). This hypothesis led us to
examine a series of MeLi-derived cyclic borates such as
Reaction conditions and results are summarized in
Table 3. With 19 and 20 reactions with NiCl2(dppf)
(21) Phenylboronate ester 8a prepared from a stereoisomeric mix-
ture of 2,3-butanediols (Tokyo Kasei, J apan) was a 1:4 mixture of dl-
and meso-isomers by 1H NMR spectroscopy (signals for dl-isomer were
determined by using phenylboronate ester derived from (R,R)-2,3-
butanediol) and was used without separation. Other boronates were
mixtures of dl- and meso-isomers.

Ni-Catalyzed Coupling of Allylic Carbonates and Lithium Borates
J . Org. Chem., Vol. 61, No. 16, 1996 5395
Ta ble 4. Nick el-Ca ta lyzed Rea ction of 1a ,b a n d Cyclic
proceeded at 35-40 °C and after 12 h 3a was obtained
in high yields (entries 1, 2). Introduction of an electron-
donating methyl substituent increased the reactivity
Bor a tes 6a -f a t Room Tem p er a tu r ea
borate
R3
productb
borate carbonate time,
further (entry 3): reaction at room temperature for 4 h
furnished 3a in 88% yield. Even at lower temperature
(ca. 5 °C) 3a was obtained in good yield (entry 4).
However, the presence of four methyl groups lowered the
reactivity (entry 6), inferring severe steric hindrance in
the transmetalation with the π-allylnickel intermediate.
In the case of catechol boronate ester 17, borate formation
with MeLi was found to be different from the other
cases: an unidentified precipitation was observed and
most of 1a was recovered in the subsequent coupling
reaction (entry 7). Addition of MeCN as cosolvent
improved the yield a little. Treatment of 1a with borate
23 bearing a nitrogen-containing ligand resulted in
recovery of 1a (entry 8). In the reaction with 6a , NiCl2-
(PPh3)2 showed an almost equal reactivity with NiCl2-
(dppf) (entry 5). Palladium catalyst was totally ineffec-
tive for coupling 1a and 6a .
entry
6
precursor
1
h
3
yield, %
1
2
3
4
5
6
7
6b o-MeOC6H4
6c m-MeOC6H4
6d p-MeOC6H4
6e 2-furyl
6f C(Me)dCH2
6a Ph
8b
8c
8d
8e
8f
1a
1a
1a
1a
1a
1b
1b
12 3b
98
99
90
85
73
96
93
7
4
7
5
5
5
3c
3d
3e
3f
3l
8a
8e
6e 2-furyl
3g
a
Reactions were carried out at room temperature (15-25 °C)
in the presence of NiCl2(dppf) (5-10 mol %) in THF. R1 ) Ph
b
for 3b-f; R1 ) COOEt for 3g,l. R2 ) n-C5H11
.
To define the scope of this new system, reactions using
other combinations of allylic carbonates 1a ,b and borates
6a -f were examined next. Borate precursors 8b-f were
prepared from 2,3-butanediol and corresponding boronic
acids in a similar manner to 8a and converted to borates
6b-f with MeLi.21 The results are listed in Table 4. In
all cases reactions proceeded at room temperature and
were completed within several hours to furnish the
products 3b-g,l in high yields. As in the case of borates
4 and 5, the ester group also proved compatible with this
reagent/catalyst system (entries 6, 7). In no case, was
regio- and/or stereoisomer(s) detected in the 1H NMR
spectra of the crude products.
Ster eoch em ica l Asp ect of th e Cou p lin g Rea ction .
The stereochemistry of the present reaction was studied
by using the cyclic substrate 24 (cis/trans, >99%), which
was prepared from methyl cis-5-hydroxy-3-cyclohexene-
1-carboxylate.5c,22 The reaction was carried out by using
borates of types 4 and 6 in the presence of NiCl2(dppf)
(eq 8).
F igu r e 1. Structures and plausible conformers of trans and
cis isomers 25 and 27.
J ab ) J bc ) 12.6 Hz, J bd ) 11.2 Hz, indicating the assigned
stereochemistry and the conformation shown in Figure
1.
The same stereochemical outcome was obtained with
phenylborate 6a (eq 8). The trans stereochemistry of the
1
product 26 was assigned by comparison of the H NMR
spectrum with reported data.5c
In conclusion, we have clarified the stereochemical
aspect of the present reaction as proceeding with overall
inversion. This result indicates the “hard” nucleophilicity
of the borates.23
Mech a n ism . To understand the mechanistic aspect
of the present reaction, additional experiments were
performed. (1) When the regioisomer of 1a (i.e., 28) was
subjected to the reaction with the catecholborane-derived
borate 5b (R4 ) Ph) under the same reaction conditions
as used for 1a and 5b, the same product 3i was produced
regio- and stereoselectively in 80% yield (Scheme 1). (2)
The same sense was observed in the reaction of 28 and
the cyclic borate 6a (R3 ) Ph) (Scheme 1). (3) In all the
cases, the double bond in the product was placed regio-
selectively to conjugate with the existing π-system.
Without such a π-system, a mixture of regioisomers was
produced (eq 9) though in high yield. (4) Although Ni(II)
First, reaction with 2-furylborate 4e was performed at
55-60 °C to furnish 25 with >95% stereoisomeric purity
in 92% yield. Its stereochemistry was established to be
trans by the 300 MHz 1H NMR spectrum and by
comparison with that of cis isomer 27 which was pre-
pared by isomerization of 25 with NaOMe in MeOH.
Coupling constants of the C-6 axial hydrogen (Hb) of the
trans isomer 25 at δ 1.99 are J ab ) 11.3 Hz, J bc ) 12.8
Hz, J bd ) 5.7 Hz, and those of cis isomer 27 at δ 1.77 are
complexes were used without any pretreatment in the
series of reactions using the borates 4, the nickel(0)
complexes prepared in situ from NiCl2(dppf) and 2 equiv
of n-BuLi or MeLi also catalyzed the reaction of 1a with
4a ,e, and vice versa with 5b and 6a . In the light of the
above results, the stereochemical outcome obtained with
the cyclic substrate 24, and the facts that (π-allyl)(aryl)-
Ni complexes undergo reductive elimination to afford
(22) Trost, B. M.; Verhoeven, T. R. J . Am. Chem. Soc. 1980, 102,
4730.
(23) Keinan, E.; Roth, Z. J . Org. Chem. 1983, 48, 1769.

