manganese(IV) oxide in hexane; dichloromethane 26 h; Ambient temperature; Yield given;

1: 90 percent / O3, Me2S / CH2Cl2 2: 82 percent / CH2Cl2 / 4 h / Heating 3: tetrahydrofuran / 0.67 h / 45 °C 4: MnO2 / hexane; CH2Cl2 / 26 h / Ambient temperature View Scheme

1: 82 percent / CH2Cl2 / 4 h / Heating 2: tetrahydrofuran / 0.67 h / 45 °C 3: MnO2 / hexane; CH2Cl2 / 26 h / Ambient temperature View Scheme