Novel palladium-catalyzed diarylation and dialkenylation reactions of norbornene derivatives

Article abstract of DOI:10.1055/s-1998-1710

Norbornene and its derivatives are diarylated or dialkenylated by aryl- or alkenyltributylstannanes, a palladium catalyst, and chloroacetone or chloroacetonitrile as a reoxidant.

Full text of DOI:10.1055/s-1998-1710

May 1998
SYNLETT
477
Novel Palladium-Catalyzed Diarylation and Dialkenylation Reactions of Norbornene
Derivatives
Keigo Fugami, Sachiko Hagiwara, Hiroshi Oda, and Masanori Kosugi*
Department of Chemistry, Gunma University, Kiryu, Gunma 376-8515, JAPAN
FAX +81-277-30-1285; e-mail: kosugi@chem.gunma-u.ac.jp
Received 20 January 1998
Abstract: Norbornene and its derivatives are diarylated or
dialkenylated by aryl- or alkenyltributylstannanes, a palladium catalyst,
and chloroacetone or chloroacetonitrile as a reoxidant.
homocoupling of the alkenylstannanes. To suppress its formation, the
use of an excess of norbornene was inevitable (runs 2-5 and 8), while a
stoichiometric amount of norbornene was enough in the diarylation
(
0
runs 1,6,7, and 9). The amount of chloroacetone could be reduced to
.55 mol equiv to the stannane without lowering the yield (run 5).
Transition metal catalyzed ternary coupling reaction, i.e., insertion of
alkynes or alkenes into a cross–coupling reaction, is one of the recent
1
interests. Insertion of alkynes or alkenes into a homocoupling reaction
2
,3
is considered to be included in a similar category.
We recently
reported palladium-catalyzed stereoselective difunctionalization
a
reaction of some internal alkynes by organotributylstannanes using
4
copper(II) chloride as a reoxidant. In this reaction, however, only
limited internal alkynes (diphenylacetylene and acetylenedicarboxylate)
and aryltributylstannanes were tolerable. Alkenyl- and alkynyl-
tributylstannanes did not give the addition products at all, in this
reaction. In 1993, Kikukawa et al. reported the oxidative homocoupling
of organostannanes using chloroacetone or chloroacetophenone as a
5
reoxidant. We attempted to employ chloroacetone as a reoxidant for
our difunctionalization reaction and found that norbornene and its
derivatives could be difunctionalized by alkenylstannanes as well as
arylstannanes. We report here our results.
To a tetrahydrofuran (THF) solution of dichlorobis(benzonitrile)pal-
ladium(II) (0.1 mmol) and triphenylphosphine (0.15 mmol) were added
tributylphenylstannane (2.2 mmol), chloroacetone (4.0 mmol), and
norbornene (1.0 mmol), successively. The resulting yellow solution was
stirred at 50 °C for 29 h. The resulting brown mixture was diluted with
hexane and washed with aqueous ammonium fluoride solution. The
organic layer was washed with water, dried over anhydrous sodium
sulfate, and concentrated to about 10 mL. The residual colorless
solution was passed through a short silica gel column using hexane as
the eluent. The elute was concentrated and the residual oil was subjected
to silica gel column chromatography to provide exo-cis-2,3-
diphenylbicyclo[2.2.1]heptane in 58% yield. The representative results
are summarized in Table 1. Exo-cis products were the predominant or
exclusive products in all cases. None of other isomers could be isolated.
Chloroacetonitrile could be employed as a reoxidant as well as
chloroacetone (run 2), whereas the following halides were not effective
at all; bromoacetone, bromoacetonitrile, carbon tetrachloride, carbon
tetrabromide, and chloroform. The alkenylations with (E)-
alkenylstannanes were stereospecific, although not perfect, giving the
2
,3-dialkenylbicyclo[2.2.1]heptanes mainly with retention of the
geometries. The minor products if formed were the corresponding E,Z-
isomers. On the other hand, the reaction of (Z)-tributylstannylacrylate
was interesting. The main product was exo-cis-2-[(Z)-
methoxycarbonylethenyl]-3-[(E)-methoxycarbonylethenyl]bicyclo-
[
2.2.1]heptane and exo-cis-(Z,Z)-2,3-bis(2-methoxycarbonylethenyl)-
Diphenylation was examined with some norbornene derivatives.
Benzonorbornene was diphenylated to afford the desired adduct in a
moderate yield (run 6). On the other hand, the reaction of
benzooxanorbornene resulted in monophenylation along with the ring
bicyclo[2.2.1]heptane was not detected at all (run 3). Isomerization
alkenylstannanes was never observed in any case. In every case, the
major byproduct was an 1,3-butadiene derivative formed via the direct

