Asymmetric aldol reactions

Abstract The addition of an enolate to a ketone or aldehyde, often :referred to as an aldol reaction, bas a long pedigree, having been studied for many years from both the synthetic and mechanistic points of view. Throughout this volume, the term ‘aldol reaction’ will be used to denote the formation of a β-bydroxycarbonyl system S.2, thereby distinguishing it from an ‘aldol condensation’ which refers to the formation of an α, β-unsaturated carbonyl compound S.3 by P-elimination of an intermediate β-hydroxycarbonyl system. These relationships and definitions are illustrated in Fig. 5.1.