Chiral N,N′-Dioxide-Zinc(II) Complex-Catalyzed Asymmetric Aza-Friedel-Crafts Reaction of Isatin-Derived Ketimines with Indoles

A highly efficient chiral N,N'-dioxidezinc(II) complex catalytic system has been developed for the enantioselective aza-Friedel-Crafts reaction of isatin-derived ketimines with indoles. A series of enantiomerically enriched 3-indolyl-3-ami-nooxindoles containing a tetrasubstituted stereocenter were obtained in up to 99% yield with up to 96% ee. Furthermore, control experiments provide a fundamental sight into the mechanism of the reaction.