ORGANIC
LETTERS
2
004
Vol. 6, No. 16
809-2811
Dabco as an Inexpensive and Highly
Efficient Ligand for Palladium-Catalyzed
Suzuki−Miyaura Cross-Coupling
Reaction
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Jin-Heng Li* and Wen-Jie Liu
Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research,
College of Chemistry and Chemical Engineering, Hunan Normal UniVersity,
Changsha 410081, China
Received June 10, 2004
ABSTRACT
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An inexpensive and highly efficient Pd(OAc) /Dabco catalytic system has been developed for the cross-coupling of aryl halides with arylboronic
acids. A combination of Pd(OAc) and Dabco (triethylenediamine) was observed to form an excellent catalyst, which affords high TONs (turnover
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numbers; TONs up to 950 000 for the reaction of PhI and p-chlorophenylboronic acid) for Suzuki−Miyaura cross-coupling of various aryl
iodides and bromides with arylboronic acids.
c,4-6
Biaryls are versatile intermediates in organic synthesis and
a recurring functional group in many natural products and
bioactive compounds. As a result, considerable effort has
Miyaura cross-coupling reaction.2
However, phosphine
ligands are sensitive to air, which places significant limits
on their synthetic applications. Therefore, the development
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been directed toward the development of efficient and
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-11
selective methods for the synthesis of biaryls.
The
(
5) For recent representative papers on phosphine-palladium catalysts,
see: (a) Old, D. W.; Wolfe, J. P.; Buchwald, S. L. J. Am. Chem. Soc. 1998,
20, 9722. (b) Wolfe, J. P.; Singer, R. A.; Yang, B. H.; Buchwald, S. L. J.
Suzuki-Miyaura cross-coupling reaction represents one of
the most widely used processes for the synthesis of
Phosphine ligands are generally used to com-
plex and activate the palladium species, and excellent results
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Am. Chem. Soc. 1999, 121, 9550. (c) Littke, A. F.; Dai, C.; Fu, G. C. J.
Am. Chem. Soc. 2000, 122, 4020. (d) Bedford, R. B.; Cazin C. S. J.;
Hazelwood, S. L. Angew. Chem., Int. Ed. 2002, 41, 4120. (e) Feuerstein,
M.; Berthiol, F.; Doucet, H.; Santelli, M. Synlett 2002, 1807. (f) Mori, K.;
Yamaguchi, K.; Hara, T.; Mizugaki, T.; Ebitani, K.; Kaneda, K. J. Am.
Chem. Soc. 2002, 124, 11572. (g) Yin, J.; Rainka, M. P.; Zhang, X.-X.;
Buchwald, S. L. J. Am. Chem. Soc. 2002, 124, 1162. (h) Littke, A. F.;
Schwarz, L.; Fu, G. C. J. Am. Chem. Soc. 2002, 124, 6343. (i) Littke, A.
F.; Fu, G. C. Angew. Chem., Int. Ed. 2002, 41, 4176.
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c,4-11
biaryls.
have been reported for the palladium-catalyzed Suzuki-
(
1) Bringmann, G.; Gunther, C.; Ochse, M.; Schupp, O.; Tasler, S. In
Progress in the Chemistry of Organic Natural Products; Herz, W., Falk,
H., Kirby, G. W., Moore, R., E., Eds.; Springer: New York, 2001; Vol.
8
2, pp 1-293.
(6) (a) Pignolet, L. H., Ed. Homogeneous Catalysis with Metal Phosphine
Complexes; Plenum: New York, 1983. (b) Parshall, G. W.; Ittel, S.
Homogeneous Catalysis; J. Wiley and Sons: New York, 1992.
(7) For recent reviews on N-heterocyclic carbene-palladium catalysts,
see: (a) Herrmann, W. A. Angew. Chem., Int. Ed. 2002, 41, 1290. (b) Yong,
B. S.; Nolan, S. P. Chemtracts: Org. Chem. 2003, 205.
(
2) (a) Bringmann, G.; Walter, R.; Weirich, R. Angew. Chem., Int. Ed.
Engl. 1990, 29, 977. (b) Hegedus, L. S. In Oranometallics in Synthesis;
Schlosser, M., Ed.; J. Wiley and Sons: Chichester, 2002; p 1123. (c)
Handbook of Organopalladium Chemistry for Organic Synthesis; Negishi,
E., Ed.; Wiley-Interscience: New York, 2002.
(
3) For Ullmann coupling reactions, see: (a) Zhang, S.; Zhang, D.;
(8) For recent representative papers on thiourea-palladium catalysts,
see: (a) Dai, M.; Liang, B.; Wang, C.; Chen, J.; Yang, Z. Org. Lett. 2004,
6, 221. (b) Yang, D.; Chen, Y.-C.; Zhu, N.-Y. Org. Lett. 2004, 6, 1577.
(9) For recent representative papers on diazabutadiene-palladium cata-
lysts, see: (a) Grasa, G. A.; Hillier, A. C.; Nolan, S. P. Org. Lett. 2001, 3,
1077. (b) Palencia, H.; Garcia-Jimenez, F.; Takacs, J. M. Tetrahedron Lett.
2004, 45, 3849.
Liebeskind, L. S. J. Org. Chem. 1997, 62, 2312. (b) Li, J.-H.; Xie, Y.-X.;
Yin, D.-L. J. Org. Chem. 2003, 68, 9867 and references cited therein.
(
4) For reviews, see: (a) Miyaura, N.; Suzuki, A. Chem. ReV. 1995, 95,
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457. (b) Diederich, F.; Stang, P. J. Metal-Catalyzed Cross-Coupling
Reactions; Wiley-VCH: Weinheim, 1998. (c) Miyaura, N. Cross-Coupling
Reaction; Springer: Berlin, 2002.
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0.1021/ol048907f CCC: $27.50 © 2004 American Chemical Society
Published on Web 07/08/2004