To a 500 mL sealed tube was added m-bromobenzaldehyde (9.25 g, 50.0 mmol), potassium acetate (9.8 g, 100 mmol), bis(pinacolato)diborane (15.3 g, 60.3 mmol) and 1,4-dioxane (50 mL). The reaction system was degassed with nitrogen for 15 min. Subsequently, Pd(dppf)Cl2 (0.82 g, 1.0 mmol) was added and the reaction mixture was stirred at 90°C overnight. Upon completion of the reaction, the mixture was filtered through a diatomaceous earth pad and the filtrate was separated by extraction with water and ethyl acetate. The organic layers were combined, dried with anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by column chromatography to afford 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde (11.5 g, 99% yield) as a colorless liquid.LCMS (M + H)+: 233.2; 1H NMR (DMSO-d6, 300 MHz) δ: 10.06 (s, 1H), 8.21 (s, 1H), 8.01-8.04 (d, 1H), 7.96-7.99 (d, 1H), 7.61-7.66 (t, 1H), 1.33 (s, 12H).
