Hydrochloric Acid → (2-Hydroxyphenyl)boronic acid

Part B: 2-Bromophenol (10.0 g, 57.8 mmol) was dissolved in dry THF (100 ml) in a dry 250 ml flask flushed with nitrogen. The mixture was chilled in a dry ice/2-propanol bath, n-butyl lithium (51 ml of a 2.5M solution in hexanes, 127.2 mmol) was added then the cooling bath was exchanged for an ice-water bath. The reaction was stirred for an hour at 0° C. then trimethyl borate (6.9 ml, 60.7 mmol) was added to the slurry which became homogeneous after a few minutes. The mixture was stirred at room temperature overnight then treated with 2N aqueous HCl to pH 3, mixed well for 30 minutes and extracted with ether (3×25 ml). The organic materials were combined, dried (MgSO4) then concentrated under reduced pressure which gave 7.6 g (91%) of 2-hydroxybenzeneboronic acid as a white solid, m.p. 156°-158° C.