1.1: cesium hydroxide monohydrate / N,N-dimethyl-formamide / 0.5 h / 0 °C / |Inert atmosphere 1.2: 5 h / 0 - 20 °C / |Inert atmosphere 2.1: tetrahydrofuran; hexane / 4 h / -78 - 20 °C / |Inert atmosphere View Scheme

lithium chloride in N,N-dimethyl-formamide 1 h; Inert atmosphereReflux;