Parallel Synthesis of a Library of Benzoxazoles and Benzothiazoles Using Ligand-Accelerated Copper-Catalyzed Cyclizations of ortho-Halobenzanilides
Ghotas Evindar and Robert A. Batey*
*Department of Chemistry, University of Toronto, 80 St. George Street,
Toronto, Ontario, Canada M5S 3H6, Email: rbatey
chem.utoronto.ca
G. Evindar, R. A. Batey, J. Org. Chem., 2006, 71, 1802-1808.
DOI: 10.1021/jo051927q
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Abstract
A general method for the formation of benzoxazoles and benzothiazoles via a copper-catalyzed
cyclization of ortho-haloanilides is reported. Optimal conditions for
cyclization used a catalyst combination of CuI and 1,10-phenanthroline as ligand.
The mechanism is believed to proceed via an
oxidative insertion/reductive elimination pathway through a Cu(I)/Cu(III)
manifold. The rate of reaction of ortho-haloanilides follows the order I >
Br > Cl, consistent with oxidative addition being the rate-determining step.
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proposed mechanism
R. D. Viirre, G. Evindar, R. A. Batey, J. Org. Chem., 2008, 73, 3452-3459.
Key Words
ID: J42-Y2006-610
