Potassium Carbonate → 1-Bromo-3-fluoro-5-(1,1,2,2-tetrafluoroethoxy)benzene

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To a solution of 3-bromo-5-fluorophenol (104 mmol crude) and iodo-1,1,2,2,-tetrafluoroethane (28.4 g, 125 mmol) in DMSO (80 mL) was added K2CO3 (57.0 g, 420 mmol). The reaction mixture was sealed in a thick walled glass pressure round bottom flask and heated at 70° C. for 18 h. The reaction mixture was allowed to cool to room temperature, diluted with water (500 mL) and extracted with ether (3×200 mL). The combined ether layers were washed with 1N NaOH (2×200 mL), water (2×200 mL) and saturated NaCl (200 mL). The organic layer was dried over sodium sulfate, filtered and concentrated. The residue was dissolved in ether (150 mL) and filtered through a plug of activated basic alumina. The filtrate was concentrated to give 1-bromo-3-fluoro-5-(1,1,2,2-tetrafluoroethoxy)benzene as a pale yellow oil (27.2 g, 88% for two steps) which was used without further purification LCMS: RT=1.91 min, [M+H] No Ionizable peak (Phenomenex Luna C18 column, 4.6×30 mm eluting with 10-90% MeOH/H2O over 2 minutes containing 0.1% TFA; 5 mL/min, monitoring at 220 nm); NMR: 400 MHz 1H (CDCl3) 7.19 ppm, 2H, m; 6.92 ppm, 1H, d, J=8.35 Hz; 5.88 ppm, 1H, tt; J=52.95 Hz and 2.64 Hz.

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