A trimeric Cinchona alkaloid ammonium salt, alpha,alpha',alpha" -tris[O(9)-allylcinchonidinium]mesitylene tribromide has been prepared as a novel phase-transfer catalyst. The catalytic enantioselective alkylation of N-(diphenylmethylene)glycine tert-butyl ester using the trimer catalyst showed high enantioselectivity (90-97% ee). (C) 2001 Elsevier Science Ltd. All rights reserved.