A sample of (3R,4S)-tert-butyl 3-(isopropylsulfonylmethyl)-4-((S)-2-oxo-3-(3-(trifluoromethyl)benzamido)pyrrolidin-1-yl)piperidine-1-carboxylate (0.688 g) was dissolved in CH2Cl2 (10 mL) prior to the addition of trifluoroacetic acid (0.92 mL, 11.9 mMol). After 4 h, the reaction was made basic with saturated NaHCO3. Extracted with CH2Cl2. The organic layer was washed with brine and dried (MgSO4). Concentrated and dried in vacuo to yield the desired product, N-((S)-1-((3R,4S)-3-(isopropylsulfonylmethyl)piperidin-4-yl)-2-oxopyrrolidin-3-yl)-3-(trifluoromethyl)benzamide) (0.482 g, yield=85%). MS found: (M+H)+=476.31
