A solution of 2-(3-iodo-6-methyl-1H-indazol-1-yl)-N,N-dimethylethanamine (450 mg, 1.4 mmol) in 20 mL of dry THF was cooled to −20° C. under nitrogen atmosphere, isopropylmagnesium chloride (1.4 mL, 2.8 mmol, 2 M in THF) was added and stirred for 15 min at −20° C. Then tributylchlorostannane (0.8 mL, 2.8 mmol) was added and allowed to warm to room temperature. The reaction was cooled in an ice bath and quenched with saturated ammonium chloride solution, extracted with ethyl acetate (3×30 mL), combined organics dried with sodium sulfate and concentrated to give 1.4 g of crude N,N-dimethyl-2-(6-methyl-3-(tributylstannyl)-1H-indazol-1-yl)ethanamine as an oil which was used in the next step directly without further purification.
