Palladium-catalyzed dual dearomatization of indoles and phenols: access to indolinone-fused polycycles.

A palladium-catalyzed intermolecular dual dearomatization reaction that combines indole and phenol substrates in a single operation has been developed. The cascade proceeds through an intramolecular Heck cyclization of the indole moiety to generate a benzylic palladium intermediate, which then coordinates with an alkyne and triggers the dearomatization of the phenol component. This divergent protocol enables rapid assembly of indolinone-fused polycycles bearing contiguous stereocenters as well as spirocyclic frameworks, significantly expanding the structural complexity accessible from simple planar precursors.