Boron tribromide → 3-Bromo-5-ethanesulfonyl-phenol

Participants

Reaction Steps

To a solution of 1-bromo-3-ethanesulfonyl-5-methoxy-benzene (670 mg, 2.4 mmol) in dichloromethane (25 mL) was added boron tribromide (4.8 mL, 4.8 mmol) in dichloromethane (1.0 M) at −70° C. Then, the resulting brown solution was stirred for 30 minutes at this temperature and then the cooling bath was removed to warm to room temperature and stirred for 15 h at which time TLC analysis of the mixture indicated the absence of starting material. The reaction mixture was quenched with water slowly (50 mL). The two layers were separated and the aqueous layer was extracted with dichloromethane (50 mL). The combined organic layer was washed with brine solution (100 mL) and the organic layer was dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo. The crude residue was purified by using an ISCO 40 g column, eluting with 0-50% ethyl acetate in hexanes to obtain 3-bromo-5-ethanesulfonyl-phenol (576 mg, 90.5%) as a colorless viscous oil: ES(+)-HRMS m/e calcd for C8H9BrO3S (M+H)+ 264.9529, found 264.9528.

Provenance & Evidence