First Michael Addition Reaction of α-Substituted N-Diphenylmethyleneglycinate with Ethyl Propiolate. Synthesis of α-Substituted (E)-3,4-Dehydroglutamic Acids

Abstract

(E)-α-substituted 3,4-dehydro glutamic acids 4, were prepared from ethyl N-diphenylmethyleneglycinate 5 by alkylation with a suitable alkyl halide followed by a Michael type addition reaction with ethyl propiolate, giving rise to a mixture of EZ adducts 78. Sequential hydrolysis of the substituted glycine synthons 78 afforded the titled compounds 4 as single diastereomers.