Asymmetric Alkylation of Oxindoles Catalyzed by 1,2,3-Triazolium Salts

Significance

Chiral 1,2,3-triazolium salts (e.g., 1˙Br) were developed as a novel class of phase-transfer catalysts and applied to the asymmetric alkylation of 3-substituted oxindoles 2. Oxindoles 4 with quaternary carbon stereocenters were obtained in high yields and with high to excellent enantioselectivity. An attractive feature of this novel catalyst class is their synthesis, which readily enables structural modifications.