Synthesis and spectral properties of α,α-difluorinated β-iminophosphonates

A method for the first synthesis of α,α-difluorinated β-iminophosphonates has been developed. The desired 1,1-difluoromethylene-β-iminophosphonates 14a-14d have been obtained by fluorination using Selectfluor® of appropriate β-enaminophosphonates 17a-17d, prepared from β-ketophosphonate 15 precursor. The product structures and geometry of β-enamine/imine double bonds have been determined by 1H NMR, 13C NMR, 19F NMR and 31P NMR.