A new synthetic route to chiral 3-aryl-5-ethyl-1,4,2-oxazaphosphorines

Diastereoselective synthesis of racemic and enantiopure 3-aryl-5-ethyl-1,4,2-oxazaphosphorines, including those bearing phenolic hydroxyl groups in the exocyclic aromatic fragment, was implemented by the reaction of imines derived from (+/-)- and (R)-(-)-2-aminobutan-1-ol and (hydroxy)benzaldehydes with triethyl phosphite and trifluoroacetic acid, followed by the one-pot dealkylation of the intermediate esters.