A mixture of 1-benzenesulfonyl-2-[2-cyclopentyl-1-(4-methanesulfonyl-phenyl)-vinyl]-5-ethanesulfinyl-1H-pyrrolo[2,3-b]pyridine (56 mg, 0.096 mmol) and a solution of tetrabutylammonium fluoride in tetrahydrofuran (1 M, 3.85 mL, 3.85 mmol) was stirred for 12 h at room temperature. The mixture was poured into brine (5 mL), extracted with ethyl acetate (2×20 mL), washed with a saturated aqueous ammonium chloride solution (3×10 mL), dried over anhydrous sodium sulfate and then concentrated in vacuo to give 2-[2-cyclopentyl-1-(4-methanesulfonyl-phenyl)-vinyl]-5-ethanesulfinyl-1H-pyrrolo[2,3-b]pyridine (37 mg, 88%) as a solid which was used in the next step without purification: LC/MS m/e calcd for C23H26N2O3S2 [M+H]+ 443.6, observed 443.1.
