Cinchona alkaloid-derived quaternary ammonium salt combined with NaH: a facile catalyst system for the asymmetric trifluoromethylation of ketones

Enantioselective trifluoromethylation of aromatic ketones promoted by the cinchona alkaloid-derived ammonium bromide and sodium hydride was described. A series of trifluoromethyl-substituted aryl alcohols could be obtained in Lip to 82% ee with 98% yield under mild conditions. A possible catalytic cycle was also presented. (C) 2009 Elsevier Ltd. All rights reserved.