Small Peptides Catalyze Highly Enantioselective Direct Aldol Reactions of Aldehydes with Hydroxyacetone: Unprecedented Regiocontrol in Aqueous Media

Abstract
L-Proline-based small peptides have been developed as efficient catalysts for the asymmetric direct aldol reactions of hydroxyacetone with aldehydes. Chiral 1,4-diols 7, which are disfavored products in similar aldol reactions catalyzed by either aldolases or l-proline, were obtained in high yields and enantioselectivities of up to 96% ee with peptides 3 and 4 in aqueous media.