1.1: magnesium / diethyl ether 1.2: 0.25 h / -20 °C 1.3: 2 h / 20 °C 2.1: lithium aluminium tetrahydride / tetrahydrofuran / 0.17 h / 20 °C / |Inert atmosphere 3.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 2 h / 20 °C 4.1: di-isopropyl azodicarboxylate; triphenylphosphine / 1,4-dioxane / 2 h / 100 °C 5.1: zinc dibromide / dichloromethane / 12 h View Scheme