1: 81 percent / (COCl)2, DMSO, Et3N / CH2Cl2 / 1 h / Ambient temperature 2: 1.) t-BuOK / 1.) THF, -70 deg C, 15 min, 2.) -78 deg C, 30 min; -78 deg C -> room temperature 3: 80 percent / p-TsOH / acetone; H2O / 48 h / Heating 4: 1.) t-BuOK / 1.) THF, room temperature, 30 min, 2.) 1 h 5: 48 percent / SeO2, t-BuOOH / 2,2,4-trimethyl-pentane / 1.) 0 deg C, 2 h, 2.) room temperature, 4 h 6: 94 percent / imidazole / dimethylformamide / 4 h / Ambient temperature 7: 1.) n-BuLi / 1.) THF, hexane, room temperature, 20 min, 2.) room temperature, 30 min 8: 88 percent / MeONa, LiAlH4 / methanol; tetrahydrofuran / 1 h / Heating 9: 99 percent / TBAF / tetrahydrofuran / 16 h / Ambient temperature 10: 1.) p-TsOH, 2.) t-BuOMe, 9-acetoxyanthracene / 1.) dioxane, H2O, 75 deg C, 4 h, 2.) irradiation, 1 h View Scheme