Lewis Base Activation of Lewis Acids. Vinylogous Aldol Addition Reactions of Conjugated N,O-Silyl Ketene Acetals to Aldehydes

Scott E. Denmark* and John R. Heemstra, Jr.
Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801
J. Am. Chem. Soc., 2006, 128 (4), pp 1038–1039
DOI: 10.1021/ja056747c
Publication Date (Web): January 6, 2006
Copyright © 2006 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

N,O-Silyl dienyl ketene acetals derived from unsaturated morpholine amides have been developed as highly useful reagents for vinylogous aldol addition reactions. In the presence of SiCl4 and the catalytic action of chiral phosphoramide (R,R)-3, N,O-silyl dienyl ketene acetal 8 undergoes high-yielding and highly site-selective addition to a wide variety of aldehydes with excellent enantioselectivity. Of particular note is the high yields and selectivities obtained from aliphatic aldehydes. Low catalyst loadings (2−5 mol %) can be employed. The morpholine amide serves as a useful precursor for further synthetic manipulation.

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History

  • Published In Issue February 01, 2006
  • Received October 2, 2005

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