To a mixture of 1-bromo-5-isopropoxy-2-methyl-4-nitrobenzene (Step 2, 1 g, 3.65 mmol), pyridine-4-boronic acid (490 mg, 4 mmol), 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (300 mg, 0.73 mmol) and potassium phosphate (1.55 g, 7.3 mmol) in mixed solvent of dioxane (15 mL) and water (7.5 mL) was added tris(dibenzylidene-acetone)dipalladium (0) (334 mg, 0.36 mmol). This mixture was sealed and purged with nitrogen for 3 minutes and then heated at 120° C. for 5 hours. The mixture was cooled to room temperature, filtered, and the filtrate was concentrated. After concentration, the crude product was purified with silica gel flash column chromatography (60% ethyl acetate in hexanes) to afford 4-(5-isopropoxy-2-methyl-4-nitrophenyl)pyridine a as yellow solid: ESMS m/z 273.2 (M+H+).
