Asymmetric catalysis of aldol reactions with chiral lewis bases.

In an extension of studies both on the stereochemical course of the aldol addition and on Lewis-base-catalyzed allylation reactions, we have invented a new Lewis-base-catalyzed asymmetric aldol addition. This Account outlines the conceptual development, the identification of design criteria, and the underlying principles for such a process. The reduction of these elements to practice in the demonstration of enantioselective aldol additions of trichlorosilyl enolates catalyzed by chiral phosphoramides is also presented. From a combination of stereochemical, kinetic, and structural studies, an intruiging mechanistic hypothesis is forwarded that explains the origin of catalysis and diastereoselectivity.