To elucidate the asymmetric inductive effect of the N-stereogenic centre in quaternary ammonium salts, four quaternary ammonium salts with C-chiral centre were synthesized from amino acids. These salts together with four previously synthesized salts containing both N- and C-chiral centres, were applied as asymmetric phase-transfer catalysts in the enantioselective alkylation of N-(diphenylmethylene)-glycine tert-butyl ester with benzyl bromide. The relationship be-tween the ee values of products and the structures of catalysts indicated that the N-stereogenic centre alone showed no significant effect on the enantioselectivity of alkylation.

Key words: N-stereogenic quaternary ammonium salt, asymmetric catalysis, amino acid, alkylation