1: tetrahydrofuran / -78 °C 2: pyridine 3: 1.) LDA, TBSCl, HMPA, 2.) Bu4NF / 1.) THF, -78 deg C, 2.) reflux, 1.5 h 5: 95 percent / p-toluenesulfonic acid / 0 °C 6: i-Pr2NEt / CH2Cl2 7: lithium aluminum hydride / diethyl ether 8: CH2Cl2 9: 1.) butyllithium, 2.) Hg(OAc)2 / 1.) heptane, 2.) THF, water 10: CrO3-2Pyr / CH2Cl2 / 0 °C 11: tetrahydrofuran / -78 °C 12: DDQ / dioxane / 10 h 13: Bu4NF / tetrahydrofuran 14: CrO3-2Pyr / CH2Cl2 / 0 °C 15: 2.) camphorsulphonic acid / 1.) THF, -100 deg C, 2.) methylene chloride, -15 deg C, 10 h 16: 1.) Cr2(OAc)4-2H2O, 2.) potassium carbonate, methanol / 1.) EtOH, 2.) water View Scheme