1.1: triphenylphosphine; diethylazodicarboxylate / tetrahydrofuran / 0.5 h / -20 °C / Inert atmosphere 1.2: 10 h / -25 - -15 °C 2.1: water; triphenylphosphine / 15 h / 65 °C 3.1: triethylamine / dichloromethane / 1 h / 20 °C 4.1: sodium hydride / N,N-dimethyl-formamide / 0.08 h / 20 °C 4.2: 1 h / 20 °C 5.1: water; sodium hydroxide / isopropyl alcohol / 24 h / 100 °C View Scheme