화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.131, No.31, 10842-10842, 2009
Catalytic Asymmetric Synthesis of alpha-Alkylidene-beta-hydroxy Esters via Dynamic Kinetic Asymmetric Transformation Involving Ba-Catalyzed Direct Aldol Reaction
A Ba-catalyzed dynamic kinetic asymmetric transformation (DYKAT) involving a direct aldol/retro-aldol reaction of beta,gamma-unsaturated ester donors is described. A Ba(O-iPr)(2)/BINOL complex promoted the direct aldol reaction/isomerization sequence, and alpha-alkylidene-beta-hydroxy esters were obtained from aryl, heteroaryl, alkenyl, and alkyl aldehydes under simple proton-transfer conditions with 99-87% ee and > 20:1 to 15:1 alpha/gamma selectivity.