Divergent Synthesis of 3,3-Disubstituted Oxindoles Initiated by Palladium-Catalyzed Intramolecular Arylation of Unsaturated Amides

3,3-Disubstituted oxindole derivatives are privileged five-membered heterocycles widely presented in a variety of natural products and pharmaceuticals with significant biological activities. In this paper, diverse boron-substituted oxindoles have been successfully synthesized by Pd-catalyzed intramolecular arylation and borylation cascade of unsaturated amides. More importantly, simply switching the reaction solvents led to other reductive Heck products with the same catalyst and reactants. Control experiments showed that the reductive Heck products were transformed from 3,3-disubstituted oxindole boronic esters in the presence of base.