Pd-Catalyzed Spirocyclization via C-H Activation and Benzyne Insertion.

A palladium-catalyzed spirocyclization forming spirooxindoles and spirodihydrobenzofurans has been achieved. Mechanistic studies suggest that the transformation proceeds through sequential carbopalladation, C-H activation, and benzyne insertion. Both classes of spirocycles have been synthesized in good to excellent yields, and the procedure is readily scalable.