(1) Synthesis of 2-(pyridin-3-yl)benzaldehyde: o-Bromobenzaldehyde (250 μL, 2.14 mmol), sodium carbonate (270 mg, 2.55 mmol) and pyridine-3-boronic acid (289 mg, 2.35 mmol) were suspended in 4.2 mL of a solvent mixture of N,N-dimethylformamide and water (2:1, v/v/v/v/v) protected by nitrogen. Palladium acetate (24 mg, 0.11 mmol) and triphenylphosphine (115 mg, 0.44 mmol) were subsequently added. The reaction mixture was stirred at 110 °C overnight. After completion of the reaction, the mixture was filtered and the filtrate was diluted with chloroform and washed with brine and dried over anhydrous magnesium sulfate. After filtration, the filtrate was concentrated under reduced pressure and the residue was purified by silica gel column chromatography (eluent: chloroform/methanol = 99/1 to 95/5) to afford the target product 2-pyridin-3-ylbenzaldehyde as a white powder (250 mg, 64% yield).
