Hydrogen Peroxide → Phenol, 5-bromo-2-fluoro-

Participants

Reaction Steps

A solution of 5-bromo-2-fluorobenzeneboronic acid (25 g, 114 mmol) in tetrahydrofuran was treated with hydrogen peroxide (7.8 ml of a 35 wt % solution in water) then with sodium hydroxide (1.4 ml of a 4N solution in water). A mild exotherm caused the internal temperature to reach 40° C. This mixture was left to stir at ambient temperature for 14 h then treated with manganese dioxide (200 mg) and stirring was continued for 90 min before filtering the reaction (GF/A filter paper). The filtrate was concentrated on a rotary evaporator and the residue partitioned between ether (400 ml) and water. The organics were washed with more water and brine, and dried over anhydrous magnesium sulphate. Filtration and evaporation to dryness afforded 5-bromo-2-fluorophenol (19.7 g, 90%) as a colourless liquid: δH (400 MHz, d6-DMSO) 6.93-6.97 (1H, m), 7.09-7.14 (2H, m), 10.36 (1H, br).

Provenance & Evidence