Synthesis of Difluoroalkenes from Thiocarbonyl Compounds via Difluorothiiranes: Electrophilic Counterpart to Wittig-Type Difluoromethylidenation

The synthesis of 1,1-difluoro-1-alkenes was achieved by the treatment dithioesters and thioketones with trimethylsilyl 2-fluorosulfonyl-2,2-difluoroacetate in presence a proton sponge catalyst, namely, 1,8-bis(dimethylamino)naphthalene. generated electrophilic difluorocarbene (:CF2) reacted thiocarbonyl functionalities to form 2,2-difluorothiirane intermediates, desulfurization which afforded products Barton–Kellogg-type difluoromethylidenation. reaction described herein is an counterpart Wittig-type (nucleophilic) difluoroalkene starting from carbonyl compounds. difluoromethylidenation facilitated sulfanylated diarylated 1,1-difluoroalkenes, including sterically hindered ones, are inaccessible nucleophilic