5396 J . Org. Chem., Vol. 61, No. 16, 1996
Kobayashi et al.
ppm) and the center line of CDCl3 triplet (δ ) 77.1 ppm) as
internal standards, respectively. The following solvents were
distilled before use: THF (from Na/benzophenone), Et2O (from
Na/benzophenone), and CH2Cl2 (from CaH2). Methyllithium
(MeLi) in Et2O and n-butyllithium (n-BuLi) in hexane were
prepared as a 0.75-1.25 M solution by the usual procedures
and stocked under a nitrogen atmosphere. Phenyllithium
(PhLi) (1.01 M in cyclohexane-Et2O) was purchased from
Kanto Chemical Co., Inc. The following nickel catalysts were
prepared according to the literature methods: NiCl2(PPh3)2,16
NiCl2(dppf).17
Sch em e 1
P r ep a r a tion s of Allylic Ca r bon a tes. (E)-3-(Eth oxy-
ca r bon yloxy)-1-p h en yl-1-octen e (1a ). To an ice cold stirred
solution of trans-cinnamaldehyde (25.2 mL, 200 mmol) in Et2O
(100 mL) was added an ethereal solution of n-C5H11MgBr (260
mL, 1.0 M in Et2O, 260 mmol) dropwise over 1 h. After 10
min, saturated NH4Cl was added, and the mixture was
extracted with hexane twice. The combined organic layers
were dried over MgSO4 and concentrated in vacuo to afford
quantitatively (E)-1-phenyl-1-octen-3-ol as a yellow oil, which
was used for the next reaction without purification: 1H NMR
δ 0.80 (t, J ) 7.1 Hz, 3 H), 1.25-1.50 (m, 6 H), 1.52-1.73 (m,
2 H), 4.28 (q, J ) 6.8 Hz, 1 H), 6.23 (dd, J ) 6.8, 16 Hz, 1 H),
6.57 (d, J ) 16 Hz, 1 H), 7.20-7.50 (m, 5 H).
Sch em e 2. P la u sible Mech a n ism of th e
Nick el-Ca ta lyzed Cou p lin g Rea ction
To an ice cold stirred solution of (E)-1-phenyl-1-octen-3-ol
(1.25 g, 6.15 mmol) in CH2Cl2 (25 mL) were added pyridine
(1.99 mL, 24.6 mmol) and ethyl chloroformate (1.18 mL, 12.3
mmol). The ice bath was removed, and the solution was stirred
overnight at room temperature. Then saturated NaHCO3 was
added, and the mixture was extracted with hexane twice. The
combined organic layers were dried over MgSO4 and concen-
trated in vacuo to afford the crude product as a brown oil.
Purification by chromatography (AcOEt/hexane) afforded 1a
(1.44 g, 85%) as a colorless oil: bp 150 °C/<0.1 Torr; 1H NMR
δ 0.88 (t, J ) 6.8 Hz, 3 H), 1.25-1.45 (m, 9 H), 1.62-1.87 (m,
2 H), 4.19 (q, J ) 7.0 Hz, 2 H), 5.21 (q, J ) 7.0 Hz, 1 H), 6.14
(dd, J ) 7.0, 16 Hz, 1 H), 6.65 (d, J ) 16 Hz, 1 H), 7.20-7.42
(m, 5 H); 13C NMR δ 154.7, 136.4, 133.1, 128.6, 128.0, 127.3,
126.7, 79.0, 63.8, 34.7, 31.6, 24.8, 22.5, 14.3, 14.0; IR (neat)
allyl-aryl products,24 it is conceivable that the reaction
did proceed as depicted in Scheme 2, a typical cycle for
the nickel catalyzed reaction:25 (1) formation of Ni(0)
complexes under the reaction conditions,26 (ii) anti oxida-
tive addition of the Ni(0) complexes to the allylic carbon-
ate 1 to produce the allyl-Ni intermediate 32, (iii)
transmetalation with the borate 2 () 4, 5, 6) and (iv) syn
reductive elimination with retention of configuration to
afford 3.
1738 cm-1
. Anal. Calcd for C17H24O3: C, 73.88; H, 8.75.
Found: C, 74.24; H, 8.82.
Eth yl (E)-4-(Eth oxyca r bon yloxy)-2-n on en oa te (1b). A
mixture of (E)-1-iodo-1-octen-3-ol27 (1.0 g, 3.9 mmol), Et3N (1.1
mL, 7.8 mmol), EtOH (1.2 mL, 20 mmol), and PdCl2(PPh3)2
(69 mg, 0.01 mmol) was stirred overnight at 62 °C under a
carbon monoxide atmosphere. Then Et2O and saturated
NH4Cl were added. The organic layer was separated and the
aqueous layer was extracted with Et2O. The combined organic
layers were dried over MgSO4 and concentrated in vacuo to
afford quantitatively ethyl (E)-4-hydroxy-2-nonenoate, which
was used for the next reaction without purification: 1H NMR
δ 0.89 (t, J ) 6.8 Hz, 3 H), 1.25-1.48 (m, 9 H), 1.54-1.66 (m,
2 H), 4.20 (q, J ) 7.0 Hz, 2 H), 4.30 (q, J ) 5.4 Hz, 1 H), 6.03
(d, J ) 15 Hz, 1 H), 6.94 (dd, J ) 5.4, 15 Hz, 1 H).
Con clu sion s
We presented new reagent/catalyst systems for cou-
pling of 1,3-disubstituted secondary allyic carbonates.
Remarkable points of the present reaction are the fol-
lowing: (1) substrate-controlled regioselection is ob-
served in all cases; (2) the reaction proceeds under mild
and almost neutral conditions; (3) borates can be pre-
pared by several methods10,11 from corresponding organo-
lithiums and B(OR)3, acetylenes, bromoacetylenes, alde-
hydes, etc.; (4) to the best of our knowledge γ-substitution
of R,â-unsaturated carbonyl compounds with the “hard”
organometallics is realized for the first time, which are
inter alia important process in organic synthesis.12 In
addition, overall inversion is secured in the cyclic sub-
strate. Prediction of the stereochemical outcome when
applied to other cyclic substrates is now possible. Reac-
tion with chiral allylic carbonates and application to
natural product synthesis will be presented in due course.
Ethyl (E)-4-hydroxy-2-nonenoate was converted to 1b in a
1
similar manner to 1a in 85% yield: bp 130 °C/<0.1 Torr; H
NMR δ 0.89 (t, J ) 6.0 Hz, 3 H), 1.23-1.48 (m, 12 H), 1.60-
1.82 (m, 2 H), 4.20 (q, J ) 7.6 Hz, 4 H), 5.21 (q, J ) 5.6 Hz, 1
H), 6.00 (d, J ) 16 Hz, 1 H), 6.83 (dd, J ) 5.6, 16 Hz, 1 H); 13
C
NMR δ 166.0, 154.5, 144.8, 122.0, 76.4, 64.2, 60.6, 33.9, 31.5,
24.5, 22.5, 14.3, 14.0; IR (neat) 1745, 1725 cm-1. Anal. Calcd
for C14H24O5: C, 61.74; H, 8.88. Found: C, 61.71; H, 9.09.
