Chiral N,N′-Dioxide/Scandium(III)-Catalyzed Asymmetric Alkylation of N-Unprotected 3-Substituted Oxindoles
An efficient enantioselective alkylation of N-unprotected 3-substituted oxindoles was realized by using a chiral N,N′-dioxide/scandium(III) complex as the catalyst. A wide range of 3,3-dialkyl substituted oxindoles with quaternary stereocenters were obtained in high yields and ee values (up to 98% yield and 99% ee). (Figure presented.).