1.1: sodium hydride / tetrahydrofuran / 0.25 h / 0 °C / |Inert atmosphere 1.2: 5 h / 20 °C / |Reflux; |Inert atmosphere 2.1: copper(I) bromide dimethylsulfide complex; 1,8-diazabicyclo[5.4.0]undec-7-ene; potassium iodide; caesium carbonate / 1,2-dichloro-ethane / 5 h / 135 °C / |Schlenk technique View Scheme