1: diphenyl phosphoryl azide; triethylamine / toluene / 0.17 h / 100 °C / Inert atmosphere; Microwave irradiation 2: pyridine / dichloromethane / 0.5 h / 20 °C / Inert atmosphere; Cooling with ice 3: triethylsilane; 1,3-bis-(diphenylphosphino)propane; palladium diacetate / N,N-dimethyl-formamide / 1 h / 60 °C / Inert atmosphere 4: methanol; trifluorormethanesulfonic acid; trimethyl orthoformate / nitromethane / 1 h / 100 °C / Inert atmosphere; Cooling with ice View Scheme