Chiral, non-racemic α-hydroxyphosphonates and phosphonic acids via stereoselective hydroxylation of diallyl benzylphosphonates

Chiral, non-racemic alpha-hydroxyphosphonates have been prepared in high enantiomeric excess (96-98% ee), via stereoselective oxaziridine-mediated hydroxylation of diallyl benzylphosphonates. The enantiomeric purity and absolute configuration of the alpha-hydroxyphosphonates was established from H-1 and P-31 NMR spectroscopy of the (S)-O-methylmandelate esters. Deprotection of the diallyl alpha-hydroxyphosphonates under neutral conditions furnished the corresponding free phosphonic acids, retaining a high degree of stereochemical purity (90 to >98% ee). (C) 2003 Elsevier Science Ltd. All rights reserved.