1: 73 percent / phosphoric acid, BF3*Et2O / CH2Cl2 / 1.) -78 deg C, 2 h, 2.) 0 deg C, 24 h 2: 65 percent / H2O / 70 h / 25 °C / bakers' yeast (Red Star) 3: 86 percent / pyridine / 16 h / 25 °C 4: p-toluenesulfonic acid monohydrate / benzene / 1.5 h / Heating 5: diethyl ether 6: 66 percent / CaCO3, CH3I / acetone; H2O / 7 h / 65 °C 7: 1.) n-BuLi, 2.) HMPA / 1.) THF, hexane, -78 deg C, 15 min, 2a.) THF, hexane, -78 deg C, 40 min, 2b.) -20 deg C, 30 min 8: 48 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 5 h / 25 °C 9: 68 percent / K2CO3 / methanol; H2O / 12 h / Ambient temperature View Scheme