[S:1]1[C:5]([CH2:6][CH2:7][OH:8])=[CH:4][C:3]2[CH:9]=[CH:10][CH:11]=[CH:12][C:2]1=2.[Br:13]Br.C([O-])(O)=O.[Na+]>C(Cl)(Cl)Cl>[Br:13][C:4]1[C:3]2[CH:9]=[CH:10][CH:11]=[CH:12][C:2]=2[S:1][C:5]=1[CH2:6][CH2:7][OH:8]To a cooled solution (0° C.) of 2-benzo[b]thiophen-2-yl-ethanol (5 g, 28.1 mmol) in CHCl3 (30 mL), bromine (1.73 mL, 33.7 mmol) was added dropwise. The reaction was stirred overnight while gradually being warmed to room temperature. Saturated NaHCO3 was added and the organic layer was separated. The aqueous layer was subsequently extracted with dichloromethane and the combined organic layers were dried (Na2SO4) and concentrated in vacuo to afford 2-(3-bromo-benzo[b]thiophen-2-yl)-ethanol in quantitative yield.
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