1: 89 percent / CeCl3, n-BuLi / tetrahydrofuran / 2 h / -78 °C 2: 71 percent / NaOEt / ethanol / 0.83 h / Ambient temperature 3: 85 percent / KOH / ethanol; H2O / 1 h / Heating 4: 99 percent / (trimethylsilyl)ethoxyacetylene 5: 66 percent / NaH / tetrahydrofuran / 2 h / Ambient temperature 6: 88 percent / HgO(yellow), 20percent H2SO4 / tetrahydrofuran / 5 h / Heating View Scheme