Met h yl cis-5-(E t h oxyca r b on yloxy)-3-cycloh exen e-1-
ca r b oxyla t e (24). Methyl cis-5-hydroxy-3-cyclohexene-1-
carboxylate was prepared according to the procedure of Trost22
and converted to 24 in a similar manner to 1a in 57% overall
Exp er im en ta l Section
Gen er a l Meth od s. Infrared (IR) spectra are reported in
wave numbers (cm-1). 1H NMR (300 MHz) and 13C NMR (75
MHz) spectra were measured in CDCl3 using SiMe4 (δ ) 0
1
yield: bp 150 °C/<0.1 Torr; H NMR δ 1.32 (t, J ) 7.5 Hz, 3
H), 1.83 (dt, J ) 9.2, 12 Hz, 1 H), 2.28-2.35 (m, 2 H), 2.40-
2.49 (m, 1 H), 2.73 (ddt, J ) 2.9, 12, 7.7 Hz, 1 H), 3.70 (s, 3 H),
4.21 (q, J ) 7.5 Hz, 1 H), 5.21-5.30 (m, 1 H), 5.71 (d, J ) 10
Hz, 1 H), 5.89 (ddt, J ) 1.7, 10, 3.4 Hz, 1 H); 13C NMR δ 174.4,
154.7, 129.6, 126.3, 72.7, 63.9, 51.9, 37.7, 30.5, 27.2, 14.3; IR
(neat) 1736, 1253 cm-1. Anal. Calcd for C11H16O5: C, 57.89;
H, 7.07. Found: C, 58.04; H, 7.21.
(24) Stoichiometric reaction of π-allylnickels with ArMgBr (Ar )
aromatic) and subsequent reductive elimination has been reported:
Kurosawa, H.; Ohnishi, H.; Emoto, M.; Chatani, N.; Kawasaki, Y.;
Murai, S.; Ikeda, I. Organometallics 1990, 9, 3038.
(25) Consiglio, G.; Morandini, F.; Piccolo, O. J . Am. Chem. Soc. 1981,
103, 1846. See also ref 4h and 4n.
(26) Tamao, K.; Sumitani, K.; Kumada, M. J . Am. Chem. Soc. 1972,
94, 4374. (b) Baba, S.; Negishi, E. J . Am. Chem. Soc. 1976, 98, 6729.
(27) Luo, F.-T.; Negishi, E. J . Org. Chem. 1985, 50, 4762.

Ni-Catalyzed Coupling of Allylic Carbonates and Lithium Borates
J . Org. Chem., Vol. 61, No. 16, 1996 5397
(E)-1-(Eth oxyca r bon yloxy)-1-p h en yl-2-octen e (28). To
an ice cold stirred solution of (E)-2-octenal (1.5 mL, 10 mmol)
in Et2O (10 mL) was added PhLi (12 mL, 12 mmol) dropwise
over 10 min. After 10 min, saturated NH4Cl was added, and
the mixture was extracted with hexane twice. The combined
organic layers were concentrated in vacuo to afford quantita-
tively (E)-1-phenyl-2-octen-1-ol as a yellow oil, which was used
for the next reaction without purification: 1H NMR δ 0.88 (t,
J ) 6.7 Hz, 3 H), 1.28-1.50 (m, 6 H), 1.50-1.72 (m, 2 H), 4.27
(q, J ) 6.3 Hz, 1 H), 6.23 (dd, J ) 6.3, 16 Hz, 1 H), 6.56 (d, J
) 16 Hz, 1 H), 7.17-7.42 (m, 5 H).
mL) over 30 min at -78 °C. Stirring was continued for 1 h at
-78 °C, and the solution was warmed up to room temperature
over 2 h. Then 3 N HCl was added, and the mixture was
extracted with AcOEt twice. The combined organic layers
were dried over MgSO4 and concentrated in vacuo to afford
the crude boronic acid as a solid, which was transformed to
the boronate ester directly in a similar manner to method C.
4,5-Dim eth yl-2-p h en yl-1,3,2-d ioxa bor ola n e (8a ):10b,28a
yield 100% by method C; bp 90 °C/1 Torr; 1H NMR δ 1.28 and
1.40 (2d (4:1), J ) 7.5 and 7.5 Hz, 6 H), 4.12-4.22 and 4.65-
4.77 (2m (1:4), 2 H), 7.33-7.50 (m, 3 H), 7.82 (d, J ) 7.5 Hz,
2 H).
4,5-Dim e t h yl-2-(2-m e t h oxyp h e n yl)-1,3,2-d ioxa b or o-
la n e (8b): yield 41% by method E; bp 130 °C/1 Torr; 1H NMR
δ 1.31 and 1.41 (2d (2:1), J ) 4.7 and 4.7 Hz, 6 H), 3.77 (s, 3
H), 4.14-4.25 and 4.64-4.76 (2m (1:2), 2 H), 6.89 (d, J ) 5.2
Hz, 1 H), 6.97 (t, J ) 4.7 Hz, 1 H), 7.42 (t, J ) 5.2 Hz, 1 H),
7.74 (d, J ) 4.7 Hz, 1 H); IR (neat) 1601, 1578 cm-1. Anal.
Calcd for C11H15BO3: C, 64.12; H, 7.34. Found: C, 63.54;
H, 7.60.
(E)-1-Phenyl-2-octen-1-ol was converted to 28 in a similar
1
manner to 1a in 88% yield: bp 150 °C/<0.1 Torr; H NMR δ
0.88 (t, J ) 6.8 Hz, 3 H), 1.22-1.47 (m, 9 H), 1.62-1.90 (m, 2
H), 4.20 (q, J ) 7.1 Hz, 2 H), 5.22 (q, J ) 7.4 Hz, 1 H), 6.15
(dd, J ) 7.4, 16 Hz, 1 H), 6.65 (d, J ) 16 Hz, 1 H), 7.22-7.45
(m, 5 H); 13C NMR δ 154.7, 136.3, 133.1, 128.6, 128.0, 127.3,
126.7, 79.0, 63.8, 34.7, 31.6, 24.8, 22.5, 14.3, 14.0; IR (neat)
1741 cm-1
. Anal. Calcd for C17H24O3: C, 73.88; H, 8.75.
