DIBALH (100 mL, 1M toluene solution, 100 mmol) was added in batches to a suspension of methyl 4-bromo-3-hydroxybenzoate 70 (6.97 g, 30.2 mmol) in dichloromethane (360 mL) at 0 C. Significant gas escape was observed. The resulting mixture was warmed to room temperature and stirred for 2.75 hours. Thereafter, the reaction mixture was quenched by addition of saturated aqueous sodium potassium tartrate (600 mL) and saturated aqueous ammonium chloride (100 mL). The resulting two-phase mixture was stirred vigorously for 2 hours and then extracted with dichloromethane (3). The organic layer was dried with Na2SO4 and filtered to give 2-bromo-5-hydroxymethylphenol.
