2-(3,5-Dimethoxy)-phenyl-4,4,5,5-tetramethyl-(1,3,2)-dioxaborolane

73183-34-3

151-10-0

365564-07-4

Under nitrogen protection, 1,3-dimethoxybenzene (69.1 mg, 0.5 mmol), pinacol ester of bisboronic acid (126.9 mg, 0.5 mmol), methoxy-1,5-cyclooctadienyl iridium dimer (3.4 mg, 0.005 mmol, 1 mol%), and borane pyridine ligand (4.0 mg, 0.01 mmol, 2 mol%), followed by the addition of cyclopentyl methyl ether (1 mL to give a 1,3-dimethoxybenzene concentration of 0.5 mol/L). The reaction mixture was stirred at 100°C for 16 hours. After completion of the reaction, the solvent cyclopentyl methyl ether was removed by rotary evaporation (20-40°C). The crude product was purified by column chromatography (using 200-300 mesh silica gel with a silica gel to sample mass ratio of 50-100:1 and an eluent that was a mixture of petroleum ether and ethyl acetate at a volume ratio of 20-50:1) to give 3,5-dimethoxyphenylboronic acid pinacol ester as a colorless solid (125 mg, 99% yield).