Stereoselective synthesis of 2-(S)-(3,5-bis(trifluoromethyl)benzyloxy)-3-(S)-phenyl-1,4-oxazine

A convenient process for the preparation of the secondary amine 6, 2-(S)-(3,5-bis(trifluoromethyl)benzyloxy)-3-(S)-phenyl-1,4-oxazine, is described starting from the readily available (S)-phenylglycine 1. The process features efficient construction of the homochiral oxazinone intermediate 3 and stereoselective introduction of the 2-(3,5-bis(trifluoromethyl)-benzyloxy) group by L-Selectride reduction followed by in situ alkylation with the highly reactive 3,5-bis(trifluoromethyl)-benzyl triflate 4. (C) 1997 Elsevier Science Ltd.