In a pressure tube reactor, 4-bromo-2-fluorobenzaldehyde (500 mg, 2.46 mmol), 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bis(1,3,2-dioxaborolane) (938 mg, 3.69 mmol), Pd(dppf)2Cl2 (120 mg, 0.15 mmol), dppf (78 mg, 0.15 mmol) and KOAc (965 mg, 9.84 mmol) were added sequentially. Subsequently, 1,4-dioxane (8 mL) was added as solvent and the reaction was stirred at 85 °C for 13 h under nitrogen protection. Upon completion of the reaction, the reaction mixture was extracted several times with ethyl acetate and water, and the organic layers were combined and dried over anhydrous sodium sulfate to remove water. After concentration under reduced pressure, the product was purified by column chromatography (eluent: 20% ethyl acetate/hexane) to afford the target product 2-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde in 96% yield. The product was characterized by 1H-NMR (300 MHz, CDCl3): δ 10.38 (s, 1H), 7.85-7.81 (m, 1H), 7.67-7.65 (m, 1H), 7.57 (s, J = 10.4 Hz, 1H), 1.35 (s, 12H).
