106973-37-9

101376-26-5

General procedure for the synthesis of (R)-(4-benzyl-3-morpholine)-methanol from (S)-4-benzyl-5-oxo-3-morpholinecarboxylic acid: to a solution of intermediate 66 ((S)-4-benzyl-5-oxo-3-morpholinecarboxylic acid, 12.6 g, 53.6 mmol) in tetrahydrofuran (200 mL) was slowly added the borane-tetrahydrofuran complex (1.0 M. 348mL). The reaction mixture was stirred at room temperature for 6 hours before the reaction was quenched by the addition of methanol, followed by heating to 80 °C and continued stirring for 2 hours. Upon completion of the reaction, the mixture was extracted by adding saturated aqueous sodium bicarbonate and ethyl acetate to the mixture. The aqueous layer was extracted again with ethyl acetate and the organic layers were combined. The organic layer was washed sequentially with water and brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure to remove the solvent. The resulting crude product was purified by silica gel column chromatography (eluent: hexane/ethyl acetate = 90/10 to 10/90 gradient elution) to afford the target product (R)-(4-benzyl-3-morpholine)-methanol (9.60 g, 46.0 mmol, 86% yield). Mass spectrometry (ESI+) showed the molecular ion peak m/z 208 ([M+H]+, 100%).