Platinum-Catalyzed C3 - Ipso Deep C–F Editing of Allylic Gem -Difluorides via Base-Switchable Divergent Annulation

Allylic gem-difluorides are readily accessible fluorinated building blocks, yet their Pt-catalyzed allylic functionalization remains limited in nucleophile scope and is typically dominated by terminal monodefluorofunctionalization. Herein, we report a Pt(0)-catalyzed C3-ipso didefluoroannulation of allylic gem-difluorides with o-indolyl phenols, enabling formal replacement of two C–F bonds and rapid access to diverse indole-fused O-heterocycles. The reaction manifold is controlled by basicity: base-free conditions favor C, O-annulation through indole C3 capture, whereas NaH promotes N, O-annulation through indole N participation from the same substrate platform. Mechanistic studies support a phenoxy O-initiated pathway involving Pt-mediated allylic C–F activation, formation of a monofluorinated allyl ether, and α-fluoride elimination to a common oxonium/oxocarbenium intermediate. This work expands Pt-mediated C–F functionalization and establishes an ipso-selective strategy for deep C–F editing of allylic gem-difluorides.