使用双功能脲提高脯氨酸催化的α-氨氧基化反应速率。

Use of bifunctional ureas to increase the rate of proline-catalyzed alpha-aminoxylations.

作者信息

Poe Sarah L, Bogdan Andrew R, Mason Brian P, Steinbacher Jeremy L, Opalka Suzanne M, McQuade D Tyler

机构信息

Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.

出版信息

J Org Chem. 2009 Feb 20;74(4):1574-80. doi: 10.1021/jo802461w.

DOI:10.1021/jo802461w

PMID:19199658

Abstract

The rate of the proline-catalyzed alpha-aminoxylation of aldehydes is significantly increased in the presence of a bifunctional urea. Structure-activity relationship data indicate that both an amine and a urea are crucial for rate enhancement. The evidence presented herein suggests that this rate enhancement originates from the hydrogen bonding interaction between the bifunctional urea and an oxazolidinone intermediate to increase the rate of enamine formation. Proline derivatives that are incapable of forming oxazolidinones exhibit no rate enhancement in the presence of the bifunctional urea. The rate enhancement is general for a variety of aldehydes, and the faster reactions do not reduce yields or selectivities.

摘要

在双功能脲存在的情况下，脯氨酸催化的醛的α-氨基氧基化反应速率显著提高。构效关系数据表明，胺和脲对于速率提高都至关重要。本文提供的证据表明，这种速率提高源于双功能脲与恶唑烷酮中间体之间的氢键相互作用，以提高烯胺形成的速率。不能形成恶唑烷酮的脯氨酸衍生物在双功能脲存在下没有速率提高。对于多种醛来说，速率提高是普遍现象，且更快的反应不会降低产率或选择性。