1.1: 95 percent / imidazole / tetrahydrofuran / 1.5 h / 0 °C 2.1: OsO4; NMO*H2O / tetrahydrofuran; H2O / 0 - 23 °C 2.2: 71 percent / Pb(OAc)4 / benzene / 0 - 23 °C 3.1: 91 percent / AcOH / tetrahydrofuran; H2O / 0 - 23 °C 4.1: 28 percent / Grela's catalyst / 1,2-dichloro-ethane / 10 h / 23 °C View Scheme