화학공학소재연구정보센터
Journal of Catalysis, Vol.193, No.1, 139-144, 2000
Enhanced enantioselectivity in ethyl pyruvate hydrogenation due to competing enantioselective aldol reaction catalyzed by cinchonidine
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.