1: 82 percent / AcOH, LiCl / hexamethylphosphoric acid triamide / 17.5 h / 110 °C 2: 100 percent / triethylorthoformate / p-toluenesulfonic acid / 25 h / Ambient temperature 3: tetrahydrofuran / 5 h / -78 - 25 °C 4: K2CO3, 18-crown-6 / tetrahydrofuran / 21 h / 40 °C 5: 95 percent / hexane / 68 h / 25 °C / Irradiation 6: NaH / diethyl ether / 0 - 25 °C View Scheme