Found: C, 73.59; H, 8.74.
(2E,6E)-1-(Eth oxyca r bon yloxy)-3,7,11-tr im eth yl-2,6,10-
d od eca tr ien e (29). The title compound was prepared from
farnesol in a similar manner to 1a in 85% yield: bp 130 °C/
<0.1 Torr; 1H NMR δ 1.29 (t, J ) 7.5 Hz, 3 H), 1.53-1.73 (m,
12 H), 1.82-2.17 (m, 8 H), 4.18 (q, J ) 7.5 Hz, 2 H), 4.63 (d,
J ) 7.5 Hz, 2 H), 5.03-5.15 (m, 2 H), 5.38 (t, J ) 7.5 Hz, 1 H);
13C NMR δ 155.3, 143.1, 135.5, 131.3, 124.4, 123.6, 117.9, 64.5,
63.8, 39.7, 39.6, 26.8, 26.2, 25.7, 17.7, 16.5, 16.0, 14.3; IR (neat)
4,5-Dim e t h yl-2-(3-m e t h oxyp h e n yl)-1,3,2-d ioxa b or o-
la n e (8c): yield 52% by method E; bp 130 °C/1 Torr; 1H NMR
δ 1.29 and 1.40 (2d (4:1), J ) 8.0 and 8.0 Hz, 6 H), 3.83 (s, 3
H), 4.13-4.24 and 4.65-4.77 (2m (1:4), 2 H), 7.01 (ddd, J )
1.7, 3.3, 10 Hz, 1 H), 7.24-7.34 (m, 2 H), 7.41 (d, J ) 10 Hz,
1 H); IR (neat) 1573 cm-1
. Anal. Calcd for C11H15BO3: C,
64.12; H, 7.34. Found: C, 64.12; H, 7.64.
4,5-Dim e t h yl-2-(4-m e t h oxyp h e n yl)-1,3,2-d ioxa b or o-
la n e (8d ): yield 61% by method E; bp 130 °C/1 Torr; 1H NMR
δ 1.29 and 1.39 (2d (5:1), J ) 8.3 and 8.3 Hz, 6 H), 3.82 (s, 3
H), 4.10-4.20 and 4.61-4.73 (2m (1:5), 2 H), 6.90 (d, J ) 11
1743 cm-1
. Anal. Calcd for C18H30O3: C, 73.43; H, 10.27.
Found: C, 73.38; H, 10.49.
P r ep a r a tion s of Bor on a te Ester s. Meth od A. To a
stirred solution of catecholborane (4.8 mL, 45 mmol) in benzene
(7.5 mL) were added acetylene (45 mmol) and RhCl(PPh3)3 (21
mg, 0.022 mmol). After stirring for 1.5 h at room temperature,
the solution was concentrated in vacuo, and the residue was
distilled at reduced pressure to afford 11.
Hz, 2 H), 7.75 (d, J ) 11 Hz, 2 H); IR (neat) 1741, 1606 cm-1
.
Anal. Calcd for C11H15BO3: C, 64.12; H, 7.34. Found: C,
65.33; H, 7.35.
4,5-Dim eth yl-2-(2-fu r yl)-1,3,2-d ioxa bor ola n e (8e): yield
1
62% by method D; bp 80 °C/1 Torr; H NMR δ 1.30 and 1.40
Meth od B. To an ice cold stirred suspension of NaH (4.32
g, 50% content in mineral oil, 90 mmol) in THF (100 mL) was
added 3-butyn-1-ol (2.27 mL, 30 mmol) dropwise over 10 min.
After 10 min, benzyl bromide (10.7 mL, 90 mmol) and
dimethylformamide (6.87 mL, 90 mmol) were added. The ice
bath was removed and the mixture was stirred for 3 h at room
temperature. Then saturated NH4Cl was added, and the
mixture was extracted with hexane twice. The combined
organic layers were dried over MgSO4 and concentrated in
vacuo to afford the crude product as an oil. Purification by
chromatography (hexane) and distillation under reduced pres-
sure (70 °C/1 Torr) afforded 1-(benzyloxy)-3-butyne (4.42 g,
92%) as a colorless oil: 1H NMR δ 2.01 (t, J ) 2.6 Hz, 1 H),
2.52 (dt, J ) 5.3, 7.5 Hz, 2 H), 3.62 (t, J ) 7.5 Hz, 2 H), 4.58
(s, 2 H), 7.25-7.42 (m, 5 H).
(2d (3:1), J ) 8.3 and 8.3 Hz, 6 H), 4.15-4.24 and 4.65-4.76
(2m (1:3), 2 H), 6.46 (dd, J ) 2.7, 4.3 Hz, 1 H), 7.09 (d, J ) 4.3
Hz, 1 H), 7.68 (d, J ) 2.7 Hz, 1 H); IR (neat) 1574, 1097 cm-1
.
Anal. Calcd for C8H11BO3: C, 57.89; H, 6.68. Found: C,
57.45; H, 6.75.
4,5-Dim e t h yl-2-(1-m e t h yle t h e n yl)-1,3,2-d ioxa b or o-
la n e (8f): yield 61% by method E; bp 80 °C/15 Torr; 1H NMR
δ 1.23 and 1.32 (2d (7:3), J ) 6.0 and 6.0 Hz, 6 H), 1.83 (s, 3
H), 4.00-4.10 and 4.52-4.64 (2m (3:7), 2 H), 5.66 (s, 1 H), 5.77
(s, 1 H); IR (neat) 1619 cm-1. Anal. Calcd for C7H13BO2: C,
60.06; H, 9.36. Found: C, 59.80; H, 9.47.
2-[(E)-1-Hep ten yl]-1,3,2-ben zod ioxa bor ole (11a ):29 yield
61% by method A; bp 90 °C/<0.1 Torr; 1H NMR δ 0.90 (t, J )
6.8 Hz, 3 H), 1.25-1.38 (m, 4 H), 1.42-1.58 (m, 2 H), 2.22-
2.30 (m, 2 H), 5.78 (d, J ) 18 Hz, 1 H), 6.98-7.12 (m, 3 H),
7.17-7.26 (m, 2 H).
1-(Benzyloxy)-3-butyne was converted to the boronate ester
11c in a similar manner to method A.
Meth od C. To a stirred suspension of phenylboronic
acid10a,h (2.0 g, 16 mmol) in benzene (50 mL) were added the
diol (16 mmol) and MgSO4 (10 g). The mixture was stirred
overnight at room temperature and filtered. The filtrate was
concentrated in vacuo to afford the crude product as an oil.
