1: 84.4 percent / NaBH4, NaH, 2-propanol / dioxane / 1.) 70 deg C, 2.) reflux, 1 h 2: 94 percent / NaIO4 / H2O; methanol / 20 h / Ambient temperature 3: LDA / tetrahydrofuran / 1.) -78 deg C, 30 min, 2.) 30 min, ice bath 4: Al-Hg / tetrahydrofuran; H2O / 6 h / Heating View Scheme

1: 84.4 percent / NaBH4, NaH, 2-propanol / dioxane / 1.) 70 deg C, 2.) reflux, 1 h 2: 87.6 percent / LDA / tetrahydrofuran / 1.) 1 h, -78 deg C, 2.) 2 h, ice bath, 3.) 0.5 h, r.t. 3: 94 percent / NaIO4 / H2O; methanol / 20 h / Ambient temperature 4: LDA / tetrahydrofuran / 1.) -78 deg C, 30 min, 2.) 30 min, ice bath 5: xylene / 2 h / 100 °C View Scheme

sodium tetrahydroborate; sodium hydride; isopropyl alcohol in 1,4-dioxane 1.) 70 deg C, 2.) reflux, 1 h;