Study On The L-proline Promoted Copper-Catalyzed Synthesis Of Phosphinothioates And Phosphorothioates

Phosphinothioates,sulfur-containing organophosphorus compounds,are increasingly widely used in organic synthesis,pharmacochemistry and agrochemistry.The coupling reactions between P(O)-H compounds and sulfonyl chlorides are effective methods for the construction of the P-S-C bonds.In this paper,we described L-proline promoted Cu-catalyzed coupling reaction of P(O)-H with sulfonyl chlorides to synthesise phosphinothioates and phosphorothioates.A considerably improved method for the Cu-catalyzed coupling of aryl/alkyl sulfuryl chlorides with P(O)-H was described.Using commercially available L-proline as the ligand decreased the precatalyst loading,broadened the substrate scope and greatly promoted the efficiency of the coupling reaction.A series of sulfonyl chlorides readily couplied with P(O)-H compounds,such as DOPO,H-phosphonates,under the mild reaction condition to produce the corresponding phosphinothioates and phosphorothioates.Moreover,gram-scale preparation and recyclable catalyst featured this transformation.And the easy-to handle Pro/Cu catalyst was able to be reused in multiple consecutive catalytic runs(up to 10 runs)without loss of high reactivity.In addition,the sulfonyl radical in the reaction mixture was successfully captured by free radical capture experiments.Further mechanistic studies were performed via controlled experiments and HRMS tracking experiments to shed light on the mechanism.A plausible Pro/Cu catalyzed free-radical reaction mechanism was proposed on the bases of the results of the experiments and the literature precedents.