4-Nitrophenyl chloroformate → (S)-4-nitrophenyl 2-(t-butoxycarbonylamino)-3-cyclohexylpropylcarbamate

Participants

Reaction Steps

To a stirred solution of (S)-tert-butyl 1-amino-3-cyclohexylpropan-2-ylcarbamate (0.65 g, 2.54 mmol) in MeCN (20 mL) and THF (5 mL) was added powdered NaHCO3 (0.43 g, 5.08 mmol) followed by a solution of p-nitrophenyl chloroformate (0.51 g, 5.08 mmol) in MeCN (20 mL) dropwise over 10 min. The mixture was stirred at rt for 2 h, filtered through a pad of Celite and concentrated to leave a white solid. This material was purified by chromatography on a 40-g silica cartridge eluted with a gradient from 0-100% EtOAc in hexanes to afford (S)-tert-butyl 1-(p-nitrophenoxycarbonylamino)-3-cyclohexylpropan-2-ylcarbamate (0.67 g, 67%) as an off-white solid.

Provenance & Evidence