A mixture of 3,5-dioxocyclohexanecarboxylic acid (1.00 g, 6.41 mmol), 3-(trifluoromethyl)aniline (880 μL, 1.14 g, 4.05 mmol), Ytterbium(III) trifluormethanesulfonate (20 mg, 32 μmol, 0.5 mol %) and N,N-dimethylformamide (3 mL) is stirred at room temperature over night. Water and aqueous sodium hydroxide are added and the mixture is washed with diethyl ether. The organic layer is discarded, and the aqueous layer is acidified with aqueous hydrogen chloride and extracted with diethyl ether. The organic layer is dried over Na2SO4 and concentrated under reduced pressure. Yield: 1.30 g; ESI mass spectrum [M+H]+=300, Retention time HPLC: 1.08 min (V001—006).
