1: triethylamine / ethyl acetate / 4 h / 0 - 3 °C 2: sodium azide; ammonium chloride / methanol / 6.5 h / 10 - 20 °C 3: toluene / 1 h / 20 °C 4: toluene / 7 h / |Reflux 5: boron trifluoride diethyl etherate / 17 h / 0 - 20 °C 6: sulfuric acid / ethanol / 16 h / 78 °C 7: sodium carbonate / 0.5 h / 20 °C / pH 6.5 - 7 8: sodium azide / water; ethanol / 24 h / |Reflux 9: triphenylphosphine; acetic acid / water; tetrahydrofuran / 16 h / 45 °C View Scheme

1.1: thionyl chloride / 0.5 h / 20 °C 1.2: 0 - 20 °C 2.1: potassium carbonate / ethanol / 20 h / 20 °C 3.1: triethylamine / dichloromethane / 1 h / 0 °C 4.1: trifluoroacetic acid; water / 8 h / 20 °C 5.1: sodium azide; acetic acid / dimethyl sulfoxide / 2 h / 85 °C 6.1: 4-(N,N-dimethlyamino)pyridine; triethylamine / dichloromethane / 5 h / 20 °C 7.1: diisobutylaluminium hydride / dichloromethane; hexane / 1 h / -10 °C 8.1: 4-(N,N-dimethlyamino)pyridine; triethylamine / ethyl acetate / 1 h / 0 °C 9.1: water; ruthenium trichloride; sodium periodate / acetonitrile / 4 h / 20 °C 10.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 5 h / 20 °C 11.1: 4-(N,N-dimethlyamino)pyridine; triethylamine / tetrahydrofuran / 1 h / 0 °C 12.1: ammonium hydroxide / methanol / 25 h / |Reflux 13.1: palladium 10 on activated carbon; hydrogen / methanol; water / 24 h / 20 °C View Scheme

1.1: orthoformic acid triethyl ester 2.1: 4-(N,N-dimethlyamino)pyridine; N-ethyl-N,N-diisopropylamine / dichloromethane / 0 - 40 °C 3.1: triethylsilane; titanium tetrachloride / dichloromethane / -78 - -10 °C 4.1: hydrogen azide; triphenylphosphine; diethylazodicarboxylate / tetrahydrofuran; benzene / 10 - 20 °C 5.1: 2,6-dimethylpyridine / chloroform / 6 h / 20 - 55 °C 6.1: zirconium tetrachloride; isopropyl alcohol / 4 h / 50 °C 7.1: hydrogen azide; triphenylphosphine; diethylazodicarboxylate / tetrahydrofuran; benzene / 10 - 20 °C 8.1: hydrogen / ethanol 8.2: 50 °C View Scheme

1: triethylamine / ethyl acetate / 4 h / 0 - 3 °C 2: sodium azide; ammonium chloride / methanol / 6.5 h / 10 - 20 °C 3: toluene / 1 h / 20 °C 4: toluene / 7 h / |Reflux 5: boron trifluoride diethyl etherate / 17 h / 0 - 20 °C 6: sulfuric acid / ethanol / 16 h / 78 °C 7: sodium carbonate / 0.5 h / 20 °C / pH 6.5 - 7 8: sodium azide / water; ethanol / 24 h / |Reflux 9: 5 Pd/C; hydrogen / ethanol / 3 h / 24 °C View Scheme

1: orthoformic acid triethyl ester 2: 4-(N,N-dimethlyamino)pyridine; N-ethyl-N,N-diisopropylamine / dichloromethane / 0 - 40 °C 3: triethylsilane; titanium tetrachloride / dichloromethane / -78 - -10 °C 4: hydrogen azide; triphenylphosphine; diethylazodicarboxylate / tetrahydrofuran; benzene / 10 - 20 °C 5: 2,6-dimethylpyridine / chloroform / 6 h / 20 - 55 °C 6: zirconium tetrachloride; isopropyl alcohol / 4 h / 50 °C 7: hydrogen azide; triphenylphosphine; diethylazodicarboxylate / tetrahydrofuran; benzene / 10 - 20 °C View Scheme

1: triethylamine / ethyl acetate / 4 h / 0 - 3 °C 2: sodium azide; ammonium chloride / methanol / 6.5 h / 10 - 20 °C 3: triphenylphosphine / tetrahydrofuran 4: triethylamine / water 5: water View Scheme