Simple unprecedented conversion of phosphine oxides and sulfides to phosphine boranes using sodium borohydrideElectronic supplementary information (ESI) available: Full experimental procedure, and full characterization data for phosphine oxides, sulfides and boranes; 31P NMR data for all CPS; NMR spectra and HPLC traces of phosphine boranes. See DOI: 10.1039/c1cc14856g

A variety of phosphine oxides and sulfides can be efficiently converted directly to the corresponding phosphine boranes using oxalyl chloride followed by sodium borohydride. Optically active P -stereogenic phosphine oxides can be converted stereospecifically to phosphine boranes with inversion of configuration by treatment with Meerwein's salt followed by sodium borohydride. We describe a method to replace O or S with BH 3 , achirally or stereospecifically, under mild conditions.