REACTION OF SCHIFF BASES ANIONS WITH 4-HALO-2-BUTENOATES : SELECTIVE SYNTHESIS OF α-CYCLOPROPYL AND γ,δ UNSATURATED α-AMINO ACID DERIVATIVES.

Article abstract of DOI:10.1016/S0040-4039(00)84345-2

Depending on the reaction conditions, anions of imines derived from α-aminoesters react with 4-bromo-2-butenoates to give either cyclopropyl derivatives by an addition-elimination or γ,δ-unsaturated iminoesters by a nucleophilic substitution.