4
78
LETTERS
SYNLETT
cleavage to give 1,2-dihydro-2-phenyl-1-naphthol as a sole product (run
6877 (1994); H. Oda, K. Ito, M. Kosugi, and T. Migita, Chem.
Lett., 1994, 1443; F. Ozawa, Y. Kobatake, A. Kubo, and T.
Hayashi, J. Chem. Soc., Chem. Commun., 1994, 1323; R. C.
Larock, Y. Wang, Y.-de Lu, and C. E. Russell, J. Org. Chem., 59,
8107 (1994); H. Oda, T. Kobayashi, M. Kosugi, and T. Migita,
Tetrahedron, 51, 695 (1995); N. Chatani, N. Amishiro, T. Morii,
T. Yamashita, and S. Murai, J. Org. Chem., 60, 1834 (1995); H.
Oda, K. Hamataka, K. Fugami, M. Kosugi, and T. Migita, Synlett,
1995, 1225; References cited therein.
6
9
).
Interestingly,
the
reaction
of
dimethyl
exo-cis-7-
oxabicyclo[2.2.1]hept-2-ene-5,6-dicarboxylate afforded the desired
diarylated product and dialkenylated product, although the yields were
not high, without giving the corresponding ring-opened side products, at
all.
In our previous report, some internal alkynes were diarylated when
copper(II) was a reoxidant, while norbornene derivatives could neither
4
be diarylated nor dialkenylated. On the other hand, with the present
system, not only norbornenes but also diphenylacetylene could be
diphenylated, although the yield was not as high as that in the copper
case (eq 2). Attempts to dialkenylate alkynes failed, however.
2
S.-i. Ikeda, H. Yamamoto, K. Kondo, and Y. Sato,
Organometallics, 14, 5015 (1995); J. Montgomery, J. Seo, and H.
M. P. Chui, Tetrahedron Lett., 37, 6839 (1996); S.-i. Ikeda, K.
Kondo, and Y. Sato, J. Org. Chem., 61, 8248 (1996); H.
Nakamura, J.-G. Shim, and Y. Yamamoto, J. Am Chem. Soc., 119,
7
8
11 (1997); R. Grigg and R. Pratt, Tetrahedron Lett., 38, 4489
(
1997); R. Grigg, S. Brown, V. Sridharan, and M. Uttley,
Tetrahedron Lett., 38, 5031 (1997); References cited therein.
3
Some interesting homocoupling reactions have been reported,
recently: J.-i. Yoshida, K. Tamao, T. Kakui, and M. Kumada,
Tetrahedron Lett., 1979, 1141; K. A. Smith, E. M. Campi, W. R.
Jackson, S. Marcuccio, C. G. M. Naeslund, and G. B. Deacon,
Synlett, 1997, 131; E. Shirakawa, Y. Murota, Y. Nakao, and T.
Hiyama, Synlett, 1997, 1143; S. Yamaguchi, S. Ohno, and K.
Tamao, Synlett, 1997, 1199.
The present results suggest that choice of the reoxidant may alter the
applicable pair of the substrates. Exploitation of other effective oxidants
for further applicability and investigations of the reaction mechanism
are now under way.
References and Notes
1
D. D. Bender, F. G. Stakem, and R. F. Heck, J. Org. Chem., 47,
278 (1982); M. Ahmar, J.-J. Barieux, B. Bazes, and J. Goré,
4
5
H. Oda, M. Morishita, K. Fugami, H. Sano, and M. Kosugi, Chem.
Lett., 1996, 811.
1
Tetrahedron, 43, 513 (1987); M. Kosugi, H. Tamura, H. Sano, and
T. Migita, Tetrahedron, 45, 961 (1989); N. Kopola, B. Friess, B.
Cazes, and J. Goré, Tetrahedron Lett., 30, 3963 (1989); N.
Chaptal, V. Colovray-Gotteland, C. Grandjean, B. Cazes, and J.
Goré, Tetrahedron Lett., 32, 1795 (1991); N. Chatani, N.
Amishiro, and S. Murai, J. Am. Chem. Soc., 113, 7778 (1991); M.
Kosugi, T. Kimura, H. Oda, and T. Migita, Bull. Chem. Soc. Jpn.,
K. Kikukawa, M. Kariya, Y. Shin’ya, A. Takata, and K.
Kamemoto, 7th IUPAC Symposium on Organo-Metallic
Chemistry directed towards Organic Synthesis, Kobe, Japan
(
1993), 163A.
6
7
C. Moinet, J.-C. Fiaud, Tetrahedron Lett., 36, 2051 (1995).
The reaction at 50 °C for 3 d resulted in the formation of 20%
yield of the desired product accompanied with a mixture of
intractable byproducts.
6
5
6, 3522 (1993); S. Ikeda and Y. Sato, J. Am. Chem. Soc., 116,
975 (1994); S. Ikeda, D.-M. Cui, and Y. Sato, J. Org. Chem., 59,