alpha-Alkylation of N-tosyl-protected beta-amino esters with LDA as the base led to high anti selectivity for the newly formed C-C bond. The alpha-alkylated beta-amino esters were further transformed to enantiomerically pure 4,5-disubstituted pyrrolidinones through hydrolysis, diazotization, and Wolf rearrangement under AgO2CPh/Et3N/dry THF conditions. (C) 1999 Elsevier Science Ltd. All rights reserved.