Constrained β-Proline Analogues in Organocatalytic Aldol Reactions: The Influence of Acid Geometry

被引：43

作者：

Armstrong, Alan ^{[1
]}

Bhonoah, Yunas ^{[1
]}

White, Andrew J. P. ^{[1
]}

机构：

[1] Univ London Imperial Coll Sci Technol & Med, Dept Chem, London SW7 2AZ, England

来源：

JOURNAL OF ORGANIC CHEMISTRY | 2009年 / 74卷 / 14期

基金：

英国工程与自然科学研究理事会;

关键词：

POLARIZABLE CONTINUUM MODEL; SAUER-WIECHERT REACTION; MANNICH-TYPE REACTIONS; ASYMMETRIC ORGANOCATALYSIS; TRANSITION-STATES; AMINO ACIDS; DENSITY; CATALYSIS; MECHANISM; ALDEHYDES;

D O I：

10.1021/jo900840v

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

7-Azabicyclo[2.2.1]heptane-2-carboxylic acid 11 was prepared in enantiopure form, and its catalytic potential in the direct aldol reaction between acetone and 4-nitrobenzaldehyde was assessed. The bicyclic system was found to be more selective than its monocyclic analogue beta-proline 5b. A comparative density functional theory study of proline 1, beta-proline 5b, and 11 in the latter reaction revealed the origin of the improved enantioselectivity of 11 over 5b. The geometry of the carboxylic acid group in the transition states, which depended critically on pyrrolidine ring conformation, was found to play a key role.

引用

页码：5041 / 5048

页数：8

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