Synthesis of polytertiary phosphines and ‘mixed’ phosphorus–sulphur and ‘mixed’ phosphorus–nitrogen polydentate ligands via free-radical catalysis

Abstract

In the presence of free radicals, phosphorus–hydrogen and sulphur–hydrogen bonds cleanly and readily add to the carbon–carbon double bonds of vinyl derivatives to produce organic compounds that are useful as polydentate chelating ligands. The generality and mild conditions of the reaction are demonstrated by the synthesis of di-, tri-, and tetra-(tertiary phosphines) and of compounds that contain both phosphorus and sulphur or phosphorus and nitrogen donor groups. This free-radical-catalysed addition of molecules containing P–H and S–H bonds to vinyl compounds provides a general valuable alternative to the base-catalysed addition method.