Palladium-Catalyzed <i>ipso</i> -Didefluoroannulation of Allylic <i>gem</i> -Difluorides with Salicylic Acids

A palladium-catalyzed C3-<i>ipso</i>-didefluoroannulation of allylic <i>gem</i>-difluorides with salicylic acids has been developed, proceeding under mild conditions with broad functional group tolerance and enabling late-stage functionalization of bioactive scaffolds. Mechanistic studies reveal a key monofluoroalkene intermediate that undergoes two successive Pd(0)/Pd(II) cycles involving C-F activation and allylic C-O oxidative addition with a formal 1,3-ether migration, thereby reversing both catalyst- and nucleophile-controlled regioselectivities. This strategy not only expands the synthetic utility of allylic <i>gem</i>-difluorides but also establishes a new paradigm for regioselective C-F bond functionalization in transition metal catalysis.