In a round-bottomed flask, 5-difluoromethoxy-3-iodo-1H-indazole (200 mg, 0.6 mmol) was dissolved in THF (3.6 ml) and sodium hydride (60% in mineral oil, 64 mg, 1.6 mmol) was added. The reaction mixture was stirred at room temperature for 10 min then cooled to −16° C. (NaCl/ice bath) and isopropylmagnesium chloride (2.0 M in THF, 0.46 ml, 0.920 mmol) was added dropwise. The reaction mixture was stirred at −16° C. for 30 min then tributylchlorostannane (0.22 ml, 0.81 mmol) was slowly added. The reaction mixture was allowed to warm to room temperature and stirred for 1 h then quenched with saturated NH4Cl— solution and extracted with EtOAc (2×). The combined organic layers were washed with water and brine then dried over sodium sulfate, filtered and concentrated to give 5-difluoromethoxy-3-tributylstannanyl-1H-indazole as a yellow oil which was used without further purification.
