A new synthetic method for the enantioselective preparation of a-amino acid derivatives is presented. The key step involves the diastereoselective alkylation of the new chiral glycine enolate synthons 7 and 8 providing alkylation adducts with de of 297.6% in good yields (7340%). The reactivities of the enolates of 7 and 8 were extraordinarily sensitive to the metal counterion and solvent. Experimental conditions are described to maintain high ...