1.1: 2,6-dimethylpyridine / chloroform / 6 h / 20 - 55 °C 2.1: zirconium tetrachloride; isopropyl alcohol / 4 h / 50 °C 3.1: hydrogen azide; triphenylphosphine; diethylazodicarboxylate / tetrahydrofuran; benzene / 10 - 20 °C 4.1: hydrogen / ethanol 4.2: 50 °C View Scheme

1: 2,6-dimethylpyridine / chloroform / 6 h / 20 - 55 °C 2: zirconium tetrachloride; isopropyl alcohol / 4 h / 50 °C 3: hydrogen azide; triphenylphosphine; diethylazodicarboxylate / tetrahydrofuran; benzene / 10 - 20 °C View Scheme