1: 72 percent / CrO3; pyridine / CH2Cl2 / 25 h / 20 °C 2: 95 percent / 5,10,15,20-tetraphenylporphyrin; O2 / CCl4 / 20 h / 20 °C / Irradiation 3: 16 percent / toluene / 24 h / 131 °C View Scheme