1: 98 percent / conc. H2SO4 / 5 h / Heating 2: 89 percent / nBuLi; hexamethyldisilazane / tetrahydrofuran; hexane / 0.5 h / -78 °C 3: 79 percent / BrCCl3; DBU / CH2Cl2 / 12 h / 20 °C 4: 87 percent / NaOH / methanol; H2O / 6 h / Heating View Scheme