1: pyridinium p-toluenesulfonate / ethanol / 1 h / 60 °C 2: RuCl2(tricyclohexylphosphine)2(benzylidene) / toluene / 23 h / 80 °C / Inert atmosphere 3: 1-hydroxy-3H-benz[d][1,2]iodoxole-1,3-dione / dichloromethane; dimethyl sulfoxide / 0.5 h / 20 °C / Inert atmosphere 4: aluminium(III) iodide; tetra-(n-butyl)ammonium iodide / benzene / 10 °C View Scheme