To a solution of 4-(pentafluorothio)aniline (15.0 g, 68.4 mmol) and ice (40.0 g) in hydrochloric acid (12M, 30 ml) was added a solution of sodium nitrite (5.0 g, 72.5 mmol) in water (120 ml) at 0 ℃. After stirring for 2 min, the mixture was added to potassium iodide (13.0 g, 78.3 mmol) in water (120 ml), ensuring the temperature did not rise above 10 C. The reaction mixture was stirred at 0 ℃. for 10 min and then at room temperature for 60 h. The mixture was extracted with diethyl ether (2×100 ml), and the combined extracts were washed with brine, dried (MgSO4) and concentrated in vacuo. The residue was purified by column chromatography (silica, 300 g), eluting with diethyl ether/cyclohexane [1:10]. The appropriate fractions were combined and concentrated to give 4-Iodophenylsulphur pentafluoride(16.6 g).
