1: With ozone in dichloromethane ozonolysis; 2 h; 2: With triphenylphosphine in dichloromethane T=0°C; Reduction; 40 h;

1.1: 92 percent / Zn; NH4Cl / tetrahydrofuran; H2O / 1 h 2.1: 86 percent / NaH / tetrahydrofuran / 12 h / 20 °C 3.1: ozone / CH2Cl2 / 2 h 3.2: 81 percent / triphenylphosphine / CH2Cl2 / 40 h / 0 °C View Scheme

1.1: 90 percent / pyridinium chlorochromate / CH2Cl2 / 3 h / 0 °C 2.1: 92 percent / Zn; NH4Cl / tetrahydrofuran; H2O / 1 h 3.1: 86 percent / NaH / tetrahydrofuran / 12 h / 20 °C 4.1: ozone / CH2Cl2 / 2 h 4.2: 81 percent / triphenylphosphine / CH2Cl2 / 40 h / 0 °C View Scheme

1.1: 86 percent / NaH / tetrahydrofuran / 12 h / 20 °C 2.1: ozone / CH2Cl2 / 2 h 2.2: 81 percent / triphenylphosphine / CH2Cl2 / 40 h / 0 °C View Scheme