1
64
J . Org. Chem. 2000, 65, 164-168
P a lla d iu m -Ca ta lyzed Bor yla tion of Ar yl Ha lid es or Tr ifla tes w ith
Dia lk oxybor a n e: A Novel a n d F a cile Syn th etic Rou te to
Ar ylbor on a tes
Miki Murata, Takashi Oyama, Shinji Watanabe, and Yuzuru Masuda*
Department of Materials Science, Kitami Institute of Technology, Kitami 090-8507, J apan
Received August 24, 1999
A direct borylation of aryl halides or triflates with dialkoxyborane was investigated. The coupling
reaction of pinacolborane with aryl halides or triflates in the presence of a catalytic amount of
PdCl
2
(dppf) together with a base provided arylboronates in high yields. The product distributions
N, was effective
were strongly dependent on the base employed, and the tertiary amine, especially Et
3
for the selective formation of the boron-carbon bond. The reaction conditions were so mild that
arylboronates having a variety of functional groups such as carbonyl, cyano, and nitro groups were
readily prepared.
In tr od u ction
direct borylation of aryl halides or pseudo-halides has
been expected to be a more convenient procedure for
preparing arylboronates. Thus, Miyaura and co-workers
reported on a palladium-catalyzed cross-coupling reaction
of tetraalkoxydiboron, which provided a one-step proce-
dure for deriving organoboronates from organic electro-
philes.10
Arylboronic acids and their esters are valuable re-
agents in organic synthesis,1 and much attention has
-3
4
been paid to them in biology and in the study of
molecular recognition.5 Ordinarily, arylboron com-
pounds can be prepared by the transmetalation between
arylmagnesium or -lithium reagents and boron com-
pounds that have good leaving groups such as the
,6
Recently, Kunai and his colleague have found that the
PdCl
afforded Et
2
-catalyzed reaction of alkyl iodides with Et
2 2
SiH
7
halogen or alkoxy group. In a few cases, this synthesis
ISi-R to some extent,11 indicating the po-
2
has been conducted by the use of boron compounds
tential use of metal hydride as a metalating reagent in
the presence of a palladium catalyst. More recently, we
have developed each palladium-catalyzed selective meta-
containing a boron-hydrogen bond.8 On one hand, the
,9
(
1) (a) Miyaura, N.; Yanagi, T.; Suzuki, A. Synth. Commun. 1981,
1, 513. (b) Watanabe, T.; Miyaura, N.; Suzuki, A. Synlett 1992, 207.
c) Huth, A.; Beetz, I.; Schumann, I. Tetrahedron 1989, 45, 6679. (d)
Fu, J .-m.; Snieckus, V. Tetrahedron Lett. 1990, 31, 1665. (e) Shieh,
W.-C.; Carlson, J . A. J . Org. Chem. 1992, 57, 379. (f) Oh-e, T.; Miyaura,
N.; Suzuki, A. J . Org. Chem. 1993, 58, 2201. (g) Ishiyama, T.; Kizaki,
H.; Hayashi, T.; Suzuki, A.; Miyaura, N. J . Org. Chem. 1998, 63, 4726.
1
2
1
(
lations of aryl halides utilizing trialkoxysilanes and
13
dialkoxyboranes as metalating reagents. Thus, the
latter novel palladium-catalyzed coupling reaction of
dialkoxyhydroborane 2 with aryl halides 1 afforded the
13,14
corresponding arylboronates 3 in high yield (eq 1).
In
(
h) For a recent review for palladium-catalyzed cross-coupling reactions
of arylboronates, see: Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95,
2
1
(c) Saito, S.; Oh-tani, S.; Miyaura, N. J . Org. Chem. 1997, 62, 8024.
d) Ueda, M.; Saito, A.; Miyaura, N. Tetrahedron 1998, 54, 13079.
(
(3) (a) Ishihara, K.; Mouri, M.; Gao, Q.; Maruyama, T.; Furuta, K.;
Yamamoto, H. J . Am. Chem. Soc. 1993, 115, 11490. (b) Ishihara, K.;
Kurihara, H.; Yamamoto, H. J . Am. Chem. Soc. 1996, 118, 3049. (c)
Ishihara, K.; Ohara, S.; Yamamoto, H. J . Org. Chem. 1996, 61, 4196.
