Adduct-catalyzed tandem electro-thermal synthesis of organophosphorus (III) compounds from white phosphorus.

Abstract

Electrooxidation strategies for synthesizing readily oxidizable products face notable challenges, especially when the oxidation potential of the products is lower than that of the reactants or when high current densities are necessary. The electrooxidation synthesis of trivalent organophosphorus compounds (OPCs (III)) from white phosphorus (P₄) has demonstrated potential but is hindered by selectivity issues due to over-oxidation. Herein, we report a tandem electro-thermal synthesis pathway that addresses these challenges in producing OPCs (III) from P₄. The process begins with an electrooxidation step that generates a stable trivalent phosphorus transfer reagent, then thermochemically converted into various high-value OPCs (III). Utilizing hexafluoroisopropanol (HFIP) as the nucleophile and optimizing a tetrabutylammonium iodide (TBAI)-4-dimethylaminopyridine (DMAP)-adduct catalytic system, we developed an efficient electrophilic phosphorus transfer reagent via electrosynthesis. The adduct facilitates the oxidation of P₄ and enhances the nucleophilicity of HFIP, thereby improving the electrooxidation process. This approach supports high current density, scales up to the hundred-gram level without yield loss, and remains compatible with fluctuating green electricity.