sulfuric acid

1: 90 percent / Et3N, DMAP / CH2Cl2 / 18 h / Ambient temperature 2: imidazole / dimethylformamide / 24 h / Ambient temperature 3: NaI, NaHCO3 / acetone / 24 h / Heating 4: iPr2NH2, 2.5M n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C, 30 min, 2.) -50 deg C, 10 min, then 0 deg C, 45 min 5: AcOH, 1M HCl / tetrahydrofuran; H2O / 48 h / 50 - 55 °C View Scheme