1: p-toluenesulfonic acid / 48 h / Ambient temperature 2: 4-(dimethylamino)pyridine, imdazole / dimethylformamide / 72 h / Ambient temperature 3: diisobutylaluminum hydride / CH2Cl2 / 29 h / -78 °C 4: 1) 1.6M n-BuLi / 1) Et2O, 0 deg C, 1.5 h, 2) Et2O, r.t., 24 h 5: 54 percent / <Ce(NH4)2(NO3)6> / acetonitrile; CHCl3; H2O / 1 h / 0 °C 6: 29 percent / AgO, 6 N HNO3 / dioxane / 0.75 h / Ambient temperature 7: 51 percent / (n-C4H9)4NF*3H2O / tetrahydrofuran / 40 h / Ambient temperature View Scheme