Water-Controlled Geminal Hydroxyphosphinoylation and Diphosphinoylation of Enaminones with H-Phosphine Oxides

A water-controlled geminal phosphinoylation of enaminones with H-phosphine oxides has been established through AlCl3-mediated C-N bond cleavage in this work, which provides a novel strategy for accessing various hydroxy and diphosphinoyl products 3a and 4a in high yields. The transformation features excellent functional group tolerance, operational simplicity, and high atom economy, and is amenable for phosphinoylation of complex molecule skeletons. Preliminary mechanism studies suggest the conversion from 3a to 4a involve the elimination of hydroxyl group, and water and temperature plays a critical role in influencing the reaction pathway and product selectivity. This research provides significant value to the geminal functionalization of enaminones.