Purification by chromatography (AcOEt/hexane) and distilla-
tion under reduced pressure afforded the phenylboronate ester
as a colorless oil.
Meth od D. To an ice cold stirred solution of furan (2.17
mL, 30 mmol) in THF (50 mL) was added n-BuLi (30 mmol)
over 30 min. After 2 h, the solution was added to B(O-i-Pr)3
(6.9 mL, 30 mmol) dissolved in Et2O (100 mL) over 30 min at
-78 °C. Stirring was continued for 1 h at -78 °C, and the
solution was warmed up to room temperature over 2 h. Then
3 N HCl was added, and the mixture was extracted with
AcOEt twice. The combined organic layers were dried over
MgSO4 and concentrated in vacuo to afford the crude boronic
acid as a solid, which was transformed to the boronate ester
8e directly in a similar manner to method C.
2-[(E)-2-P h en yleth en yl]-1,3,2-ben zod ioxa bor ole (11b):
yield 58% by method A; bp 130 °C/<0.1 Torr; H NMR δ
6.48 (d, J ) 19 Hz, 1 H), 7.10 (dd, J ) 3.8, 7.5 Hz, 2 H), 7.26
(dd, J ) 3.8, 7.5 Hz, 2 H), 7.32-7.45 (m, 3 H), 7.49 (d, J ) 7.5
Hz, 2 H), 7.78 (d, J ) 19 Hz, 1 H).
2-[(E )-4-(B e n zy lo x y )-1-b u t e n y l]-1,3,2-b e n zo d io x a -
bor ole (11c): yield 57% by method B; bp 155 °C/<0.1 Torr;
1H NMR δ 2.61 (q, J ) 5.5 Hz, 2 H), 3.62 (t, J ) 5.5 Hz, 2 H),
4.55 (s, 2 H), 5.89 (d, J ) 11 Hz, 1 H), 6.99-7.11 (m, 3 H),
7.17-7.39 (m, 7 H); IR (neat) 3051, 1646 cm-1. Anal. Calcd
for C17H17BO3: C, 72.89; H, 6.12. Found: C, 72.92; H, 6.20.
2-P h en yl-1,3,2-d ioxa bor in a n e (14):28a,b yield 100% by
method C; bp 90 °C/1 Torr; 1H NMR δ 2.00-2.10 (m, 2 H),
4.15 (t, J ) 5.6 Hz, 4 H), 7.30-7.43 (m, 3 H), 7.77 (d, J ) 7.5
Hz, 2 H).
18a
1
(28) (a) Bowie, R. A.; Musgrave, O. C. J . Chem. Soc. 1963, 3945. (b)
Lauer, M.; Wulff, G. J . Chem. Soc., Perkin Trans. 2 1987, 745. (c)
Ko¨nig, T.; Ma¨nnel, D.; Habicher, W. D.; Schwetlick, K. Polym. Degrad.
Stab. 1988, 22, 137. (d) Hoffmann, R. W.; Bewersdorf, M.; Kru¨ger, M.;
Mikolaiski, W.; Stu¨rmer, R. Chem. Ber. 1991, 124, 1243.
(29) Baeckstro¨m, P.; J acobsson, U.; Norin, T.; Unelius, C. R.
Tetrahedron 1988, 44, 2541.
Meth od E. To a stirred solution of the aryl or alkenyl
bromide (30 mmol) in THF (50 mL) was added n-BuLi (30
mmol) over 30 min at -78 °C. After 2 h, the solution was
added to B(O-i-Pr)3 (6.9 mL, 30 mmol) dissolved in Et2O (100

5398 J . Org. Chem., Vol. 61, No. 16, 1996
Kobayashi et al.
2-P h en yl-1,3,2-d ioxa bor ola n e (15):28a-c yield 100% by
method C; bp 80 °C/1 Torr; 1H NMR δ 4.38 (s, 4 H), 7.30-7.50
(m, 3 H), 7.82 (d, J ) 7.5 Hz, 2 H).
126.2, 120.7, 110.9, 55.6, 41.7, 35.1, 31.9, 27.4, 22.6, 14.1; IR
(neat) 1600 cm-1. Anal. Calcd for C21H26O: C, 85.66; H, 8.90.
Found: C, 86.10; H, 8.30.
2-P h en yl-4,4,5,5-tetr a m eth yl-1,3,2-d ioxa bor ola n e (16):
(E)-3-(3-Meth oxyp h en yl)-1-p h en yl-1-octen e (3c): yield
81% by method C and 99% by method E; bp 180 °C/<0.1 Torr;
1H NMR δ 0.85 (t, J ) 5.7 Hz, 3 H), 1.17-1.43 (m, 6 H), 1.71-
1.83 (m, 2 H), 3.38 (q, J ) 7.2 Hz, 1 H), 3.81 (s, 3 H), 6.30 (dd,
J ) 7.2, 16 Hz, 1 H), 6.40 (d, J ) 16 Hz, 1 H), 6.70-6.87 (m,
3 H), 7.10-7.38 (m, 6 H); 13C NMR δ 159.8, 146.6, 137.7, 134.4,
129.5, 129.4, 128.5, 127.0, 126.2, 120.1, 113.7, 111.2, 55.2, 49.3,
35.9, 31.9, 27.4, 22.6, 14.1; IR (neat) 1595, 1255 cm-1. Anal.
Calcd for C21H26O: C, 85.66; H, 8.90. Found: C, 84.97, H,
9.19.
(E)-3-(4-Meth oxyp h en yl)-1-p h en yl-1-octen e (3d ): yield
89% by method C and 90% by method E; bp 180 °C/<0.1 Torr;
1H NMR δ 0.86 (t, J ) 6.6 Hz, 3 H), 1.18-1.40 (m, 6 H), 1.68-
1.82 (m, 2 H), 3.35 (q, J ) 7.3 Hz, 1 H), 3.79 (s, 3 H), 6.29 (dd,
J ) 7.3, 16 Hz, 1 H), 6.37 (d, J ) 16 Hz, 1 H), 6.82-6.89 (m,
2 H), 7.12-7.36 (m, 7 H); 13C NMR δ 158.0, 137.8, 136.9, 134.9,
129.0, 128.6, 128.5, 127.0, 126.2, 113.9, 55.3, 48.3, 36.0, 31.9,
27.4, 22.7, 14.2; IR (neat) 1613, 1248 cm-1. Anal. Calcd for
28d
yield 100% by method C; bp 100 °C/1 Torr; 1H NMR δ 1.34
(s, 12 H), 7.32-7.50 (m, 3 H), 7.81 (d, J ) 7.5 Hz, 2 H).
