potassium hydroxide; hydrazine hydrate in water; ethylene glycol 120 degC, 1 h then 190-195 degC, 3 h;

1: 82 percent / hydrazine hydrate, KOH / H2O; ethane-1,2-diol / 120 degC, 1 h then 190-195 degC, 3 h 2: 91 percent / diisopropylamine, n-butyllithium, hexamethylphosphoramide / tetrahydrofuran; hexane / 2 h / -78 °C 3: sodium metaperiodate / methanol; H2O / 18 h / Ambient temperature 4: CaCO3 / toluene / 1 h / Heating View Scheme