N-Tosyl-(Sa)-binam-L-prolinamide as highly efficient bifunctional organocatalyst for the general enantioselective solvent-free aldol reaction

Abstract

N-Tosyl-(Sa)-binam-L-prolinamide (5 mol%) and benzoic acid (1 mol%) were used as catalysts in the enantioselective direct aldol reaction between different ketones and aldehydes under solvent-free conditions in the presence or absence of water. Under this reaction conditions it was possible to reduce the amount of required ketone to 2 equiv to give the corresponding aldol products with high yields, regio-, diastereo- and enantioselectivities. The aldol reaction between aldehydes or the intramolecular aldol reaction can be also performed with excellent results.