2-P h en yl-1,3,2-ben zod ioxa bor ole (17):28c yield 100% by
1
method C; bp 100 °C/<0.1 Torr; H NMR δ 7.14 (dd, J ) 4.3,
7.7 Hz, 2 H), 7.32 (dd, J ) 4.3, 7.7 Hz, 2 H), 7.46-7.62 (m, 3
H), 8.09 (d, J ) 8.3 Hz, 2 H).
Gen er a l P r oced u r es for Cou p lin g Rea ction s. Meth od
A. To an ice cold stirred solution of B(OMe)3 (112 mg, 1.08
mmol) in THF (3 mL) was added PhLi (0.80 mL, 0.81 mmol)
dropwise over 5 min under a nitrogen atmosphere. After 15
min, the ice bath was removed, and the solution was warmed
up to room temperature. The carbonate (0.27 mmol) and the
nickel catalyst (0.027 mmol) were added, and the solution was
stirred overnight at 60-65 °C. Then saturated NaHCO3 was
added, and the mixture was extracted with hexane twice. The
combined organic layers were dried over MgSO4 and concen-
trated in vacuo to afford the crude product as a brown oil.
Purification by chromatography (AcOEt/hexane) afforded the
coupling product as a colorless oil.
Meth od B. To an ice cold stirred solution of furan (73.5
mg, 1.08 mmol) in THF (3 mL) was added n-BuLi (0.81 mmol)
dropwise over 5 min under a nitrogen atmosphere. The
solution was stirred at 0 °C for 2 h, and then B(OMe)3 (112
mg, 1.08 mmol) was added. After 15 min, the ice bath was
removed and the solution was warmed up to room tempera-
ture. The carbonate (0.27 mmol) and the nickel catalyst (0.027
mmol) were added, and the solution was stirred at 45-60 °C
for 4-13 h. Workup and purification in a similar manner to
method A afforded the coupling product.
Meth od C. To a stirred solution of the aryl or alkenyl
bromide (0.81 mmol) in THF (3 mL) was added n-BuLi (1.08
mmol) dropwise over 10 min under a nitrogen atmosphere at
-78 °C. The solution was stirred at -78 °C for 2 h, and then
B(OMe)3 (112 mg, 1.08 mmol) was added. After 15 min, the
cooling bath was removed, and the solution was warmed up
to room temperature. The carbonate (0.27 mmol) and the
nickel catalyst (0.027 mmol) were added, and the solution was
stirred overnight at 60-65 °C. Workup and purification in a
similar manner to method A afforded the coupling product.
Meth od D. To an ice cold stirred suspension of the nickel
catalyst (0.036 mmol) in THF (2 mL) was added MeLi (0.072
mmol) under a nitrogen atmosphere. The solution was stirred
at 0 °C for 15-60 min, and then the alkenyl boronate ester
(1.44 mmol) and MeLi (1.08 mmol) were added. After 15 min,
the ice bath was removed and the solution was warmed up to
room temperature. The carbonate (0.36 mmol) and MeCN (2
mL) were added, and the solution was stirred overnight at 50-
60 °C. Workup and purification in a similar manner to method
A afforded the coupling product.
Meth od E. To an ice cold stirred suspension of the boronate
ester (1.08 mmol) and the nickel catalyst (0.027 mmol) in THF
(3 mL) was added MeLi (0.81 mmol) dropwise over 5 min under
a nitrogen atmosphere. After 15 min, (the ice bath was
removed and the solution was warmed up to room temperature
for the reaction at >room temperature) the carbonate (0.27
mmol) was added, and the solution was stirred at 5-65 °C for
4-15 h. Workup and purification in a similar manner to
method A afforded the coupling product.
C21
H26O: C, 85.66; H, 8.90. Found: C, 85.20; H, 8.99.
(E)-3-(2-F u r yl)-1-p h en yl-1-octen e (3e): yield 88% by
method B and 85% by method E; bp 150 °C/<0.1 Torr; 1H NMR
δ 0.87 (t, J ) 6.4 Hz, 3 H), 1.24-1.44 (m, 6 H), 1.58-1.94 (m,
2 H), 3.51 (q, J ) 7.6 Hz, 1 H), 6.04 (d, J ) 2.5 Hz, 1 H), 6.22
(dd, J ) 7.6, 16 Hz, 1 H), 6.29-6.32 (dd, J ) 1.3, 2.5 Hz, 1 H),
6.42 (d, J ) 16 Hz, 1 H), 7.15-7.39 (m, 6 H); 13C NMR δ 157.7,
141.1, 137.4, 131.2, 130.6, 128.5, 127.2, 126.3, 110.1, 104.7,
42.8, 33.8, 31.8, 27.0, 22.6, 14.1; IR (neat) 1715 cm-1. Anal.
Calcd for C18H22O: C, 84.99; H, 8.72. Found: C, 85.06; H,
8.81.
(E)-3-(1-Meth yleth en yl)-1-p h en yl-1-octen e (3f): yield
46% by method C and 73% by method E; bp 80 °C/<0.1 Torr;
1H NMR δ 0.88 (t, J ) 6.6 Hz, 3 H), 1.22-1.41 (m, 6 H), 1.43-
1.65 (m, 2 H), 1.72 (s, 3 H), 2.79 (q, J ) 7.5 Hz, 1 H), 4.79 (d,
J ) 4.5 Hz, 2 H), 6.12 (dd, J ) 7.5, 15 Hz, 1 H), 6.37 (d, J )
15 Hz, 1 H), 7.15-7.40 (m, 5 H); 13C NMR δ 147.9, 137.9, 133.5,
129.7, 128.5, 127.0, 126.1, 110.5, 50.7, 32.9, 32.0, 27.2, 22.7,
20.2, 14.2; IR (neat) 1642 cm-1. Anal. Calcd for C17H24
89.41; H, 10.59. Found: C, 88.72; H, 10.77.
: C,
Eth yl (E)-4-(2-F u r yl)-2-n on en oa te (3g): yield 67% by
method B and 93% by method E; bp 150 °C/<0.1 Torr; 1H NMR
δ 0.87 (t, J ) 6.7 Hz, 1 H), 1.20-1.38 (m, 9 H), 1.62-1.90 (m,
2 H), 3.51 (q, J ) 7.5 Hz, 1 H), 4.18 (q, J ) 7.5 Hz, 2 H), 5.81
(d, J ) 15.7 Hz, 1 H), 6.06 (d, J ) 3.2 Hz, 1 H), 6.31 (dd, J )
2.0, 3.2 Hz, 1 H), 6.95 (dd, J ) 7.5, 15.7 Hz, 1 H), 7.14 (d, J )
2.0 Hz, 1 H); 13C NMR δ 166.5, 155.4, 148.8, 141.6, 121.9,
110.2, 105.6, 60.4, 41.9, 33.0, 31.6, 26.9, 22.5, 14.3, 14.0; IR
(neat) 1720, 1650 cm-1. Anal. Calcd for C15H22O3: C, 71.97;
H, 8.86. Found: C, 71.79; H, 9.27.
