Stereoselective Fluoro-Deuteration/Chalcogenation/Halogenation of <i>gem</i>-Difluoroallenes (DFAs)

A practical and highly stereoselective approach for the synthesis of α-functionalized trifluoromethylated alkenes has been developed, enabling the incorporation of deuterium, halogen, or chalcogen atoms. The method accommodates a wide range of substrates and delivers the desired products in good yields with excellent <i>E/Z</i> selectivity. The reaction proceeds through a vinyl silver intermediate, formed <i>via</i> AgF addition to <i>gem</i>-difluoroallenes. Control experiments underscore the essential role of the <i>gem</i>-difluoro group in activating the α-carbon to initiate the reaction.