112741-49-8

112741-70-5

112741-49-8

N-Boc-substituted diphenylamino alcohol (1.9 g, 4.2 mmol) was dissolved in toluene (25 mL), p-TsOH (p-TsOH, 70 mg, 0.42 mmol) was added, and the reaction was heated and refluxed at 120 °C overnight. Upon completion of the reaction, it was cooled to room temperature and a solid was precipitated. The solid was collected by filtration, washed with saturated aqueous sodium chloride solution, the organic phase was separated, dried over anhydrous sodium sulfate, filtered and concentrated. The yellow solid obtained was recrystallized by anhydrous ethanol (20 mL) to give a white solid. After filtration and drying by rotary evaporation, 1.22 g (2R,3S)-N-tert-butoxycarbonyl-2,3-diphenylmorpholin-6-one was obtained as a white solid in 85% yield.