Isothioureas as convenient sulfur donors in P–S bond formation

Isothioureas are demonstrated as practical sulfur donors for mild, one-pot P–S bond formation. Treatment with piperidine releases thiolate, which undergoes aerobic oxidation to the corresponding disulfide. Subsequent cross-dehydrogenative coupling with phosphine oxides affords phosphinothioates, phosphorothioates and phosphonothioates in high yields. The method proceeds under air, tolerates diverse organophosphorus functional groups, and avoids malodorous reagents or external oxidants, providing an efficient and operationally simple route to P–S–containing organophosphorus compounds.