Novel N-acetophenone cinchona ammonium salts have been successfully synthesized and used as chiral phase transfer catalysts for the asymmetric alkylation of tert-butyl benzophenone Schiff base derivatives in aqueous media at room temperature with the highest ee and yield up to 96 and 98%, respectively. We have also studied the influence of substituted acetopheno groups in quaternary ammonium salts derived from the cinchona alkaloids. (c) 2007 Elsevier B.V. All rights reserved.