1: 42 h / Ambient temperature 2: HCl(g) / acetonitrile / 20 h / -42 - 20 °C 3: 1,8-diazabicyclo<5.4.0>undec-7-ene / benzene / Ambient temperature 4: BF3*Et2O / benzene; methanol / 18 h / Ambient temperature 5: 50percent aq. AcOH / ethyl acetate / Ambient temperature 6: 87 percent / diphenylphosphoryl azide, 1,8-diazabicyclo<5.4.0>undec-7-ene / 23 h / Ambient temperature View Scheme

1: BF3*Et2O / benzene; methanol / 18 h / Ambient temperature 2: 50percent aq. AcOH / ethyl acetate / Ambient temperature 3: 87 percent / diphenylphosphoryl azide, 1,8-diazabicyclo<5.4.0>undec-7-ene / 23 h / Ambient temperature View Scheme

1.1: Dowex-50 (H+) / 40 - 45 °C 2.1: pyridine / 20 °C / Cooling with ice 3.1: trimethylsilyl trifluoromethanesulfonate / ethyl acetate / 3 h / 30 - 52 °C / Inert atmosphere 4.1: trimethylsilylazide / tert-butyl alcohol / Inert atmosphere; Reflux 4.2: 1 h View Scheme

1: Amberlite IR120 (H+) 2: pyridine 3: trimethylsilyl trifluoromethanesulfonate / ethyl acetate / 3 h / 50 °C 4: trimethylsilylazide / tert-butyl alcohol / 9 h / Reflux View Scheme

1: 1,8-diazabicyclo<5.4.0>undec-7-ene / benzene / Ambient temperature 2: BF3*Et2O / benzene; methanol / 18 h / Ambient temperature 3: 50percent aq. AcOH / ethyl acetate / Ambient temperature 4: 87 percent / diphenylphosphoryl azide, 1,8-diazabicyclo<5.4.0>undec-7-ene / 23 h / Ambient temperature View Scheme

1: osmium(VIII) oxide; 4-methylmorpholine N-oxide / water; acetone; tert-butyl alcohol / 2.5 h / 45 °C / Inert atmosphere 2: sodium periodate / water; acetone; tert-butyl alcohol / 2 h / 20 °C / Inert atmosphere 3: lithium hexamethyldisilazane / tetrahydrofuran / 1 h / -20 °C / Inert atmosphere 4: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 0.33 h / 0 °C / Inert atmosphere 5: boron trifluoride diethyl etherate / acetonitrile / 0.5 h / 0 °C / Inert atmosphere 6: 30 Pd/C; hydrogen / tetrahydrofuran; methanol / 3 h / 20 °C / 760.05 Torr / Inert atmosphere 7: pyridine; 4-(N,N-dimethlyamino)pyridine / 5.5 h / 20 °C / Inert atmosphere 8: triphenylphosphine hydrobromide / acetonitrile / 5 h / 0 - 55 °C / Inert atmosphere 9: copper(I) bromide / dichloromethane / 3 h / Reflux; Inert atmosphere 10: sulfuric acid; acetic acid / 12 h / 0 - 20 °C / Inert atmosphere 11: trimethylsilylazide / tert-butyl alcohol / 10 h / Reflux; Inert atmosphere View Scheme

1: lithium hexamethyldisilazane / tetrahydrofuran / 1 h / -20 °C / Inert atmosphere 2: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 0.33 h / 0 °C / Inert atmosphere 3: boron trifluoride diethyl etherate / acetonitrile / 0.5 h / 0 °C / Inert atmosphere 4: 30 Pd/C; hydrogen / tetrahydrofuran; methanol / 3 h / 20 °C / 760.05 Torr / Inert atmosphere 5: pyridine; 4-(N,N-dimethlyamino)pyridine / 5.5 h / 20 °C / Inert atmosphere 6: triphenylphosphine hydrobromide / acetonitrile / 5 h / 0 - 55 °C / Inert atmosphere 7: copper(I) bromide / dichloromethane / 3 h / Reflux; Inert atmosphere 8: sulfuric acid; acetic acid / 12 h / 0 - 20 °C / Inert atmosphere 9: trimethylsilylazide / tert-butyl alcohol / 10 h / Reflux; Inert atmosphere View Scheme

