in nitrobenzene T=200°C; 2 h;

Multi-step reaction with 3 steps 1: 1.) TFAA / 2.) CH2Cl2, room t., 90 h; addition at 0, 6 and 48 h2: 70 percent / silver(II)oxide / dioxane / Ambient temperature3: 65 percent / BCl3(7 mol equiv) / CH2Cl2 / 3 h / 0 °C / then to room t.  

Multi-step reaction with 2 steps 1: 70 percent / silver(II)oxide / dioxane / Ambient temperature2: 65 percent / BCl3(7 mol equiv) / CH2Cl2 / 3 h / 0 °C / then to room t.