Cesium fluoride → 3-Bromo-4-(4'-(trifluoromethyl)phenyl)furan-2-(5H)-one

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Reaction Steps

A mixture containing 3,4-dibromofuran-2(5H)-one (0.518 g, 2.142 mmol), 4-trifluoromethylphenylboronic acid (0.509 g, 2.680 mmol), trans-dichlorobis(triphenylphosphine)palladium (II) (0.069 g, 9.831×10−2 mmol), tetrabutylammonium iodide (0.038 g, 1.029×10−1 mmol) and cesium fluoride (0.872 g, 5.740 mmol) in toluene (10 mL) and water (10 mL) was stirred at room temperature for 72 h under nitrogen. Brine (50 mL) was added and the product extracted with ethyl acetate (3×50 mL). The organic fractions were combined, washed with brine (3×50 mL), dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure to give an orange solid. The resulting solid was chromatographed (silica gel: eluent 25:75 dichloromethane/light petroleum) to give 3-bromo-4-(4′-(trifluoromethyl)phenyl)furan-2-(5H)-one 16 (0.312 g, 47%) as a pale yellow powder. Further purification by recrystallisation from dichloromethane/light petroleum furnished colourless needles, (ref. PDS-2-115); 1H NMR (CDCl3, 300 MHz) δ 7.94 (d, 2H, J=8.3 Hz, H3′, H5′), 7.78 (d, 2H, J=8.3 Hz, H2′, H6′), 5.21 (s, 2H, H5).

Provenance & Evidence