1: anhydrous iron chloride / ethylene glycol dimethyl ether / -15 - 20 °C / |Inert atmosphere 2: 2-hydroxy-pyridine; triethylamine / toluene / 16 h / |Reflux; |Inert atmosphere View Scheme

1.1: sodium hydrogencarbonate / water; tetrahydrofuran 1.2: 20 °C 2.1: triethylamine; 2-hydroxy-pyridine / tert-butyl methyl ether / 18 h / 80 °C View Scheme

1: water; lithium hydroxide hydrate / 1,4-dioxane / 120 h / 40 °C 2: diphenyl phosphoryl azide; triethylamine / toluene / 0.33 h / 20 °C 3: diphenyl phosphoryl azide; triethylamine / toluene / 1 h / 65 °C 4: 1.5 h / 65 °C 5: 2-hydroxy-pyridine / tert-butyl methyl ether / 65 °C View Scheme

1: diphenyl phosphoryl azide; triethylamine / toluene / 0.33 h / 20 °C 2: diphenyl phosphoryl azide; triethylamine / toluene / 1 h / 65 °C 3: 1.5 h / 65 °C 4: 2-hydroxy-pyridine / tert-butyl methyl ether / 65 °C View Scheme

1: 1.5 h / 65 °C 2: 2-hydroxy-pyridine / tert-butyl methyl ether / 65 °C View Scheme

1.1: potassium acetate / water; dimethyl sulfoxide 2.1: sodium hydroxide 3.1: thionyl chloride 4.1: pyridine / 12 h / 40 °C 5.1: dicyclohexyl(trifluoromethylsulfonyloxy)borane; triethylamine / -78 - 0 °C 6.1: dihydrogen peroxide; lithium hydroxide hydrate / tetrahydrofuran; water / 0.25 h 6.2: Acidic aq. solution 7.1: water; lithium hydroxide hydrate / 1,4-dioxane / 120 h / 40 °C 8.1: diphenyl phosphoryl azide; triethylamine / toluene / 0.33 h / 20 °C 9.1: diphenyl phosphoryl azide; triethylamine / toluene / 1 h / 65 °C 10.1: 1.5 h / 65 °C 11.1: 2-hydroxy-pyridine / tert-butyl methyl ether / 65 °C View Scheme

1.1: thionyl chloride 2.1: pyridine / 12 h / 40 °C 3.1: dicyclohexyl(trifluoromethylsulfonyloxy)borane; triethylamine / -78 - 0 °C 4.1: dihydrogen peroxide; lithium hydroxide hydrate / tetrahydrofuran; water / 0.25 h 4.2: Acidic aq. solution 5.1: water; lithium hydroxide hydrate / 1,4-dioxane / 120 h / 40 °C 6.1: diphenyl phosphoryl azide; triethylamine / toluene / 0.33 h / 20 °C 7.1: diphenyl phosphoryl azide; triethylamine / toluene / 1 h / 65 °C 8.1: 1.5 h / 65 °C 9.1: 2-hydroxy-pyridine / tert-butyl methyl ether / 65 °C View Scheme

1.1: dicyclohexyl(trifluoromethylsulfonyloxy)borane; triethylamine / -78 - 0 °C 2.1: dihydrogen peroxide; lithium hydroxide hydrate / tetrahydrofuran; water / 0.25 h 2.2: Acidic aq. solution 3.1: water; lithium hydroxide hydrate / 1,4-dioxane / 120 h / 40 °C 4.1: diphenyl phosphoryl azide; triethylamine / toluene / 0.33 h / 20 °C 5.1: diphenyl phosphoryl azide; triethylamine / toluene / 1 h / 65 °C 6.1: 1.5 h / 65 °C 7.1: 2-hydroxy-pyridine / tert-butyl methyl ether / 65 °C View Scheme

1.1: dicyclohexyl(trifluoromethylsulfonyloxy)borane; triethylamine / -78 - 0 °C 2.1: dihydrogen peroxide; lithium hydroxide hydrate / tetrahydrofuran; water / 0.25 h 2.2: Acidic aq. solution 3.1: water; lithium hydroxide hydrate / 1,4-dioxane / 120 h / 40 °C 4.1: diphenyl phosphoryl azide; triethylamine / toluene / 0.33 h / 20 °C 5.1: diphenyl phosphoryl azide; triethylamine / toluene / 1 h / 65 °C 6.1: 1.5 h / 65 °C 7.1: 2-hydroxy-pyridine / tert-butyl methyl ether / 65 °C View Scheme

1.1: lithium hexamethyldisilazane 2.1: sodium periodate; osmium(VIII) oxide / 0 - 20 °C 3.1: dicyclohexyl(trifluoromethylsulfonyloxy)borane; triethylamine / -78 - 0 °C 4.1: dihydrogen peroxide; lithium hydroxide hydrate / tetrahydrofuran; water / 0.25 h 4.2: Acidic aq. solution 5.1: water; lithium hydroxide hydrate / 1,4-dioxane / 120 h / 40 °C 6.1: diphenyl phosphoryl azide; triethylamine / toluene / 0.33 h / 20 °C 7.1: diphenyl phosphoryl azide; triethylamine / toluene / 1 h / 65 °C 8.1: 1.5 h / 65 °C 9.1: 2-hydroxy-pyridine / tert-butyl methyl ether / 65 °C View Scheme