Cinchonium Betaines as Efficient Catalysts for Asymmetric Proton Transfer Catalysis: The Development of a Practical Enantioselective Isomerization of Trifluoromethyl Imines

We have developed a new class of cinchonium betaine catalysts bearing both a base moiety and an aromatic moiety as an N-substituent of the quinuclidine motif. These cinchonium betaines were found to promote proton transfer catalysis with 1000-5000 turnovers per 24 h, thereby enabling us to realize highly efficient enantioselective isomerization of trifluoromethyl imines to provide a practical access to optically active trifluoromethylated amines.