1: 100 percent / p-toluenesulfonic acid hydrate / benzene / 3.5 h / Heating 2: 48 percent / 190 - 200 °C 3: 1.) n-butyllithium / 1.) THF, hexane, -78 deg C, 5 min, 2.) THF, hexane, -78 deg C, 1.0 h View Scheme