1: 1.) n-BuLi, 2.) HMPA / 1.) THF, hexane, -100 deg C, 2 min, 2.) THF, hexane, from -100 deg C to RT 2: 61 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 15 h / Ambient temperature 3: potassium carbonate / methanol; H2O / 7.5 h / Ambient temperature 4: AcOH / H2O View Scheme

1: 30 percent / LiHMDS / tetrahydrofuran; hexamethylphosphoric acid triamide 2: 70 percent / (nBu)4NF / tetrahydrofuran / 0 - 25 °C 3: 70 percent / K2CO3 / methanol; H2O View Scheme