ASYMMETRIC SYNTHESIS OF (S)-GLUTAMIC ACID VIA NI$^2$ ACHIRAL COMPLEX OF DEHYDROALANINE CATALYZED BY CHIRAL DERIVATIVES OF BINOL

Abstract

An efficient method of catalytic asymmetric synthesis of (S)-glutamic acid was elaborated. The synthesis was carried out via addition of diethyl ester of malonic acid to C=C bond of a achiral Ni^II complex derived from the Schiff base of dehydroalanine and achiral auxiliary reagent (2-benzoylphenyl)amidopyridyl-2-carboxylic acid. The dependency of enantioselectivity of asymmetric reactions from the nature and quantity of catalysts, solvents and bases, as well as from the temperature has been examined. It was shown that in the presence of 10 mol% of 3,3'-bis(diphenylhydroxymethyl)-1,1'-binaphthalenyl-2,2'-diol or its tetrapotassium derivative the stereoselectivity of the reaction reaches 76–80%, and the enantiomeric excess of obtained (S)-glutamic acid exceeds 80%.