1.1: 1.74 g / pyridinium chlorochromate; molecular sieves 4 Angstroem; Celite / CH2Cl2 / 1.5 h / 20 °C 2.1: pyridinium p-toluenesulfonate; MgSO4 / diethyl ether / 18 h / 20 °C 3.1: 52 percent / BF3*Et2O / diethyl ether / 3 h / -78 - -50 °C 4.1: Mg; 1,2-dibromoethane / tetrahydrofuran / 3 h / Heating 4.2: CuBr*Me2S; trimethylsilylchloride / tetrahydrofuran / 1.67 h / -78 °C 4.3: 6.9 g / tetrahydrofuran / 1 h / -78 °C 5.1: diisobutylaluminum hydride / hexane; tetrahydrofuran / 0.75 h / -78 °C 6.1: pyridinium p-toluenesulfonate / 1 h / 20 °C 7.1: 4.4 g / BF3*Et2O / CH2Cl2 / 0.5 h / -78 °C 8.1: methanol; pyridinium p-toluenesulfonate / 18 h / Heating 9.1: 1.92 g / triethylamine / CH2Cl2 / 1 h / 20 °C 10.1: hydrochloric acid / 42 h / 60 °C View Scheme