Chiral Bronsted-Acid-Catalyzed Enantioselective Arylation of Ethyl Trifluoroacetoacetate and Ethyl Trifluoropyruvate

Chiral phosphoric acid was found to be an effective organocatalysts for the direct enantioselective arylation of ethyl 4,4,4-trifluoroacetoacetate (ETFAA). A series of chiral trifluoromethyl-substituted tertiary alcohols were obtained in moderate to high yields with up to 78% ee. Several desired products were obtained with excellent optical purities after a single re crystallization. This method was also extended to ethyl trifluoropyruvate, which is complementary to systems catalyzed by Lewis acids and cinchona alkaloids. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)