Synthesis
General procedure: to a 50 mL solution of 1,4-dioxane was added sequentially 2-benzyloxy-5-bromopyridine (3.76 g, 14.2 mmol, 1.0 eq.), pinacol ester of bis(boronic acid) (4.34 g, 17.1 mmol, 1.2 eq.), potassium acetate (3.48 g, 35.5 mmol, 2.5 eq.), and [1,1'-bis(diphenylphosphino) ferrocene]palladium dichloride (1.16 g, 1.4 mmol, 0.1 eq.). The reaction mixture was heated to 100 °C under nitrogen protection and refluxed overnight. After completion of the reaction, the reaction mixture was concentrated and dried, and the residue was purified by column chromatography (eluent: petroleum ether/dichloromethane=2:1) to afford 6-benzyloxypyridine-3-boronic acid pinacol ester (2.63 g, 59.5% yield).