1: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 0.33 h / 0 °C / Inert atmosphere 2: boron trifluoride diethyl etherate / acetonitrile / 0.5 h / 0 °C / Inert atmosphere 3: 30 Pd/C; hydrogen / tetrahydrofuran; methanol / 3 h / 20 °C / 760.05 Torr / Inert atmosphere 4: pyridine; 4-(N,N-dimethlyamino)pyridine / 5.5 h / 20 °C / Inert atmosphere 5: triphenylphosphine hydrobromide / acetonitrile / 5 h / 0 - 55 °C / Inert atmosphere 6: copper(I) bromide / dichloromethane / 3 h / Reflux; Inert atmosphere 7: sulfuric acid; acetic acid / 12 h / 0 - 20 °C / Inert atmosphere 8: trimethylsilylazide / tert-butyl alcohol / 10 h / Reflux; Inert atmosphere View Scheme

1: sulfuric acid; acetic acid / 12 h / 0 - 20 °C / Inert atmosphere 2: trimethylsilylazide / tert-butyl alcohol / 10 h / Reflux; Inert atmosphere View Scheme

1.1: hydrogenchloride; methanol; zinc / 1 h / 0 °C / Inert atmosphere 2.1: triethylamine / dichloromethane / 10 h / 0 - 20 °C / Inert atmosphere 2.2: 0.25 h / Inert atmosphere 3.1: boron trifluoride diethyl etherate / acetone / 1 h / 0 °C / Inert atmosphere 4.1: water; 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane / 12 h / 0 - 20 °C / Inert atmosphere 5.1: titanium(IV) isopropylate; tert.-butylhydroperoxide; D-(-)-tartaric acid diethyl ester / decane; dichloromethane / 69 h / -20 °C / Inert atmosphere 6.1: tetrabutyl ammonium fluoride; water / acetonitrile / 91 h / 50 °C / Inert atmosphere 7.1: sodium hydride / N,N-dimethyl-formamide; mineral oil / 3 h / 0 °C / Inert atmosphere 8.1: hydrogenchloride / 1,4-dioxane; dichloromethane / 3 h / 0 °C / Inert atmosphere 9.1: triethylamine / ethyl acetate / 0.17 h / 0 °C / Inert atmosphere 10.1: 2,6-dimethylpyridine / dichloromethane / 0.58 h / -78 - 20 °C / Inert atmosphere 11.1: osmium(VIII) oxide; 4-methylmorpholine N-oxide / water; acetone; tert-butyl alcohol / 2.5 h / 45 °C / Inert atmosphere 12.1: sodium periodate / water; acetone; tert-butyl alcohol / 2 h / 20 °C / Inert atmosphere 13.1: lithium hexamethyldisilazane / tetrahydrofuran / 1 h / -20 °C / Inert atmosphere 14.1: tetrabutyl ammonium fluoride; acetic acid / tetrahydrofuran / 0.33 h / 0 °C / Inert atmosphere 15.1: boron trifluoride diethyl etherate / acetonitrile / 0.5 h / 0 °C / Inert atmosphere 16.1: 30 Pd/C; hydrogen / tetrahydrofuran; methanol / 3 h / 20 °C / 760.05 Torr / Inert atmosphere 17.1: pyridine; 4-(N,N-dimethlyamino)pyridine / 5.5 h / 20 °C / Inert atmosphere 18.1: triphenylphosphine hydrobromide / acetonitrile / 5 h / 0 - 55 °C / Inert atmosphere 19.1: copper(I) bromide / dichloromethane / 3 h / Reflux; Inert atmosphere 20.1: sulfuric acid; acetic acid / 12 h / 0 - 20 °C / Inert atmosphere 21.1: trimethylsilylazide / tert-butyl alcohol / 10 h / Reflux; Inert atmosphere View Scheme