1: LiHMDS / tetrahydrofuran; hexamethylphosphoric acid triamide / -78 °C 2: -78 - -45 °C 3: 80 percent / (nBu)4NF / tetrahydrofuran / 0 - 25 °C 4: 70 percent / LiOH / 1,2-dimethoxy-ethane; H2O / Ambient temperature View Scheme