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New Chiral Phase Transfer Supported Catalysts in The Asymmetric Synthesis of a -Amino Acids : The Importance of a Spacer
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1  Universite de Rouen, UPRES-A 6014 et Institut de Recherche en Chimie Organique Fine (IRCOF), Rue Tesniere 76821 Mont Saint Aignan Cedex, France

Abstract: Polymer-supported cinchona alkaloid salts with different spacers were used as phase transfer catalysts in the asymmetric C-alkylation of N-diphenyl methylene glycine t-butyl ester for the synthesis of phenylalanine. Various catalysts and alkylation conditions were studied, the best result being 81% ee with cinchoninium iodide bound to polystyrene with a four carbon spacer.
Keywords: a -amino acids, polymer-supported catalysts, asymmetric phase transfer catalysis