[F:1][C:2]1[CH:7]=[CH:6][C:5]([C:8](=[O:15])[CH2:9][C:10]([O:12][CH2:13][CH3:14])=[O:11])=[CH:4][CH:3]=1.[Br:16][C:17]1[CH:22]=[CH:21][C:20](O)=[CH:19][CH:18]=1.C(OOC(C)(C)C)(C)(C)C>ClCCCl>[Br:16][C:17]1[CH:18]=[CH:19][C:20]2[O:15][C:8]([C:5]3[CH:4]=[CH:3][C:2]([F:1])=[CH:7][CH:6]=3)=[C:9]([C:10]([O:12][CH2:13][CH3:14])=[O:11])[C:21]=2[CH:22]=1A solution of ethyl 3-(4-fluorophenyl)-3-oxopropanoate (130 g, 0.6 mol), 4-bromophenol (311 g, 1.8 mol) and FeCl3.6H2O (19.5 g, 0.09 mol) in DCE (700 mL) was heated to reflux, and then 2-(tert-butylperoxy)-2-methylpropane (193 g, 1.32 mol) was added dropwise under nitrogen. After 6 hours of refluxing, the mixture was cooled to RT, quenched with saturated NaHSO3 and extracted with dichloromethane. The organic phases were washed with water, brine and dried over Na2SO4, filtered and concentrated in vacuo. The resulting residue was purified using column chromatography (petroleum ether/dichloromethane=15/1) to provide the crude product, which was crystallized from cold MeOH to provide ethyl 5-bromo-2-(4-fluorophenyl)benzofuran-3-carboxylate (37 g, yield: 14.3%) as solid. 1H-NMR (CDCl3, 400 MHz) δ 8.12 (s, 1H), 7.97˜8.01 (m, 2H), 7.37 (d, J=4.0 Hz, 1H), 7.32 (d, J=8.0 Hz, 1H), 7.11 (t, J=8.0 Hz, 2H), 4.32˜4.38 (m, 2H), 1.36 (t, J=8.0 Hz, 3H). MS (M+H)+: 363/365.
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