1.1: 95 percent / CH2Cl2 / 20 °C 2.1: NaBH4; BF3*OEt2 / tetrahydrofuran / 2 h / 20 °C 2.2: 90 percent / NaOH / H2O / 1 h / Heating 3.1: 82 percent / 120 °C 4.1: t-BuLi / diethyl ether; pentane / 0.17 h / -90 °C 4.2: 79 percent / Et2AlCl / hexane / -90 - 20 °C 5.1: PCC; NaOAc; 3A molecular sieves / CH2Cl2 / 48 h / 20 °C 5.2: 58 percent / KOH / tetrahydrofuran View Scheme

1: sodium tetrahydroborate / methanol / 1 h / 0 - 20 °C 2: pyridine; phosphorus tribromide / dichloromethane / 1 h / 0 - 20 °C / |Inert atmosphere View Scheme

1: sodium tetrahydroborate / methanol / 1 h / 0 - 20 °C 2: pyridine; phosphorus tribromide / dichloromethane / 1 h / 0 - 20 °C / |Inert atmosphere 3: ammonia / ethanol; water / 4 h / 20 °C View Scheme