(
d) Ishihara, K.; Inanaga, K.; Kondo, S.; Funahashi, M.; Yamamoto,
H. Synlett 1998, 1053.
4) For a recent review for boron neutron capture therapy, see:
(
Soloway, A. H.; Tjarks, W.; Barnum, B. A.; Rong, F.-G.; Barth, R. F.;
Wyzlic, I. M.; Wilson, J . G. Chem. Rev. 1998, 98, 1515.
this paper, we describe in detail the scope and limitation
(
5) (a) Wulff, C.; Heide, B.; Helfmeier, G. J . Am. Chem. Soc. 1986,
1
08, 1089. (b) Nagai, Y.; Kobayashi, K.; Toi, H.; Aoyama, Y. Bull. Chem.
(8) Breuer, S. W.; Thorpe, F. G.; Podest a´ , J . C. Tetrahedron Lett.
1974, 3719, and references therein.
Soc. J pn. 1993, 66, 2965. (c) Mohler, L. H., Czarnik, A. W. J . Am. Chem.
Soc. 1993, 115, 2998. (d) Westmark, P. R.; Smith, B. D. J . Am. Chem.
Soc. 1994, 116, 9343. (e) J ames, T. D.; Sandnayake, K. R. A. S.; Iguchi,
R.; Shinkai, S. J . Am. Chem. Soc. 1995, 117, 8982. (f) For a recent
review for boronic acid receptors for saccharides, see: J ames, T. D.;
Linnane, P.; Shinkai, S. Chem. Commun. 1996, 281.
(9) Brown, H. C.; Rogic, M. M. J . Am. Chem. Soc. 1969, 91, 4304.
(10) (a) Ishiyama, T.; Murata, M.; Miyaura, N. J . Org. Chem. 1995,
60, 7508. (b) Ishiyama, T.; Itoh, Y.; Kitano, T.; Miyaura, N. Tetrahedron
Lett. 1997, 38, 3447. (c) Ishiyama, T.; Ahiko, T.-a.; Miyaura, N.
Tetrahedron Lett. 1996, 37, 6889. (d) Ahiko, T.-a.; Ishiyama, T.;
Miyaura, N. Chem. Lett. 1997, 811.
(6) (a) Reetz, M. T.; Niemer, C. M.; Harmes, M.; Goddard, R. Angew.
Chem., Int. Ed. Engl. 1992, 31, 1017. (b) Nozaki, K.; Tsutsumi, T.;
Takaya, H. J . Org. Chem. 1995, 60, 6668. (c) Nozaki, K.; Yoshida, M.;
Takaya, H. Bull. Chem. Soc. J pn. 1996, 69, 2043.
(11) Kunai, A.; Sakurai, T.; Toyoda, E.; Ishikawa, M.; Yamamoto,
Y. Organometallics 1994, 13, 3233.
(12) Murata, M.; Suzuki, K.; Watanabe, S.; Masuda, Y. J . Org.
Chem. 1997, 62, 8569.
(
7) (a) Matteson, D. S. In The Chemistry of the Metal-Carbon Bond;
Hartley, F. R., Patai, S., Eds.; Wiley: New York, 1987; Vol. 4, p 307.
b) Vaultier, M.; Carboni, B. In Comprehensive Organometallic Chem-
(13) The preliminary communication of this work has been re-
ported: Murata, M.; Watanabe, S.; Masuda, Y. J . Org. Chem. 1997,
62, 6458.
(
istry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon:
Oxford, 1995; Vol. 11, p 191. (c) Miyaura, N.; Maruoka, K. In Synthesis
of Organometallic Compounds; Komiya, S., Ed.; Wiley: New York,
(14) The versatility of this borylation13 was demonstrated for the
synthesis of porphyrins. See: Hyslop, A. G.; Kellett, M. A.; Iovine, P.
M.; Therien, M. J . J . Am. Chem. Soc. 1998, 120, 12676.
1
997; p 345.
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0.1021/jo991337q CCC: $19.00 © 2000 American Chemical Society
Published on Web 12/17/1999