Lewis Base Activation of Lewis Acids. Vinylogous Aldol Reactions

Scott E. Denmark* and Gregory L. Beutner
Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801
J. Am. Chem. Soc., 2003, 125 (26), pp 7800–7801
DOI: 10.1021/ja035448p
Publication Date (Web): June 7, 2003
Copyright © 2003 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.

, denmark@scs.uiuc.edu

Abstract

Abstract Image

A highly regioselective vinylogous aldol reaction catalyzed by SiCl4 and a chiral phosphoramide (R,R)-5, providing δ-hydroxy enones for a variety of aldehyde and dienol ether structures, has been developed. Low catalyst loadings (1 mol %) can be employed, giving the products in good yields, excellent enantioselectivities, and in some cases excellent anti diastereoselectivities. Both simple ester-derived dienol ethers as well as dioxanone-derived dienol ethers are employed. The observed regioselectivity is rationalized in terms of the sensitivity of the catalyst to the steric demands of the nucleophile.

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History

  • Published In Issue July 02, 2003
  • Received April 3, 2003

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