Stereoselective Formation of Quaternary Carbon Centers: Alkylation of α,α-Disubstituted Amide Enolates

High diastereoselectivity is achieved in the alkylation of α,α‐disubstituted amide enolates to form quaternary carbon products (see scheme; LiDBB=di‐tert‐butyldiphenyllithium). No chelating groups are necessary for stereocontrol in either the enolate‐formation or alkylation steps. In many cases, amplification of the alkylation diastereoselectivity above the isomeric ratio of the intermediate enolates is observed.