Trifluoroacetic acid → benzyl (S)-1-((1S,2R,4R)-4-(tert-butylamino)-2-(methylsulfonamido)cyclohexyl)-2-oxopyrrolidin-3-ylcarbamate

Participants

Reaction Steps

A sample of 2-(trimethylsilyl)ethyl (1R,2S,5R)-2-((S)-3-benzyloxycarbonylamino-2-oxopyrrolidin-1-yl)-5-(tert-butylamino)cyclohexylcarbamate and its 5S diastereomer (100 mg, 0.183 mmol; see Example 11, Step 4) was dissolved in dichloromethane (2 ml) prior to the addition of trifluoroacetic acid (2.54 ml, 32.9 mmol). After 30 min, the solution was concentrated in vacuo. The residue was dissolved in dichloromethane (3 ml) prior to the addition of triethylamine (0.100 ml, 0.720 mmol) and methanesulfonyl chloride (0.018 ml, 0.234 mmol). After 2 h, this was washed with sat NaHCO3 solution and the organic layer was dried (Na2SO4), filtered and concentrated to afford benzyl (S)-1-((1S,2R,4R)-4-(tert-butylamino)-2-(methylsulfonamido)cyclohexyl)-2-oxopyrrolidin-3-ylcarbamate as a mixture with its 4S diastereomer (66 mg, 0.137 mmol, 76% yield). LC/MS found [M+H]+=481.22.

Provenance & Evidence