Highly efficient small organic molecules for enantioselective direct aldol reaction in organic and aqueous media

A series of highly efficient organocatalysts have been derived from naturally available amino acids for carrying out enantioselective direct aldol reaction in both organic and aqueous medium. The aldol products were obtained in high diastereoselectivities (up to 99:1) and enantioselectivities (up to >99% ee) for a broader range of substrates using 1 mol % of a catalyst. The results demonstrate that the structural features of organocatalysts play a crucial role in obtaining high optical purity of aldol adducts in an aqueous medium. Further, the role of water in increasing the rate and enantioselectivity of the reaction has been illustrated. Moreover, the aldol products have been employed in the synthesis of chiral amino alcohols which act as useful intermediates for building up complex natural products.