1: 77 percent / trifluoroacetic anhydride / CH2Cl2 / 2 h / Heating 2: 52 percent / tetrahydrofuran / 1 h / -78 °C 3: 70 percent / 4N KOH / methanol / 5 h / Heating View Scheme

[bis(acetoxy)iodo]benzene; lithium iodide in dichloromethane; 2,2,2-trifluoroethanol T=20°C; 3 h;