Reactivity of Phosphorus Centered Radicals

The recent literature devoted to the chemical reactivity of the main families of phosphorus centered radicals is surveyed. Various tin-free radical chain reactions involving L2P-H or L2P(O)-H compounds as hydrogen donors and the corresponding phosphinyl (L2P•) or phosphonyl [L2P(O)•] radicals as chain carriers have been developed. The photo-Arbuzov rearrangement of arylalkylphosphites has been intensively investigated and applied to the preparation of biologically active phosphonates. Single electron transfer reactions involving phosphoniumyl radicals have been applied to the dediazoniation of arenediazonium salts and to the oxidation of trivalent phosphorus compounds. The versatile chemistry of phosphoranyl radicals has been illustrated through various original reactions like the synthesis of phosphonates via free radical Arbuzov reactions and radical chain desulfurizations. New persistent or stable phosphorus centered radicals have been characterized. Different reports have shown that the properties of an organic free radical can be dramatically changed when a phosphorus group is in the vicinity of the radical center.