Ammonium Hydroxide → tert-butyl (2S,3R)-4-amino-3-hydroxy-1-phenylbutan-2-ylcarbamate

Participants

Reaction Steps

A solution of tert-butyl (S)-1-((S)-oxiran-2-yl)-2-phenylethylcarbamate (1.5 g, 5.7 mmol) in EtOH (35 mL) was added, with stirring, over 1 h to NH4OH (35 mL) at 0° C. NH3 gas was bubbled through the reaction mixture during the addition and for 1 h afterward. The reaction mixture was allowed to warm to room temperature and stirred overnight. The resulting slurry was diluted with EtOAc (80 mL), and the organic layer was washed with brine and dried (MgSO4). Concentration in vacuo, followed by trituration with 10% i-PrOH-EtOAc (overnight stirring), afforded tert-butyl (2S,3R)-4-amino-3-hydroxy-1-phenylbutan-2-ylcarbamate (0.44 g) as a white solid. The mother liquors were concentrated in vacuo and triturated again as above to give an additional quantity of tert-butyl (2S,3R)-4-amino-3-hydroxy-1-phenylbutan-2-ylcarbamate (0.57 g; 64% total yield): 1H NMR (CD3OD) d: 1.29 (s, 9H), 2.55 (m, 1H), 2.63 (m, 1H), 2.76 (m, 1H), 3.11 (m, 1H), 3.40 (m, 1H), 3.65 (m, 1H), 7.10-7.30 (m, 5H).

Provenance & Evidence