The general procedure for the synthesis of 5-bromo-3-isopropenylpyridine from 3,5-dibromopyridine and isopropenylboronic acid pinacol ester was as follows: dichloromethane adducts of [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride (98.0 mass %), potassium acetate hydrate (7.4997 mmol; 3.7 mL), sodium carbonate decahydrate (7.4997 mmol; 3.7 mL), acetonitrile (15 mL), and 3,5-dibromopyridine (4.9998 mmol; 1184.4 mg) with 2-isopropenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (4.9998 mmol; 840.0 mg; 0.940 mL) were placed in a pressure tube and under microwave conditions at 120 °C Heating for 3 min. After completion of the reaction, the mixture was cooled to room temperature. A layering operation was performed and the aqueous layer was extracted with ethyl acetate (EtOAc). The organic layers were combined and concentrated. The residue was purified by silica gel column chromatography using a gradient elution with a dichloromethane (DCM) solution of 0 to 10% methanol (MeOH) to afford 5-bromo-3-isopropenylpyridine as a dark tan solid (512.6 mg, 52% yield).
