1.1: silica gel / 72 h / 20 °C 1.2: 66 percent / aq. ammonium cerium nitrate / diethyl ether / 1 h / 20 °C 2.1: 80 percent / OsO4; pyridine / 24 h 3.1: 95 percent / H2O2 / tetrahydrofuran / 16 h 4.1: 4 Angstroem molecular sieves 5.1: NaH; pyridine / 1 h / 20 °C View Scheme