Catalyst-Controlled Chemoselective and Enantioselective Reactions of Tryptophols with Isatin-Derived Imines

Catalyst-controlled chemoselective and enantioselective reactions of tryptophols with isatin-derived imines were demonstrated. Under catalysis with a chiral phosphoric acid, diastereoselective and enantioselective dearomative cyclization occurred, while, in the presence of a chiral squaramide-tertiary amine, enantioselective addition occurred. Both reactions afforded 3-substituted 3-amino-oxindoles in generally good yields (up to 99%) and excellent stereoselectivities (up to >95:5 dr, 99:1 er).