Enhanced enantioselectivity in ethyl pyruvate hydrogenation due to competing enantioselective aldol reaction catalyzed by cinchonidine

被引：39

作者：

Ferri, D ^{[1
]}

Bürgi, T ^{[1
]}

Borszeky, K ^{[1
]}

Mallat, T ^{[1
]}

Baiker, A ^{[1
]}

机构：

[1] ETH Zentrum, Tech Chem Lab, CH-8092 Zurich, Switzerland

来源：

JOURNAL OF CATALYSIS | 2000年 / 193卷 / 01期

关键词：

enantioselective hydrogenation; Pt/alumina; cinchonidine; ethyl pyruvate; enantioselective aldol reaction;

D O I：

10.1006/jcat.2000.2870

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

LR and NMR experiments revealed that the enantioselective hydrogenation of ethyl pyruvate in nonacidic solvents is complicated by the simultaneously occurring self-condensation (aldol reaction) of the reactant. Both enantioselective reactions are catalyzed by the chiral base cinchona alkaloid, but the hydrogenation is faster by several orders of magnitude than the aldol reaction. Catalytic experiments proved that the aldol products are not spectator species. The enol form of the major aldol product protonates the quinuclidine N of cinchonidine and enhances the enantiomeric excess of the hydrogenation reaction. The significance of this observation with respect to kinetic and mechanistic studies is discussed. (C) 2000 Academic Press.

引用

页码：139 / 144

页数：6