1.1: 87 percent / NaBH4 / CeCl3 / methanol 2.1: 83 percent / (-)-DIPT; cumene hydroperoxide; MS / Ti(OPr-i)4 / CH2Cl2 / -20 °C 3.1: DBU / CH2Cl2 / 1.5 h / 0 °C 3.2: Et2AlCl / CH2Cl2 / 0 - 20 °C 4.1: 1H-tetrazole / CH2Cl2; acetonitrile 4.2: t-BuOOH / 20 °C 5.1: aq. HCl / tetrahydrofuran / 20 °C View Scheme

1.1: 87 percent / NaBH4 / CeCl3 / methanol 2.1: 83 percent / (+)-DIPT; cumene hydroperoxide; MS / Ti(OPr-i)4 / CH2Cl2 / -20 °C 3.1: DBU / CH2Cl2 / 1.5 h / 0 °C 3.2: 74 percent / Et2AlCl / CH2Cl2 / 0 - 20 °C 4.1: 1H-tetrazole / CH2Cl2; acetonitrile / 6 h 4.2: 78 percent / t-BuOOH / 20 °C 5.1: 81 percent / aq. HCl / tetrahydrofuran / 20 °C View Scheme