Synthesis of <i>gem</i>-Difluoroalkenes via Zn-Mediated Decarboxylative/Defluorinative Cross-Coupling

Abstract

An efficient and mild Zn-mediated decarboxylative/defluorinative alkylation of α-trifluoromethyl alkenes using <i>N</i>-hydroxyphthalimide esters as radical precursors was developed. Several α-trifluoromethyl alkenes were readily coupled to a wide range of primary, secondary, and tertiary radicals, affording the desired <i>gem</i>-difluoroethylenes in moderate to excellent yields. This reaction protocol was also successfully applied to the construction of complex molecules such as the bioactive natural dehydroabietic acid and glycosyl groups bearing the <i>gem</i>-difluoroethylene moiety.