Identification of a key intermediate in the asymmetric Appel process: one pot stereoselective synthesis of P-stereogenic phosphines and phosphine boranes from racemic phosphine oxidesElectronic supplementary information (ESI) available: Full experimental procedure, and full characterization data for phosphine oxides and boranes; HPLC traces of all scalemic phosphine boranes. See DOI: 10.1039/c2cc34136k

Sequential treatment of racemic phosphine oxides with oxalyl chloride and chiral non-racemic alcohol generates the same ratios of diastereomeric alkoxyphosphonium salts obtained in the corresponding asymmetric Appel process, strongly implicating the intermediate chlorophosphonium salt in the stereoselecting step. Subsequent reduction allows a novel synthesis of enantioenriched P -stereogenic phosphines-phosphine boranes. Identification of Appel Intermediates: unprecedented and convenient one pot synthesis of scalemic phosphine and phosphine borane from racemic phosphine oxide.