Silver-Catalyzed Asymmetric Sakurai−Hosomi Allylation of Ketones

Manabu Wadamoto and Hisashi Yamamoto*
Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637
J. Am. Chem. Soc., 2005, 127 (42), pp 14556–14557
DOI: 10.1021/ja0553351
Publication Date (Web): September 30, 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.

, yamamoto@uchicago.edu

Abstract

Abstract Image

The complex of AgF and (R)-DIFLUORPHOS has been shown to be an effective catalyst for the asymmetric Sakurai−Hosomi allylation of simple ketones. A significaant improvement of the reactivity was observed by using THF as the solvent. The catalyst turnover was increased by addition of 1 equiv of MeOH. AgF and (R)-DIFLUORPHOS predominantly formed a 1:1 complex that provided high enantioselectivity. This catalyst system can be applied to various simple ketones, and corresponding tertiary homoallylic alcohols were obtained with excellent enantioselectivities (up to 96% ee). Only 1,2-adducts were obtained from both acyclic and cyclic conjugate ketones. The regio-, diastereo-, and enantioselective crotylation has also been achieved. E- or Z-crotyltrimethoxysilane gave a similar diastereomer ratio with high enantioselectivities. This finding introduces the utility of racemic allylsilanes for the enantioselective Sakurai−Hosomi allylation reaction.

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History

  • Published In Issue October 26, 2005
  • Received August 5, 2005

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