Fluoro-Wacker Gem -Difluorination of Alkene via Fluoropalladation and Dyotropic Rearrangement

Nucleopalladation of alkenes is a fundamental elementary step in palladium catalysis and underpins a wide range of alkene functionalization reactions. However, fluoropalladation using readily accessible and synthetically practical fluoride sources remains markedly underdeveloped. We report herein a palladium-catalyzed migrative 1,1-difluorination of 1,1-disubstituted alkenes that proceeds through nucleophilic fluoropalladation, oxidation of the resulting alkyl-Pd(II) intermediate to Pd(IV), and a subsequent 1,2-Csp3/Pd(IV) dyotropic rearrangement. The triethylamine tris(hydrogen fluoride) complex (Et3N·3HF) serves as an efficient nucleophilic fluoride source and is fully compatible with Selectfluor, which oxidizes Pd(II) to Pd(IV) and triggers migratory rearrangement. This work establishes fluoropalladation-initiated Pd(IV) dyotropic rearrangement as a viable mechanistic platform for migrative alkene difunctionalization and enables efficient conversion of 1,1-disubstituted alkenes into ring-expanded or chain-extended products bearing a gem-difluoromethylene unit.