(1E,4E)-3-P en tyl-1-ph en yl-1,4-decadien e (3h ): yield 70%
by method D; bp 150 °C/<0.1 Torr; 1H NMR δ 0.87 (t, J ) 6.0
Hz, 6 H), 1.20-1.40 (m, 12 H), 1.96-2.08 (m, 4 H), 2.73-2.85
(m, 1 H), 5.36 (dd, J ) 6.0, 16 Hz, 1 H), 5.43 (dt, J ) 6.0, 16
Hz, 1 H), 6.12 (dd, J ) 7.0, 16 Hz, 1 H), 6.32 (d, J ) 16 Hz, 1
H), 7.15-7.40 (m, 5 H); 13C NMR δ 138.0, 134.5, 132.9, 130.6,
128.9, 128.5, 126.9, 126.1, 46.1, 35.4, 32.7, 32.0, 31.5, 29.3, 27.1,
22.7, 22.6, 14.2; IR (neat) 1600 cm-1; MS m/ e (rel intensity,
%) 284 (M+, 86), 227 (54), 214 (33), 157 (97), 144 (84), 141 (50),
128 (80), 117 (98), 115 (100), 109 (49), 43 (50), 41 (56). Anal.
Calcd for C21H32
11.91.
: C, 88.66; H, 11.34. Found: C, 88.56; H,
(E)-1,3-Dip h en yl-1-octen e (3a ): yield 98% by method A
1
and 88-97% by method E; bp 170 °C/<0.1 Torr; H NMR δ
(E)-1-P h en yl-3-[(E)-2-ph en yleth en yl]-1-octen e (3i): yield
1
0.88 (t, J ) 5.6 Hz, 3 H), 1.19-1.42 (m, 6 H), 1.72-1.88 (m, 2
H), 3.39 (q, J ) 7.5 Hz, 1 H), 6.32 (dd, J ) 7.5, 15 Hz, 1 H),
6.39 (d, J ) 15 Hz, 1 H), 7.12-7.39 (m, 10 H); 13C NMR δ
144.8, 137.7, 134.6, 129.3, 128.5, 127.7, 127.1, 126.2, 49.3, 36.0,
31.9, 27.4, 22.6, 14.2; IR (neat) 3040, 1598 cm-1. Anal. Calcd
87% by method D; bp 190 °C/<0.1 Torr; H NMR δ 0.86 (t, J
) 6.0 Hz, 3 H), 1.20-1.40 (m, 6 H), 1.56-1.62 (m, 2 H), 2.96-
3.07 (m, 1 H), 6.19 (dd, J ) 7.5, 16 Hz, 2 H), 6.41 (d, J ) 16
Hz, 2 H), 7.15-7.39 (m, 10 H); 13C NMR δ 137.8, 133.4, 129.7,
128.6, 127.1, 126.2, 46.5, 35.3, 32.0, 27.1, 22.7, 14.2; IR (neat)
1598 cm-1; MS m/ e (rel intensity, %) 290 (M+, 79), 220 (94),
206 (100), 205 (78), 204 (51), 191 (51), 141 (52), 129 (72), 128
for C20H24
: C, 90.85; H, 9.15. Found: C, 91.34; H, 8.97.
(E)-3-(2-Meth oxyp h en yl)-1-p h en yl-1-octen e (3b): yield
86% by method C and 98% by method E; bp 180 °C/<0.1 Torr;
1H NMR δ 0.85 (t, J ) 7.6 Hz, 3 H), 1.19-1.42 (m, 6 H), 1.68-
1.81 (m, 2 H), 3.83 (s, 3 H), 3.88 (q, J ) 7.5 Hz, 1 H), 6.31-
6.44 (m, 2 H), 6.84-6.96 (m, 2 H), 7.12-7.37 (m, 7 H); 13C NMR
δ 157.1, 138.1, 134.3, 133.3, 129.2, 128.4, 127.9, 127.0, 126.8,
(60), 117 (55), 115 (71), 91 (67). Anal. Calcd for C22H26
90.98; H, 9.02. Found: C, 91.14; H, 8.83.
: C,
(E)-1-(Ben zyloxy)-5-[(E)-2-ph en yleth en yl]-3-decen e (3j):
yield 50% by method D; bp 280 °C/<0.1 Torr; 1H NMR δ 0.86
(t, J ) 6.0 Hz, 3 H), 1.20-1.50 (m, 8 H), 2.32-2.43 (m, 2 H),

Ni-Catalyzed Coupling of Allylic Carbonates and Lithium Borates
J . Org. Chem., Vol. 61, No. 16, 1996 5399
2.76-2.87 (m, 1 H), 3.51 (t, J ) 6.0 Hz, 2 H), 4.51 (s, 2 H),
5.40-5.55 (m, 2 H), 6.11 (dd, J ) 7.5, 16 Hz, 1 H), 6.34 (d, J
) 16 Hz, 1 H), 7.15-7.40 (m, 10 H); 13C NMR δ 138.7, 137.9,
135.1, 134.1, 129.1, 128.5, 128.4, 127.7, 127.5, 126.9, 126.4,
126.1, 72.9, 70.3, 46.2, 35.2, 33.2, 31.9, 27.0, 22.7, 14.2; IR
(neat) 1681 cm-1; MS m/ e (rel intensity, %) 348 (M+, 6), 277
(42), 257 (99.5), 240 (99.9), 213 (55), 171 (55), 169 (100), 155
(56), 143 (95), 129 (91), 117 (98), 115 (51), 105 (55), 92 (71), 91
(72). Anal. Calcd for C25H32O: C, 86.15; H, 9.25. Found: C,
85.39; H, 9.70.
