Sodium triacetoxyborohydride → methyl 3-(((2R,3S)-3-(tert-butoxycarbonylamino)-2-hydroxy-4-phenylbutylamino)methyl)-5-methoxybenzoate

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Reaction Steps

A solution of tert-butyl (2S,3R)-4-amino-3-hydroxy-1-phenylbutan-2-ylcarbamate (300 mg, 1.07 mmol) in THF was added methyl 3-formyl-5-methoxybenzoate (294 mg, ˜80% purity, 1.07 mmol) and stirred for 30 min at room temperature, NaB(OAc)3H (453.7 mg, 2.14 mmol) was then added portionwise in 30 min, finally 5 drops of acetic acid was added and the resulting mixture was stirred at the same temperature overnight. The reaction mixture was diluted with EtOAc, and washed with saturated aqueous NaHCO3. The organic layer was separated and dried (MgSO4). Concentration in vacuo, followed purification with flash chromatography to give the desired product methyl 3-(((2R,3S)-3-(tert-butoxycarbonylamino)-2-hydroxy-4-phenylbutylamino)methyl)-5-methoxybenzoate as a white solid (390 mg, % yield). 1H NMR (CDCl3): d: 8.583 (s, 1H), 7.447 (s, 1H), 7.298-7.166 (m, 5H), 7.092 (s, 1H), 3.899 (s, 3H), 3.832 (s, 4H), 3.779 (s, 2H), 3.572 (m, 1H), 2.2.946 (m, 1H), 2.777 (m, 1H), 2.711 (m, 2H), 1.330 (s, 9H).

Provenance & Evidence