Discovery and Enantioselective Synthesis of Tetra-Substituted Methylene Oxindole Atropisomers by Palladium-Catalyzed Domino Cyclization

The discovery of atropisomers with unique skeletal structures is important for the development of chiral catalysts, ligands, drugs, and materials. Herein, we report the development of palladium-catalyzed enantioselective domino cyclization chemistry for generating tetra-substituted methylene oxindole atropisomers. A set of rarely reported oxindole-indole atropisomers was synthesized in high yields, with (Z)-stereoselectivities and good enantioselectivities under mild reaction conditions. Importantly, the formed oxindole-indole atropisomer motif could be transferred between Z- and E-alkenes that interconverts four different isomeric states in a fixed sequence upon light irradiation.