Direct and Rapid Synthesis of Arylphosphines (PIII) by Oxalyl Chloride Promoted Reduction of Inorganic Phosphorus Salts [TBA][H2PO4] with Trichlorosilane and Palladium Catalysis

Abstract Given the high demand for organophosphorus compounds (OPCs), developments of sustainable routes toward OPCs synthesis attract much attention. Numerous efforts are contributing to P 4 transformations into P 1 chemistry. Nevertheless, the existing methods necessitate energy-immense multisteps often utilize corrosive and dangerous reagents originating from P 4 /P red allotropes, harmful intermediates, and chemical waste, impeding further exploration and practical applications. Herein, direct and efficient transformation of inorganic phosphates [TBA][H 2 PO 4 ] into OPCs is demonstrated. These salts were activated by cost-efficient oxalyl chloride at 20°C in 5 minutes, through a double chlorination of OH on phosphorus upon elimination of CO 2 and CO molecules, followed by reducing the resultant intermediate with trichlorosilane, then coupling with haloaryls under palladium-catalysis to provide desired OPCs. Diverse OPCs with tolerance of various functionalities on aryl halides achieved with potential scale-up and industrial applications, eliminating the reliance on extortionate, problematic P 4 allotropes. X-ray diffraction and DFT calculations revealed activated intermediate [TBA][PO 2 Cl 2 ].