[F:1][C:2]([F:12])([F:11])[C:3](=[O:10])[CH2:4][C:5]([O:7][CH2:8][CH3:9])=[O:6].[C:13](=O)([O-])[O-].[Cs+].[Cs+].C1(C)C=CC(S(OC)(=O)=O)=CC=1>CN(C=O)C.O>[CH2:8]([O:7][C:5](=[O:6])[CH:4]=[C:3]([O:10][CH3:13])[C:2]([F:11])([F:12])[F:1])[CH3:9]To a solution of ethyl 4,4,4-trifluoroacetoacetate (12 mL, 82 mmol) in DMF (80 mL) is added cesium carbonate (26.4 g, 82 mmol). The reaction mixture is heated to 70° C. A solution of methyl p-toluenesulfonate (13.5 mL, 90 mmol) in DMF (30 mL) is then added dropwise during 30 min and the reaction mixture is stirred for an additional 1 hr. After cooling to room temperature, the reaction mixture is diluted with H2O (150 mL) and extracted with Et2O (2×150 mL). The organic extracts are combined and washed with H2O and brine, then dried (Na2SO4), filtered and concentrated to afford the title compound (9.0 g, 56%) as an oil which is used without further purification.
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