77.0 g (164 mmol) of 2-[4-(4,4,4-trifluorobutoxy)phenyl]-5,6-dihydro-4H-1,3-dithiin-1-ium trifluoromethanesulfonate, are solubilised in 750 mL of dichloromethane. The solution is cooled down to −55° C. 42.5 g (245 mmol) of 4-bromophenol and 36.5 ml (262 mmol) of triethylamine dissolved in 300 ml of dichloromethane is added to the previous solution. The solution is cooled down to −70° C. and stirred for 45 minutes. 120 ml (736 mmol) of triethylamine trihydrofluoride are added to the mixture. A solution of 8.43 ml (164 mmol) of bromine in 60 ml of dichloromethane is added at this temperature. The reaction is stirred for one hour. The reaction is quenched by addition of NaHCO3. The organic phase is washed repeatedly with water, dried over sodium sulfate, filtrated and concentrated under reduced pressure. Chromatography of the residue on 400 g silica gel using toluene: ethyl acetate 95:5 as eluent yielded 47 g of 1-bromo-4-{difluoro[4-(4,4,4-trifluorobutoxy)phenyl]methoxy}-benzene.
