1: trifluoroacetic acid / dichloromethane / 1 h / Inert atmosphere 2: pyridine / tetrahydrofuran / 18 h / 20 °C / Inert atmosphere 3: trifluoroacetic acid; trifluoroacetic anhydride / dichloromethane / 30 h / 20 °C / Inert atmosphere 4: bis-triphenylphosphine-palladium(II) chloride; cesium fluoride / N,N-dimethyl-formamide / 14 h / 100 °C / Inert atmosphere; Sealed vessel View Scheme