Rhodium-Catalyzed Reductive Aldol Reactions Using Aldehydes as the Stoichiometric Reductants

Abstract
Chelated acyl rhodium hydrides, generated from the addition of [Rh(dppe)]ClO4 to β-sulfide-substituted aldehydes, can function as the stoichiometric reductants in reductive aldol processes. Unsaturated nitriles, esters, and ketones can be used as enolate equivalents, and a variety of simple α- and β-substituted aldehydes can be employed. The use of a second, more electrophilic, aldehyde allows three-component reactions to be performed.