Add LDA (1.5 equiv., 0.74 mL, 1.47 mmol) dropwise in the space of 5 min to azaindole 25 (0.3 g, 0.98 mmol) in THF (15 mL), stirred at −78° C., under N2. After stirring the reaction medium for 0.5 h, add Bu3SnCl dropwise (475 mg, 400 μL, 1.47 mmol) and stir the reaction medium for a further 0.5 h. Then allow the reaction medium to return to room temperature, stop the reaction with H2O, dilute with EtOAc (200 mL), wash with brine, dry (MgSO4) and concentrate. The residue is submitted to flash chromatography to give 26 (0.46 g, 79%) as a colorless oil: 1H NMR (CDCl3) δ 8.15 (d, 1H, J=5.1 Hz), 7.97 (dd, 2H, J=8.0, 1.5 Hz), 7.27 (d, 2H, J=8.4 Hz), 7.09 (d, 1H, J=5.2 Hz), 6.75 (s, 1H), 2.36 (s, 3H), 1.65-1.20 (m, 12H), 0.93 (t, 9H), TLC (EtOAc at 40%/heptane) Rf=0.65.
