The synthesis of 3,3-difluoro-2-oxindoles through a robust and efficient palladium-catalyzed C-H difluoroalkylation is described. This process generates a broad range of difluorooxindoles from readily prepared starting materials. The use of BrettPhos as the ligand was crucial for high efficiency. Preliminary mechanistic studies suggest that oxidative addition is the rate-determining step for this process.
“Palladium-Catalyzed Intramolecular C-H Difluoroalkylation: Synthesis of Substituted 3,3-Difluoro-2-oxindoles”, Angew. Chem. Int. Ed., 2015, 54, 1646-1650.