2.14 Selected Diastereoselective Reactions: Enolate Alkylation

This chapter discusses processes in which enolates are subjected to reaction with alkylating reagents. In all the processes examined here, at least one of the two reaction components is chiral and the reaction gives rise to one or more diastereomeric compounds. In most cases, the enolate is generated through deprotonation of the corresponding carbonyl precursor with a suitable base, but in several cases, the enolate is generated differently, for example, through Michael addition of a nucleophile to a conjugated carbonyl compound. The various factors that have been found to influence the stereochemical outcome of the alkylation reaction in a measurable way are also discussed. The material has been organized according to the type of carbonyl precursor used and then categorized with regard to its cyclic or acyclic nature. The pertinent information has been taken from studies published between 1995 and 2010.