1: 86 percent / P2S5 / CH2Cl2 / 40 h / Heating 2: 93 percent / PhCO2H, aq. KMnO4, benzyltriethylammonium chloride / CH2Cl2 / 15 h / Ambient temperature 3: 600 °C / 0 Torr View Scheme

hydrogenchloride 6 h; Heating;