ORGANIC
LETTERS
1
999
Vol. 1, No. 2
99-301
A New Transformation of Silanols.
Palladium-Catalyzed Cross-Coupling
with Organic Halides in the Presence of
Silver(I) Oxide
2
Kazunori Hirabayashi, Jun Kawashima, Yasushi Nishihara, Atsunori Mori,* and
Tamejiro Hiyama†
Research Laboratory of Resources Utilization, Tokyo Institute of Technology,
Nagatsuta, Yokohama 226-8503, Japan
Received April 22, 1999
ABSTRACT
The reactions of aryl- and alkenylsilanols with organic halides are found to proceed in a catalyst system of 5 mol % of Pd(PPh
1 equiv) to give the corresponding coupling products in up to 84% yield.
3 4 2
) and Ag O
(
Little attention has been paid to synthetic utilization of
silanols, since syntheses and isolation of silanols are con-
sidered to be difficult due to their instability to moisture,
heat, acid, and base. We have recently reported a facile
synthesis of silanols that possess a functional group by
alkylative cleavage of a cyclic siloxane with organolithium
reagents.1 Functional group transformations of the obtained
silanols are also documented: cyclopropanation of alkenyl-
silanols, for example, under the conditions of the Simmons-
The cross-coupling reaction is a facile method to form a
carbon-carbon bond using various organometallic reagents
and organic electrophiles. Organosilicon compounds have
also been revealed to undergo the cross-coupling reaction.4
However, the coupling of arylsilanes, for example, requires
the use of organosilanes with two fluorine atoms as substit-
,2
5,6
uents and of a fluoride ion as an activator. Hence, an
(3) Synthetic utilization of silanols, see also: (a) Chan, T. H.; Chen, L.
M.; Wang, D. J. Chem. Soc., Chem. Commun. 1988, 1280-1281. (b) Chan,
T. H.; Chen, L. M.; Wang, D.; Li, L. H. Can. J. Chem. 1993, 71, 60-67.
2 2 2
Smith reaction using Et Zn-CH I is accelerated as observed
with allylic alcohols.1
,3
(c) Yamamoto, K.; Kawanami, Y.; Miyazawa, M. J. Chem. Soc., Chem.
Our continuing interest has been focused on transformation
of a carbon-silicon bond of a silanol to a carbon-carbon
bond. We herein describe that cross-coupling of silanols with
Commun. 1993, 436-437. (d) Li, L. H.; Chan, T. H. Tetrahedron Lett.
1
997, 38, 101-104. (e) Takaku, K.; Shinokubo, H.; Oshima, K. Tetrahedron
Lett. 1996, 37, 6781-6784. (f) Takaku, K.; Shinokubo, H.; Oshima, K.
Tetrahedron Lett. 1997, 38, 5189-5192. (g) Uehara, S.; Takaku, H.;
Shinokubo, K.; Oshima, K. Synlett 1998, 1096-1098. (h) Trost, B. M.;
Ito, N.; Greenspan, P. D. Tetrahedron Lett. 1993, 34, 1421-1424. (i)
Soderquist, J. A.; Vaquer, J.; Diaz, M. J.; Rane, A. M.; Bordwell, F. G.;
Zhang, S. Tetrahedron Lett. 1996, 37, 2561-2564. (j) Akiyama, T.; Imazeki,
S. Chem. Lett. 1997, 1077-1078.
(4) (a) Hiyama, T.; Hatanaka, Y. Pure Appl. Chem. 1994, 66, 1471-
1478. (b) Mowery, M. E.; DeShong, P. J. Org. Chem. 1999, 64, 1684-
1688.
organic halides is realized by the addition of Ag
2
O as an
activator.
†
Department of Material Chemistry, Graduate School of Engineering,
Kyoto University, Yoshida, Kyoto 606-8501, Japan.
(
1) (a) Hirabayashi, K.; Mori, A.; Hiyama, T. Tetrahedron Lett. 1997,
3
8, 461-464. (b) Hirabayashi, K.; Takahisa, E.; Nishihara, Y.; Mori, A.;
Hiyama, T. Bull. Chem. Soc. Jpn. 1998, 71, 2409-2417. See also: (c) Mori,
A.; Hishida, T.; Soga, Y.; Kawakami, Y. Chem. Lett. 1995, 107-108. (d)
Mori, A.; Sato, H.; Mizuno, K.; Hiyama, T.; Shintani, K.; Kawakami, Y.
Chem. Lett. 1996, 517-518.
(5) Coupling reaction of PhSiF3, PhSi(alkyl)F2, or PhSi(Me)2F with
4-iodoacetophenone afforded the corresponding coupling product in 0%
(24 h), 68-87% (12 h), or 15% (24 h) yield, respectively: Hatanaka, Y.;
Fukushima, S.; Hiyama, T. Chem. Lett. 1989, 1711-1714.
(6) In the reaction of an alkenylsilane, by contrast, the monofluorosilane,
alkenyl(dimethyl)fluorosilane, is also effective along with alkenyl(methyl)-
difluorosilane: Hatanaka, Y.; Hiyama, T. J. Org. Chem. 1989, 54, 268-
270.
(
2) (a) Sieburth, S. M.; Mu, W.J. Org. Chem. 1993, 58, 7584-7586. (b)
Sieburth, S. M.; Fensterbank, L. J. Org. Chem. 1993, 58, 6314-6318. For
a review on silanols, see: (c) Lickiss, P. D. AdV. Inorg. Chem. 1995, 42,
1
47-262.
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0.1021/ol990614c CCC: $18.00 © 1999 American Chemical Society
Published on Web 05/27/1999