acetic acid in tetrahydrofuran 4 h; Ambient temperature;

1: 78 percent / diethyl ether / 1 h / Ambient temperature 2: 61 percent / pyridinium p-toluenesulfonate / ethanol / 4 h / 60 - 70 °C 3: 88 percent / pyridinium chlorochromate (PCC), NaOAc / CH2Cl2 / 8 h / Ambient temperature 4: 84 percent / dimethylformamide / 80 °C 5: 1) lithium diisopropylamide / 1) THF, -60 deg C, 20 min, 2) -60 to -5 deg C 6: 1) lithium diisopropylamide / 1) THF, -70 deg C, 15 min, 2) -70 deg C, 1 h 7: 30 percent aq. acetic acid / tetrahydrofuran / 3 h / Ambient temperature 8: 71 percent / triethylamine, 4-dimethylaminopyridine / 48 h / Ambient temperature 9: 40 percent / triethylamine, 4-dimethylaminopyridine / 7 h / ice-NaCl bath 10: 70 percent / aq. acetic acid / tetrahydrofuran / 4 h / Ambient temperature View Scheme

1: 84 percent / dimethylformamide / 80 °C 2: 1) lithium diisopropylamide / 1) THF, -60 deg C, 20 min, 2) -60 to -5 deg C 3: 1) lithium diisopropylamide / 1) THF, -70 deg C, 15 min, 2) -70 deg C, 1 h 4: 30 percent aq. acetic acid / tetrahydrofuran / 3 h / Ambient temperature 5: 71 percent / triethylamine, 4-dimethylaminopyridine / 48 h / Ambient temperature 6: 40 percent / triethylamine, 4-dimethylaminopyridine / 7 h / ice-NaCl bath 7: 70 percent / aq. acetic acid / tetrahydrofuran / 4 h / Ambient temperature View Scheme

1: 94 percent / p-toluenesulfonic acid monohydrate / CH2Cl2 / 1.5 h / ice-bath 2: 78 percent / diethyl ether / 1 h / Ambient temperature 3: 61 percent / pyridinium p-toluenesulfonate / ethanol / 4 h / 60 - 70 °C 4: 88 percent / pyridinium chlorochromate (PCC), NaOAc / CH2Cl2 / 8 h / Ambient temperature 5: 84 percent / dimethylformamide / 80 °C 6: 1) lithium diisopropylamide / 1) THF, -60 deg C, 20 min, 2) -60 to -5 deg C 7: 1) lithium diisopropylamide / 1) THF, -70 deg C, 15 min, 2) -70 deg C, 1 h 8: 30 percent aq. acetic acid / tetrahydrofuran / 3 h / Ambient temperature 9: 71 percent / triethylamine, 4-dimethylaminopyridine / 48 h / Ambient temperature 10: 40 percent / triethylamine, 4-dimethylaminopyridine / 7 h / ice-NaCl bath 11: 70 percent / aq. acetic acid / tetrahydrofuran / 4 h / Ambient temperature View Scheme

1: 71 percent / triethylamine, 4-dimethylaminopyridine / 48 h / Ambient temperature 2: 40 percent / triethylamine, 4-dimethylaminopyridine / 7 h / ice-NaCl bath 3: 70 percent / aq. acetic acid / tetrahydrofuran / 4 h / Ambient temperature View Scheme

1: 30 percent aq. acetic acid / tetrahydrofuran / 3 h / Ambient temperature 2: 71 percent / triethylamine, 4-dimethylaminopyridine / 48 h / Ambient temperature 3: 40 percent / triethylamine, 4-dimethylaminopyridine / 7 h / ice-NaCl bath 4: 70 percent / aq. acetic acid / tetrahydrofuran / 4 h / Ambient temperature View Scheme