2.5 M solution of n-Bui in hexane (2.47 mL, 6.18 mmol) was added dropwise to a stirred and cooled (−78° C.) solution of azaindole 7 (1.088 g, 5.13 mmol) in THF (5.5 mL). After the mixture was stirred for 20 min at −78° C., neat PhSO2Cl (0.785 mL, 6.2 mmol) was added dropwise. The mixture turned brown. Stirring at −78° C. was continued for 0.5 b. Cooling bath was removed, the mixture was stirred at r.t. overnight, and separated between AcOEt:saturated aqueous NaHCO3 solution. The aqueous layer was extracted with AcOEt (2×5 mL). Combined organic solutions were washed with brine, dried (MgSO4), concentrated, and separated by means of SGC with hexane:AcOEt as eluent in gradient to afford 12 (1.6705 g, 92%) as white solid. 1H NMR (400 MHz, CDCl3) δ 6.66 (d, J=4.0 Hz, 1H), 7.08 (dddd, J=8.4, 8.0, 2.5, 1.1 Hz, 1H), 7.25 (ddd, J=9.9, 2.5, 1.7 Hz, 1H), 7.33 (ddd, J=7.8, 1.7, 1.1 Hz, 1H), 7.43 (ddd, J=8.0, 7.8, 6.0 Hz, 1H), 7.47-7.53 (m, 2H), 7.57-7.62 (m, 1H), 7.78 (d, J=4.0 Hz, 1H), 7.99 (d, J=2.2 Hz, 1H), 8.21-8.26 (m, 2H), 8.63 (d, J=2.2 Hz, 1H).
