A solution of 1-bromo-4-(chloro(isocyanato)methyl)benzene (400 mg, 1.62 mmol) in dichloromethane (2.5 mL) is added to a solution of 3-(3-(difluoromethyl)phenylamino)-cyclohex-2-enone (intermediate 32, 385 mg, 1.62 mmol) in dichloromethane (2.5 mL). The mixture is heated at reflux for 2 h and cooled to room temperature. Water is added and the mixture is extracted twice with dichloromethane. The combined organic layers are dried over Na2SO4 and concentrated under reduced pressure. The residue is purified by flash chromatography on silica (gradient cyclohexane/ethyl acetate 80:20 to ethyl acetate. Yield: 350 mg; ESI mass spectrum: [(79Br)-M+H]+=447, [(81Br)-M+H]+=449; Retention time HPLC: 0.61 min (X012_S01).
