Water → 4-(Bromomethyl)-3,5-difluoropyridine

To a solution of (3,5-difluoropyridin-4-yl)methanol (3.5 mmol) in anhydrous chloroform (15 mL) was added dropwise a solution of phosphorus tribromide (330 μL, 3.5 mmol) in anhydrous chloroform (5 mL) at 0° C. The mixture was stirred for 6 hours at room temperature. Water was added, and the reaction was extracted 3 times with dichloromethane. The combined organic phases were washed with brine and dried over magnesium sulfate. After evaporation of the solvent, 4-(bromomethyl)-3,5-difluoropyridine was obtained as pale yellow solid (600 mg, 83% yield for 2 steps) and used in the next step without purification; 1H NMR (400 MHz, MeOd4): δ 4.59 (s, 2H), 8.42 (s, 2H).