Sulfanyl- and selanyldifluoromethylphosphonates as a source of phosphonodifluoromethyl radicals and their addition onto alkenes

[GRAPHICS] Two different strategies are shown to produce sulfanyl and selanyldifluorom ethylphosphonates, Thus, treatment of sulfanyldichloromethylphosphonates by 3HF . NEt3 in the presence of zinc bromide produces the corresponding sulf anyldifluoromethylphosphonates. In addition, lithiation of difluoromethylph osphonates followed by quenching with phenylsulfanyl chloride, phenylselany l chloride, or diphenyl diselenide yields the corresponding sulfanyl- and s elanyldifluorophosphonates. Generation of phosphonodifluoromethyl radicals from such precursors in the presence of alkenes produces the expected adduc ts.