1: 83 percent / pyridine / Ambient temperature 2: 95 percent / p-TsOH, MeOH / 0.05 h / 50 °C 3: 77 percent / aluminium isopropoxide / toluene; cyclohexanone / 20 h / Heating 4: 28 percent / KMnO4, triethylbenzylammonium chloride (TEBACl) / CH2Cl2 / Ambient temperature View Scheme

1: 83 percent / pyridine / Ambient temperature 2: 47 percent / KMnO4, triethylbenzylammonium chloride (TEBACl) / CH2Cl2 / Ambient temperature 3: p-TsOH, methanol / 0.33 h / 50 °C 4: pyridine View Scheme