1: DMAP / CH2Cl2 / 12 h / 20 °C 2: 85 percent / p-TsOH / methanol / 12 h / 20 °C 3: 88 percent / LDA; HMPA / tetrahydrofuran / 4 h / -78 °C 4: 75 percent / trifluoroacetic acid / CH2Cl2 / 3 h / 20 °C 5: aq. NaOH / 72 h / 20 °C 6: 16 mg / triethylamine; bis(2-oxo-3-oxazolidinyl)phosphonic chloride / CH2Cl2 / 3 h / 20 °C View Scheme

1: 85 percent / p-TsOH / methanol / 12 h / 20 °C 2: 88 percent / LDA; HMPA / tetrahydrofuran / 4 h / -78 °C 3: 75 percent / trifluoroacetic acid / CH2Cl2 / 3 h / 20 °C 4: aq. NaOH / 72 h / 20 °C 5: 16 mg / triethylamine; bis(2-oxo-3-oxazolidinyl)phosphonic chloride / CH2Cl2 / 3 h / 20 °C View Scheme

1: 80 percent / tetrahydrofuran / 24 h / -20 °C 4: 76 percent / BOPCl, Et3N / CD2Cl2 / 0.33 h / 23 °C View Scheme

3: 76 percent / BOPCl, Et3N / CD2Cl2 / 0.33 h / 23 °C View Scheme

1: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 20 °C 2: N,N,N',N',N'',N''-hexamethylphosphoric triamide; lithium diisopropyl amide / tetrahydrofuran; hexane / 4 h / -78 °C 3: trifluoroacetic acid / dichloromethane / 4 - 20 °C 4: water; sodium hydroxide / 64 h / 4 °C 5: bis-(2-oxo-3-oxazolidinyl)phosphoryl chloride; triethylamine / dichloromethane / 2 h View Scheme

1.1: sodium hydride / N,N-dimethyl-formamide; mineral oil / 1 h / 0 °C 1.2: 20 °C 2.1: trifluoroacetic acid / dichloromethane; water / 20 °C 3.1: Dess-Martin periodane / dichloromethane / 0 - 20 °C 4.1: chloro-trimethyl-silane / tetrahydrofuran / 2 h / -40 °C 5.1: palladium 10 on activated carbon; hydrogen / ethanol 6.1: 4-(N,N-dimethlyamino)pyridine / pyridine / 0 - 20 °C 7.1: ammonium cerium (IV) nitrate / water; acetonitrile / 20 °C 8.1: 4-(N,N-dimethlyamino)pyridine; triethylamine / tetrahydrofuran / 20 °C / Reflux 9.1: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 20 °C 10.1: N,N,N',N',N'',N''-hexamethylphosphoric triamide; lithium diisopropyl amide / tetrahydrofuran; hexane / 4 h / -78 °C 11.1: trifluoroacetic acid / dichloromethane / 4 - 20 °C 12.1: water; sodium hydroxide / 64 h / 4 °C 13.1: bis-(2-oxo-3-oxazolidinyl)phosphoryl chloride; triethylamine / dichloromethane / 2 h View Scheme

1: trifluoroacetic acid / dichloromethane; water / 20 °C 2: Dess-Martin periodane / dichloromethane / 0 - 20 °C 3: chloro-trimethyl-silane / tetrahydrofuran / 2 h / -40 °C 4: palladium 10 on activated carbon; hydrogen / ethanol 5: 4-(N,N-dimethlyamino)pyridine / pyridine / 0 - 20 °C 6: ammonium cerium (IV) nitrate / water; acetonitrile / 20 °C 7: 4-(N,N-dimethlyamino)pyridine; triethylamine / tetrahydrofuran / 20 °C / Reflux 8: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 20 °C 9: N,N,N',N',N'',N''-hexamethylphosphoric triamide; lithium diisopropyl amide / tetrahydrofuran; hexane / 4 h / -78 °C 10: trifluoroacetic acid / dichloromethane / 4 - 20 °C 11: water; sodium hydroxide / 64 h / 4 °C 12: bis-(2-oxo-3-oxazolidinyl)phosphoryl chloride; triethylamine / dichloromethane / 2 h View Scheme

1: Dess-Martin periodane / dichloromethane / 0 - 20 °C 2: chloro-trimethyl-silane / tetrahydrofuran / 2 h / -40 °C 3: palladium 10 on activated carbon; hydrogen / ethanol 4: 4-(N,N-dimethlyamino)pyridine / pyridine / 0 - 20 °C 5: ammonium cerium (IV) nitrate / water; acetonitrile / 20 °C 6: 4-(N,N-dimethlyamino)pyridine; triethylamine / tetrahydrofuran / 20 °C / Reflux 7: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 20 °C 8: N,N,N',N',N'',N''-hexamethylphosphoric triamide; lithium diisopropyl amide / tetrahydrofuran; hexane / 4 h / -78 °C 9: trifluoroacetic acid / dichloromethane / 4 - 20 °C 10: water; sodium hydroxide / 64 h / 4 °C 11: bis-(2-oxo-3-oxazolidinyl)phosphoryl chloride; triethylamine / dichloromethane / 2 h View Scheme

1: chloro-trimethyl-silane / tetrahydrofuran / 2 h / -40 °C 2: palladium 10 on activated carbon; hydrogen / ethanol 3: 4-(N,N-dimethlyamino)pyridine / pyridine / 0 - 20 °C 4: ammonium cerium (IV) nitrate / water; acetonitrile / 20 °C 5: 4-(N,N-dimethlyamino)pyridine; triethylamine / tetrahydrofuran / 20 °C / Reflux 6: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 20 °C 7: N,N,N',N',N'',N''-hexamethylphosphoric triamide; lithium diisopropyl amide / tetrahydrofuran; hexane / 4 h / -78 °C 8: trifluoroacetic acid / dichloromethane / 4 - 20 °C 9: water; sodium hydroxide / 64 h / 4 °C 10: bis-(2-oxo-3-oxazolidinyl)phosphoryl chloride; triethylamine / dichloromethane / 2 h View Scheme

1: palladium 10 on activated carbon; hydrogen / ethanol 2: 4-(N,N-dimethlyamino)pyridine / pyridine / 0 - 20 °C 3: ammonium cerium (IV) nitrate / water; acetonitrile / 20 °C 4: 4-(N,N-dimethlyamino)pyridine; triethylamine / tetrahydrofuran / 20 °C / Reflux 5: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 20 °C 6: N,N,N',N',N'',N''-hexamethylphosphoric triamide; lithium diisopropyl amide / tetrahydrofuran; hexane / 4 h / -78 °C 7: trifluoroacetic acid / dichloromethane / 4 - 20 °C 8: water; sodium hydroxide / 64 h / 4 °C 9: bis-(2-oxo-3-oxazolidinyl)phosphoryl chloride; triethylamine / dichloromethane / 2 h View Scheme