Metal-Free Divergent Synthesis of Dithiophosphinates and Phosphine Sulfides via Photocatalytic Multicomponent Reactions

A photocatalytic multicomponent reaction has been developed for the synthesis of dithiophosphinates with exclusive anti-Markovnikov selectivity and 100% atom economy, using the easily-available Rhodamine 6G (RhB 6G) as the photocatalyst. This method enables the one-pot construction of S-C-P=S four chemical bonds from easily-available diphenylphosphine, elemental sulfur, and alkenes in THF solvent, and tolerates a variety of alkenes including mono-, di-, and even tri-substituted ones and can be easily scaled up in gram scale, showing excellent practicality. Moreover, the selective synthesis of valuable phosphine sulfides with exclusive anti-Markovnikov selectivity from identical starting materials can also be achieved by controlling the loading of elemental sulfur and conducting under neat (solvent-free) conditions.