Asymmetric Intermolecular C−H Functionalization of Benzyl Silyl Ethers Mediated by Chiral Auxiliary-Based Aryldiazoacetates and Chiral Dirhodium Catalysts

Huw M. L. Davies,* Simon J. Hedley, and Brooks R. Bohall
Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000
J. Org. Chem., 2005, 70 (26), pp 10737–10742
DOI: 10.1021/jo051747g
Publication Date (Web): November 17, 2005
Copyright © 2005 American Chemical Society
*

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

, hdavies@acsu.buffalo.edu

Abstract

Abstract Image

C−H functionalization of benzyl silyl ethers by means of rhodium-catalyzed insertions of aryldiazoacetates can be achieved in a highly diastereoselective and enantioselective manner by judicious choice of chiral catalyst or auxiliary. The dirhodium tetraprolinates such as Rh2((S)-DOSP)4 have been widely successful as chiral catalysts in the C−H functionalization chemistry of aryldiazoacetates, but give poor enantioselectivity in the reactions of aryldiazoacetates with benzyl silyl ether derivatives. The use of (S)-lactate as a chiral auxiliary resulted in C−H functionalization with moderately high diastereoselectivity (79−88% de) and enantioselectivity (68−85% ee). The best results (91−95% de, 95−98% ee), however, were achieved using Hashimoto's Rh2((S)-PTTL)4 catalyst.

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History

  • Published In Issue December 23, 2005
  • Received August 18, 2005

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