Redox-neutral conversion of ubiquitous PV sources to a versatile PO2+ phosphorylation reagent

Phosphorus and its compounds are a cornerstone of biological life, as well as finding applications in material science, for example, as flame retardants, battery electrolytes or catalysts. In most applications, phosphorus-containing fine chemicals are in the naturally occurring and most stable oxidation state +V of the element; however, syntheses to these compounds from primary P-V sources rely on an energy-consuming and wasteful redox detour via elemental white phosphorus (P-4) and its subsequent (oxy)chlorination to PCl3, PCl5 and POCl3. Here we report an approach using trifluoromethanesulfonic anhydride (Tf2O) and pyridine to directly cleave P-O bonds in ubiquitous P-V sources to form the versatile PO2+ phosphorylation agent (pyridine)(2)PO2[OTf] (1[OTf]), whose preparation and mechanism of formation is discussed. Harnessing its reactivity towards various nucleophiles such as amines, alcohols and pseudohalogenides, 1[OTf] then provides redox-neutral access to a range of value-added P-V chemicals downstream of low-cost phosphoric acid or other phosphate sources.