1.1: LiEt3BH / tetrahydrofuran / 8 h / 40 °C 1.2: 37 percent / CH2Cl2 / 2 h / 40 °C 2.1: CH2Cl2 / 8 h / 20 °C 2.2: dimethyldioxirane / acetone / 1 h / 20 °C 2.3: DBU / CH2Cl2 / 2 h / 40 °C 3.1: NaBH4 / ethanol 3.2: ethanol / 4 h / 80 °C 4.1: aq. NaIO4 / tetrahydrofuran / 1 h 5.1: chloroform / 2 h / 70 °C 6.1: 50 percent / (triphenylsiloxy)trioxorhenium(VII); TsOH / benzene / 1 h / 80 °C View Scheme