Modular Synthesis of Diverse <i>gem</i> -Difluoroalkenes from Trifluoroacetic Anhydride via Phosphorus-Assisted Fluoride Elimination

Here we report a modular strategy for constructing structurally diverse <i>gem</i>-difluoroalkenes via phosphorus-assisted fluoride elimination using trifluoroacetic anhydride as the fluorine source. The protocol provides access to fully substituted architectures with unprecedented generality across alkyl, aryl, alkenyl, alkynyl, heteroatom-centered, and fused-ring groups and bioactive heterocycles (indoles, pyrimidines, glycosides), enabling downstream transformations via cycloadditions and functionalization. Mechanistic studies reveal a radical phosphorus-installation step followed by rate-determining P-F elimination.