1: 100 percent / Al2O3 / diethyl ether; methanol 2: various solvent(s) / 1.5 h / 140 °C 3: CH2Cl2 4: 60 percent / benzene / 1 h / 45 °C View Scheme

With  3-chloro-benzenecarboperoxoic acid in  dichloromethane  Ambient temperature;