To 1-cyclobutyl-6-difluoromethoxy-1H-indole-3-carbonitrile (830 mg, 3.17 mmol) in THF (10 mL) was added tributyltin iodide (1.13 mL, 4.04 mmol) and the solution cooled to −78° C. A solution of LDA (1.5M in cyclohexane, 3.4 mL, 5.1 mmol) was added dropwise. After complete addition the bath was removed and the mixture stirred at room temperature for 1 hour. THF was then removed under vacuum and the residue filtered through silica gel using CH2Cl2 as an eluant and the mixture concentrated. The residue was purified by flash chromatography using 30-50% CH2Cl2/hexanes to provide 1-cyclobutyl-6-difluoromethoxy-2-tributylstannanyl-1H-indole-3-carbonitrile as a clear, colorless oil (1.23 g, 70%).
