Mercury(II) chloride (538 mg, 1.98 mmol) was added to a solution of tert-butyl [(3R,6S)-6-(2,6-difluorophenyl)-2-thioxoazepan-3-yl]carbamate (353 mg, 0.99 mmol), 4,4,4-trifluoro-2-hydroxybutan-1-aminium chloride (498 mg, 2.77 mmol), and triethylamine (0.61 mL, 4.36 mmol) in ethanol (10 mL) at 55° C. After 2 h, the reaction was allowed to cool to ambient temperature. The mixture was filtered and concentrated. Saturated aqueous sodium bicarbonate was added and the mixture was extracted with dichloromethane (2×). The combined organic extracts were dried over magnesium sulfate, filtered, and concentrated to give the title compound. MS 466.2 (M+1).
