Study of the asymmetric synthesis of (Z)-gamma-substituted alpha,beta-didehydroglutamates from N-alkylideneglycinates

The synthesis of (Z)-gamma-substituted-alpha,beta-didehydroglutamates has b een accomplished either starting from the glycinates 1 or the alpha,beta-di dehydroglutamates 6. In the first case, no reaction of the lithium enolates 3 was observed, and the use of the naked anions 4 was required; while in t he second case, the Lithium enolates 7 reacted successfully with alkyl hali des to afford the target molecules. (C) 1999 Elsevier Science Ltd. All righ ts reserved.