E t h yl (E)-4-[(E)-2-P h en ylet h en yl]-2-n on en oa t e (3k ):
yield 86% by method D; bp 180 °C/<0.1 Torr; 1H NMR δ 0.88
(t, J ) 5.6 Hz, 3 H), 1.18-1.40 (m, 9 H), 1.46-1.62 (m, 2 H),
2.94-3.06 (m, 1 H), 4.17 (q, J ) 7.5 Hz, 2 H), 5.85 (d, J ) 16
Hz, 1 H), 6.06 (dd, J ) 7.5, 16 Hz, 1 H), 6.39 (d, J ) 16 Hz, 1
H), 6.94 (dd, J ) 7.5, 16 Hz, 1 H), 7.17-7.40 (m, 5 H); 13C
NMR δ 166.7, 151.1, 137.2, 131.1, 130.9, 128.6, 127.4, 126.2,
120.9, 60.3, 45.8, 34.4, 31.8, 26.9, 22.6, 14.3, 14.1; IR (neat)
1723 cm-1; MS m/ e (rel intensity, %) 286 (M+, 97), 257 (99.5),
241 (87), 216 (48), 215 (61), 214 (61), 213 (42), 212 (70), 195
(90), 187 (58), 182 (72), 170 (65), 169 (58), 167 (100), 157 (75),
156 (70), 155 (97), 144 (47), 142 (56), 129 (87), 128 (83), 117
(62), 115 (85), 112 (74), 91 (61). Anal. Calcd for C19H26O2: C,
79.68; H, 9.15. Found: C, 79.21; H, 9.41.
27. Cis Isom er 27: 1H NMR δ (diagnostic peaks) 1.77 (dt, J
) 11.2, 12.6 Hz, 1 H), 2.36-2.45 (m, 1 H), 6.02 (dt, J ) 3.4,
0.8 Hz, 1 H), 7.32 (dd, J ) 0.8, 1.9 Hz, 1 H).
Met h yl tr a n s-5-P h en yl-3-cycloh exen e-1-ca r b oxyla t e
(26): yield 95% by method E and the following 1H NMR
spectra were in good agreement with those reported for trans
isomer:5c 1H NMR δ 1.98 (dt, J ) 13, 3.8 Hz, 1 H), 2.17 (ddd,
J ) 6.2, 11, 13 Hz, 1 H), 2.31-2.40 (m, 2 H), 2.61 (ddt, J )
3.8, 6.2, 9.4 Hz, 1 H), 3.52-3.61 (m, 1 H), 3.65 (s, 3 H), 5.78
(d, J ) 13 Hz, 1 H), 5.95 (d, J ) 13 Hz, 1 H), 7.17-7.35 (m, 5
H).
(6E)-1-P h en yl-3,7,11-tr im eth yl-2,6,10-d od eca tr ien e (30)
a n d (6E)-3-P h en yl-3,7,11-tr im eth yl-1,6,10-d od eca tr ien e
(31): yield 96% by method E; bp 150 °C/<0.1 Torr; 3:1 mixture
1
of 30:31; H NMR δ 1.37-1.72 (m, 9 H), 1.92-2.16 (m, 8 H),
3.35 (d, J ) 7.5 Hz, 2 H for 30), 5.01-5.16 (m, 2 H for 30 and
4 H for 31), 5.34 (t, J ) 7.5 Hz, 1 H for 30), 6.04 (dd, J ) 11,
18 Hz, 1 H for 31), 7.12-7.62 (m, 5 H); IR (neat) 1491 cm-1
.
Anal. Calcd for C21H30
H, 10.57.
: C, 89.30; H, 10.70. Found: C, 88.94;
Th r ee-Step On e P ot Rea ction . To a stirred solution of
catecholborane (1.44 mL, 1.0 M in THF, 1.44 mmol) were
added phenylacetylene (110 mg, 1.08 mmol) and RhCl(PPh3)3
(6.7 mg, 0.0072 mmol) under a nitrogen atmosphere. The
solution was stirred at room temperature for 1 h and cooled
at 0 °C, and MeLi was added (1.08 mmol) over 5 min. After
15 min, the ice bath was removed, and the solution was
warmed up to room temperature. The carbonate 1a (99.5 mg,
0.36 mmol), MeCN (2 mL), and NiCl2(dppf) (24.6 mg, 0.036
mmol) were added, and the solution was stirred at 50-60 °C
overnight. Then saturated NaHCO3 was added, and the
mixture was extracted with hexane twice. The combined
organic layers were dried over MgSO4 and concentrated in
vacuo to afford the crude product as a brown oil. Purification
by chromatography (AcOEt/hexane) afforded 3i (52 mg, 50%)
as a colorless oil.
Eth yl (E)-4-P h en yl-2-n on en oate (3l): yield 96% by method
1
E; bp 160 °C/<0.1 Torr; H NMR δ 0.85 (t, J ) 6.3 Hz, 3 H),
1.17-1.35 (m, 9 H), 1.66-1.83 (m, 2 H), 3.38 (q, J ) 7.5 Hz, 1
H), 4.17 (q, J ) 7.3 Hz, 2 H), 5.77 (d, J ) 16 Hz, 1 H), 7.06
(dd, J ) 7.5, 16 Hz, 1 H), 7.14-7.35 (m, 5 H); 13C NMR δ 166.7,
152.0, 142.5, 128.7, 127.8, 126.7, 120.7, 60.3, 48.6, 35.0, 31.7,
27.2, 22.5, 14.3, 14.1; IR (neat) 1721 cm-1. Anal. Calcd for
C17H24O2: C, 78.42; H, 9.29. Found: C, 78.11; H, 9.39.
Meth yl tr a n s-5-(2-F u r yl)-3-cycloh exen e-1-ca r boxyla te
1
(25): yield 92% by method B; H NMR δ 1.99 (ddd, J ) 5.7,
11.3, 12.8 Hz, 1 H), 2.20 (dt, J ) 12.8, 3.2 Hz, 1 H), 2.24-2.38
(m, 2 H), 2.64 (dddd, J ) 3.2, 5.7, 9.5, 11.3 Hz, 1 H), 3.56-
3.63 (m, 1 H), 3.67 (s, 3 H), 5.75-5.83 (m, 1 H), 5.84-5.92 (m,
2 H), 5.99 (dt, J ) 3.2, 1.0 Hz, 1 H), 6.28 (dt, J ) 3.2, 2.1 Hz,
1 H), 7.34 (dd, J ) 1.0, 2.1 Hz, 1 H); 13C NMR δ 175.9, 157.3,
141.5, 127.2, 126.1, 110.0, 105.9, 51.7, 35.7, 33.7, 29.8, 27.5;
Ack n ow led gm en t. We are grateful to Kuraray for
a generous supply of all-trans-farnesol and to Dr. N.
Hara of Fujimoto Lab., Tokyo Institute of Technology,
for mass spectral data.
IR (neat) 1732, 1173 cm-1
. Anal. Calcd for C12H14O3: C,
69.89; H, 6.84. Found: C, 69.60; H, 6.92.
For comparison, product 25 was treated with a catalytic
amount of NaH in MeOH to give a mixture of 25 and cis isomer
J O960458C