1: 1.) HC(OEt)3 / 1.) AcOH / 1.) EtOAc 2.) 250 deg C 2: 82 percent / xylene / 18 h / Heating 3: 81 percent / I2 / tetrahydrofuran; H2O / 0 °C 4: 86 percent / NaBH4 / ethanol 5: 93 percent / imidazole / dimethylformamide 6: 94 percent / xylene / 7 h / Heating 7: 81 percent / tetrahydrofuran / -78 °C 8: 85 percent / N-Methylmorpholine-N-oxide, OsO4 9: 93 percent / anhydr. CuSO4, TsOH 10: 75 percent / tetrahydrofuran / 24 h / Ambient temperature 11: 87 percent / Bu4NF / tetrahydrofuran / 4 h / Ambient temperature 12: 80 percent / PCC,molecular sieve / CH2Cl2 / 1 h / Ambient temperature 13: 1.) n-BuLi / 2.) THF, -40 to -30 deg C, 2 h and 0 deg C, 30 min. 14: 50percent aq. AcOH / 72 h / Ambient temperature View Scheme

orthoformic acid triethyl ester; acetic acid 1.) EtOAc 2.) 250 deg C; Yield given. Multistep reaction;

1: acetic acid / ethyl acetate 2: 200 °C 3: 60 percent / xylene / Heating View Scheme

1: 1.) HC(OEt)3 / 1.) AcOH / 1.) EtOAc 2.) 250 deg C 2: 82 percent / xylene / 18 h / Heating 3: 81 percent / I2 / tetrahydrofuran; H2O / 0 °C 4: 86 percent / NaBH4 / ethanol View Scheme

1: 1.) HC(OEt)3 / 1.) AcOH / 1.) EtOAc 2.) 250 deg C 2: 82 percent / xylene / 18 h / Heating 3: 81 percent / I2 / tetrahydrofuran; H2O / 0 °C 4: 86 percent / NaBH4 / ethanol 5: 93 percent / imidazole / dimethylformamide View Scheme

1: 1.) HC(OEt)3 / 1.) AcOH / 1.) EtOAc 2.) 250 deg C 2: 82 percent / xylene / 18 h / Heating 3: 81 percent / I2 / tetrahydrofuran; H2O / 0 °C 4: 86 percent / NaBH4 / ethanol 5: 93 percent / imidazole / dimethylformamide 6: 94 percent / xylene / 7 h / Heating 7: 81 percent / tetrahydrofuran / -78 °C 8: 85 percent / N-Methylmorpholine-N-oxide, OsO4 9: 93 percent / anhydr. CuSO4, TsOH 10: 75 percent / tetrahydrofuran / 24 h / Ambient temperature 11: 87 percent / Bu4NF / tetrahydrofuran / 4 h / Ambient temperature 12: 80 percent / PCC,molecular sieve / CH2Cl2 / 1 h / Ambient temperature 13: 1.) n-BuLi / 2.) THF, -40 to -30 deg C, 2 h and 0 deg C, 30 min. 14: 50percent aq. AcOH / 72 h / Ambient temperature View Scheme