1: 62 percent / 57-80percent m-chloroperbenzoic acid / CHCl3 / 24 h / Ambient temperature 2: 48 percent / Ac2O / 12 h / Heating 3: 32 percent / POCl3 / dimethylformamide / 18 h / Heating 4: 1.) Pd(PPh3)4, 2.) K2CO3 / 1.) THF, room temp., 5 min, 2.) THF, water, reflux, 24 h View Scheme