Full Paper
Proline Catalyzed Asymmetric Aldol Reaction between Methyl Ketones and α-Ketoesters†
Abstract
Direct asymmetric aldol additions of acetone/and butanone to α-ketoesters were achieved using L-proline as a chiral catalyst. Various optically active α-hydroxyesters were obtained in the yields of 43%–93% with enantioselectivities up to 81% e.e. The steric effect seems to be an important factor which influences the activity and the selectivity of the reaction. Acetone showed higher reactivity than butanone while the latter provided better enantioselectivity in some cases.
