A mixture of butylmagnesium chloride (1 mL, 1 mmol, 2.0 M in ether) and di-isopropyl amine (0.279 mL, 2 mmol) in dry THF (5 mL) was stirred for 4 h under inert atmosphere at room temperature. A solution of tert-butyl 4-[1-(phenylsulfonyl)-1H-indol-4-yl]-1-piperazinecarboxylate (220 mg, 0.5 mmol) in THF (2 mL) was added slowly and the resulting mixture stirred for 2 h at room temperature. A solution of iodine (380 mg, 2.2 mmol) in THF (2 mL) was added dropwise and the mixture was stirred overnight. After evaporation of the solvent in vacuo, the residue was treated with an aqueous solution of NH4Cl (10 mL). The mixture was extracted with CH2Cl2 (3×10 mL) and the combined organic layers were dried (MgSO4) and concentrated in vacuo. The residue was purified by column chromatography (SiO2) using CH2Cl2 as eluent to give, 100 mg (35%). 1H NMR (500 MHz, CDCl3) δ 8.05-7.80 (m, 3H), 7.60-7.35 (m, 3H), 7.19 (t, J=8 Hz, 1H), 6.98 (s, 1H), 6.72 (d, J=8 Hz, 1H), 3.62 (m, 4H), 3.05 (m, 4H), 1.47 (m, 9H); MS (ESI+) for m/z 568 (M+H)+.
