Synthesis of 5S-(1-Oxoalkyl and Aryl)-2-pyrrolidinone Derivatives1

N-Benzyl pyroglutamate esters react with aryllithium reagents and methyllithium to give moderate to good yields of 5-(1-oxoaryl) or 5-(1-oxoalkyl)-2-pyrrolidinone derivatives. The reaction proceeds without racemization, but is accompanied by formation of 5-(1-hydroxy-1-alkyl)-2-pyrrolidinone derivatives. This reaction gives very poor yields of ketone products with most other alkyl organolithium reagents such as n-butyllithium. Grignard reagents react to give primarily the alcohol.