1: 1.) n-BuLi / 1.) THF, hexane, room temperature, 20 min, 2.) room temperature, 30 min 2: 88 percent / MeONa, LiAlH4 / methanol; tetrahydrofuran / 1 h / Heating 3: 99 percent / TBAF / tetrahydrofuran / 16 h / Ambient temperature 4: 1.) p-TsOH, 2.) t-BuOMe, 9-acetoxyanthracene / 1.) dioxane, H2O, 75 deg C, 4 h, 2.) irradiation, 1 h View Scheme

n-butyllithium 1.) THF, n-hexane, -78 deg C, 5 min, 2.) THF, n-hexane, -78 deg C, 2 h; Yield given. Multistep reaction;