Boron tribromide → (6-Hydroxy-benzo[b]thiophen-3-yl)-acetic acid ethyl ester

Participants

Reaction Steps

To a −78° C. solution of (6-methoxy-benzo[b]thiophen-3-yl)-acetic acid ethyl ester (3.81 g, 15.22 mmol) in dichloromethane (50 mL) is added boron tribromide (38.1 mL, 38.1 mmol) dropwise. The mixture is allowed to warm to room temperature and stirred for 16 hours. The mixture is cooled to 0° C. and quenched with water (100 mL). The organic layer is separated, and the aqueous layer is extracted with EtOAc (50 mL). The combined organic layers are dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude product is purified by flash chromatography eluting with 30-40% EtOAc/Hexanes. The appropriate fractions are combined and concentrated under reduced pressure to afford the title compound (3.35 g, 93%). ES/MS m/e 237.0 (M+1); 235.0 (M−1).

Provenance & Evidence