Efficient interconversion of α,α-difluoromethylenephosphonates and α,α-difluoromethylenephosphonothioates

Article abstract of DOI:10.1016/0040-4039(96)00912-4

Treatment of dialkyl 1,1-difluoromethylenephosphonates 1 with Lawesson's reagent cleanly produces the corresponding dialkyl 1,1-difluoromethylenephosphonothioates 2. The reaction can be extended to dialkyl 1,1-difluoromethylenephosphinates and to dialkyl 1,1-difluoromethylenephosphine oxides. The reversed transformation (i.e. converting dialkyl 1,1-difluoromethylenephosphodioxirane 7 or perfluoro-cis-2-n-butyl-3-n-propyloxaziridine 8, and produces the desired phosphonates in high yield. The synthetic interest of these transformations is discussed.