1: 86 percent / Ph3P / CCl4 / 2 h / 75 - 80 °C 2: 83 percent / xylene / 10 h / Heating 3: 1.) n-BuLi / 1.) benzene, 30 min 2.) benzene, 4 h 4: 40percent aq. HF / acetonitrile / 4 h / Ambient temperature View Scheme

1: PDC / dichloromethane / 20 h / 20 °C 2: sodium hydride / tetrahydrofuran / 18 h / 0 - 20 °C 3: tetrabutyl ammonium fluoride / tetrahydrofuran / 1 h / 20 °C View Scheme

1.1: 61 percent / p-TsCl; Et3N; 4-dimethylaminopyridine / CH2Cl2 / 12 h / 20 °C 2.1: 86.1 percent / NaI / 6 h / 135 °C 3.1: NaH / tetrahydrofuran / 2 h / -55 - 0 °C 3.2: 50.8 percent / tetrahydrofuran / 24 h / -55 - 0 °C 4.1: 79 percent / hydrochloric acid / ethanol / 26 h / 20 °C View Scheme

1: 86 percent / Ph3P / CCl4 / 2 h / 75 - 80 °C 2: 83 percent / xylene / 10 h / Heating 3: 1.) n-BuLi / 1.) benzene, 30 min 2.) benzene, 4 h 4: 40percent aq. HF / acetonitrile / 4 h / Ambient temperature View Scheme

With  lithium aluminium tetrahydride in  diethyl ether 2 h;  Ambient temperature;   

Multi-step reaction with 2 steps 1: 87 percent / PPh3, CCl4 / 2 h / 110 °C2: 86 percent / 5 h / 100 °C  

Multi-step reaction with 3 steps 1: 86 percent / Ph3P / CCl4 / 2 h / 75 - 80 °C2: 83 percent / xylene / 10 h / Heating3: 1.) n-BuLi / 1.) benzene, 30 min 2.) benzene, 4 h