The general procedure for the synthesis of 2,6-dimethyl-pyridine-4-boronic acid from 4-bromo-2,6-dimethylpyridine and triisopropyl borate was as follows: in a dry reaction flask, 4-bromo-2,6-dimethylpyridine (100 mg, 0.54 mmol) and triisopropyl borate (149 μL, 0.65 mmol) were dissolved in anhydrous THF (5 mL). The reaction system was cooled to -78 °C under nitrogen protection, followed by the slow dropwise addition of a hexane solution of 2.5 M n-BuLi (0.26 mL, 0.65 mmol). After the dropwise addition, the reaction was kept at -78 °C for 30 min. Subsequently, the reaction mixture was slowly warmed to room temperature and stirring was continued for 1 hour. After completion of the reaction, 1 N HCl (5 mL) was added to the reaction system and stirred for 30 min at room temperature. Next, the reaction solution was adjusted to alkaline (pH ~9) with 1 N NaOH and then extracted with EtOAc (3 × 10 mL). The organic phases were combined, dried with anhydrous Na2SO4, filtered and concentrated under reduced pressure to afford 2,6-dimethyl-pyridine-4-boronic acid (30.0 mg, 0.20 mmol, 37% yield) as a white solid.
