To a solution of4-chloro-5-bromo-7H-pyrrolo[2,3-d]pyrimidine (0.92 g, 4.0 mmol) in tetrahydrofuran (25mL) was added n-BuLi (2.5 Msolution in hexane, 3.48 mL) dropwise at –78 °C,and the reaction mixture was stirred at -78 °Cfor an additional 30 min. To thissolution was added trimethylstannyl chloride (0.88 g, 4.4 mmol) in tetrahydrofuran (8 mL) dropwiseover a period of 10 min. The reactionmixture was allowed to warm to room temperature and was stirred overnight. Saturated aqueous ammonium chloride (60 mL)was added and extracted with ethyl acetate (3 ×70 mL). The combined organic extracts were washedwith brine, dried over Na2SO4, and evaporated to dryness. The residue was purified over silica gel togive the desired stannane (0.80 g,63%) as a colorless solid.
To a solution of this compound (1.97 g, 6.20 mmol) in acetonitrile (60mL) was added 1-(chloromethyl)- 4-fluoro-1,4- diazoniabicyclo[2.2.2]octanebis(tetrafluoroborate) (Selectfluor, 2.40 g, 6.5 mmol) in one portion, and the reaction mixture wasstirred at room temperature for 7 h. Theprecipitate was filtered off, and the filtrate was evaporated in vacuo. The residue was purified on silica gel usingethyl acetate/hexane (3:7) as the eluent to give the desired compound (0.22 g, 21%) as a colorless solid.
【 Eldrup, A. B. et al. J. Med. Chem. 2004, 47, 5284.】