General and chemoselective reduction of phosphine oxides by an enhanced oxophilic competition mechanism†

Abstract

Chemoselective reduction of phosphine oxides holds great significance for the preparation of phosphorus ligands and catalysts, as well as for the sustainable development of phosphorus chemistry. Previous approaches in this regard primarily involved the use of metal or custom-built catalysts, highly reactive and expensive reagents, or harsh conditions with deficient chemoselectivity. Here, we report an organocatalysis strategy for facile and efficient PO reduction, utilizing only commercially available catalysts and inexpensive, mild silanes under mild reaction conditions. This approach demonstrates excellent chemoselectivity for preserving various easily reduced groups. Computational studies elucidate that the enhanced oxophilicity of catalytically generated electron-deficient silane species is crucial. Furthermore, scale-up investigations highlight potential applications in industrial recycling of phosphine oxides and straightforward preparation of novel phosphorus ligands.