samarium diiodide; diphenyldisulfane in tetrahydrofuran T=25°C; 1 h;

MoOBr3; dihydrogen peroxide; acetic anhydride; acetic acid T=50 - 70°C; 6 h;

1.1: O3 / CH2Cl2 / -78 - 20 °C 1.2: Me2S / CH2Cl2 / 5 h / 20 °C 1.3: 5.91 g / Ph3P / CH2Cl2 / 5 h / 20 °C 2.1: 100 percent / (PhS)2; SmI2 / tetrahydrofuran / 1 h / 25 °C View Scheme

1.1: p-TsOH / benzene / Heating 2.1: O3 / CH2Cl2 / -78 - 20 °C 2.2: Me2S / CH2Cl2 / 5 h / 20 °C 2.3: 5.91 g / Ph3P / CH2Cl2 / 5 h / 20 °C 3.1: 100 percent / (PhS)2; SmI2 / tetrahydrofuran / 1 h / 25 °C View Scheme

1.1: diethyl ether / 25 °C 2.1: p-TsOH / benzene / Heating 3.1: O3 / CH2Cl2 / -78 - 20 °C 3.2: Me2S / CH2Cl2 / 5 h / 20 °C 3.3: 5.91 g / Ph3P / CH2Cl2 / 5 h / 20 °C 4.1: 100 percent / (PhS)2; SmI2 / tetrahydrofuran / 1 h / 25 °C View Scheme