Palladium-catalyzed asymmetric (4 + 3) cycloaddition of N-2,2,2-trifluoroethylisatin ketimines: access to optically active spirooxindoles

Abstract

A palladium-catalyzed asymmetric (4 + 3) cycloaddition of N-2,2,2-trifluoroethylisatin ketimines with 2-methylidenetrimethylene carbonate was reported to enantioselectively afford trifluoromethylated spirooxindoles in moderate yields and good to excellent ee values. Experimentally, the reaction proceeded smoothly in the absence of a Brønsted base in a one-pot manner, which paved a way for efficient and cost-effective construction of optically pure trifluoromethylated medium-sized rings.