Selective C–F Bond Allylation of Trifluoromethylalkenes

Selective C−F bond functionalization of CF₃ group represents an appealing strategy for the incorporation of pharmaceutically privileged difluoromethylene moiety. Despite the recent significant advancement attained in the functionalization of Ar-CF₃ molecules, prescriptions amenable for alkenyl-CF₃ congeners remain sufficiently inadequate. Herein, we report a strategically novel protocol for the C−F bond elaboration of trifluoromethylalkene derivatives. By using readily available allyl metallics as nucleophilic coupling partner, the present reaction enables an expedient construction of structurally diversified CF₂-bridged 1,5-dienes. Furthermore, the exquisite selectivity observed in this transformation is revealed to be based on the underlying mechanism that consists of a cascade of nucleophilic S_N2′ defluorinative allylation and electronically promoted Cope rearrangement.