A Highly Efficient Organocatalyst for Direct Aldol Reactions of Ketones with Aldedydes

Zhuo Tang, Zhi-Hua Yang,† Xiao-Hua Chen, Lin-Feng Cun, Ai-Qiao Mi, Yao-Zhong Jiang, and Liu-Zhu Gong*
Contribution from the Key Laboratory for Asymmetric Synthesis and Chirotechnology of Sichuan Province, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, 610041, China, and Graduate School of Chinese Academy of Sciences, Beijing, China
J. Am. Chem. Soc., 2005, 127 (25), pp 9285–9289
DOI: 10.1021/ja0510156
Publication Date (Web): June 4, 2005
Copyright © 2005 American Chemical Society
†

 Visiting scholar from Sichuan University.

,
*

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

, gonglz@cioc.ac.cn

Abstract

Abstract Image

l-Proline amides derived from various chiral β-amino alcohols that bear substituents with various electron natures at their stereogenic centers are prepared and evaluated for catalyzing the direct Aldol reaction of 4-nitrobenzaldehyde with acetone. Catalysts with strong electron-withdrawing groups are found to exhibit higher catalytic activity and enantioselectivity than their analogues with electron-donating groups. The presence of 2 mol % catalyst 4g significantly catalyzes the direct Aldol reactions of a wide range of aldehydes with acetone and butanone, to give the β-hydroxy ketones with very high enantioselectivities ranging from 96% to >99% ee. High diastereoselectivity of 95/5 was observed for the anti Aldol product from the reaction of cyclohexanone, and excellent enantioselectivity of 93% ee was provided for anti Aldol product from the reaction of cyclopentanone.

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History

  • Published In Issue June 29, 2005
  • Received February 17, 2005

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