1: lithium aluminium tetrahydride / tetrahydrofuran / 0.17 h / 20 °C / |Inert atmosphere 2: tetrabutyl ammonium fluoride / tetrahydrofuran / 2 h / 20 °C 3: di-isopropyl azodicarboxylate; triphenylphosphine / 1,4-dioxane / 2 h / 100 °C 4: zinc dibromide / dichloromethane / 12 h View Scheme