Unexpected beneficial effect of ortho -substituents on the (s)-proline-catalyzed asymmetric aldol reaction of acetone with aromatic aldehydes

Abstract

An intriguing effect of electronegative 2,6-substituents on the stereochemical outcome of (S)-proline-catalyzed aldol reactions between benzaldehyde derivatives and acetone is reported. Remarkably high enantioselectivities can be achieved with such substrates. © Georg Thieme Verlag Stuttgart New York.