To a solution of 6-bromo-3,4-dihydro-2H-[1,8]naphthyridine-1-carboxylic acid amide (500 mg, 2.0 mmol) in a mixture of 1,4-dioxane (9 mL) and water (1 mL) is added 5-formylpyridine-3-boronic acid pinacol ester (501 mg, 2.1 mmol), sodium carbonate (290 mg; 2.7 mmol), and 1,1′-bis(diphenylphosphino)ferrocenedichloropalladium (II) (159 mg, 0.20 mmol). The resultant mixture is stirred at 100° C. for 2 h. EtOAc is added and the mixture is washed with saturated aqueous sodium bicarbonate solution, brine and is dried (MgSO4). The solvent is evaporated and the crude product is purified by silica gel column (0-10% MeOH in DCM) to afford 6-(5-formyl-pyridin-3-yl)-3,4-dihydro-2H-[1,8]naphthyridine-1-carboxylic acid amide (342 mg).
