Dimethyl Sulfoxide → tert-butyl (1R,4S)-4-((S)-3-benzyloxycarbonylamino-2-oxopyrrolidin-1-yl)-3-formylcyclohexylcarbamate

Participants

Reaction Conditions

Reaction Steps

A solution of oxalyl chloride (2.0 M in dichloromethane, 370 μL, 735 μmol) in dichloromethane (1.6 mL) was stirred at −78° C. Dimethyl sulfoxide (108 μL, 1.51 mmol) was added dropwise over about 2 min, and the mixture was stirred for 35 min. A solution of tert-butyl (1R,3R,4S)-4-((S)-3-benzyloxycarbonylamino-2-oxopyrrolidin-1-yl)-3-(hydroxymethyl)cyclohexylcarbamate (219 mg, 475 μmol, See Example 4a, Step 1) in dichloromethane (1.5 mL) was added and the solution was stirred at −78° C. for 65 min. Triethylamine (215 μL, 1.54 mmol) was added, and after 10 min the mixture was warmed to 0° C. and stirred for 2 h. The mixture was diluted with dichloromethane, washed with saturated aqueous ammonium chloride, then with water, and was dried over sodium sulfate and concentrated under vacuum to provide tert-butyl (1R,4S)-4-((S)-3-benzyloxycarbonylamino-2-oxopyrrolidin-1-yl)-3-formylcyclohexylcarbamate as a tan glassy foam (220 mg). MS found: (M+Na)+=482.37.

Provenance & Evidence