General procedure for the synthesis of (4-(2-hydroxyethyl)phenyl)boronic acid from 4-bromophenylethanol: To a stirred solution of 4-bromophenylethanol (5.00 g, 24.9 mmol) in THF (80 ml) was slowly added a hexane solution (39.8 ml, 59.7 mmol) of 1.5 M n-butyllithium (n-BuLi) at -78 °C for 30 minutes. The reaction temperature was maintained at -78 °C and after 1 h of reaction, a THF (20 ml) solution of triisopropoxyboron (B(OiPr)3, 8.61 ml, 37.3 mmol) was slowly added. The reaction mixture was gradually warmed up to room temperature and treated with 2M hydrochloric acid (HCl, 100 ml) for 1 hour. After completion of the reaction, the reaction mixture was extracted with dichloromethane (CH2Cl2), the organic phase was dried with anhydrous magnesium sulfate (MgSO4) and filtered. The filtrate was concentrated by vacuum evaporation and the residue was purified by silica gel column chromatography with dichloromethane/methanol as eluent (CH2Cl2/MeOH = 20/1, v/v) to afford 2.61 g of the target product (4-(2-hydroxyethyl)phenyl)boronic acid in 63% yield. The product was characterized by 1H-NMR (CD3OD): δ 7.64-7.48 (2H, m), 7.19-7.13 (2H, m), 3.70 (2H, t, J = 7.2 Hz), 2.77 (2H, t, J = 7.2 Hz). Mass spectrum (ESI) m/z: 165 ([MH]-).
