1: pyridinium p-toluenesulfonate / toluene / |Inert atmosphere; |Reflux; |Dean-Stark 2: diisobutylaluminium hydride / dichloromethane; toluene / 3 h / -78 °C / |Inert atmosphere 3: triphenylphosphine; diethylazodicarboxylate / tetrahydrofuran / 1.5 h / -78 - 20 °C / |Inert atmosphere 4: AD-mix-βreg;; methanesulfonamide; osmium(VIII) oxide / dichloromethane; #tert!-butyl alcohol; water / 72 h / 20 °C / |Inert atmosphere 5: pyridinium p-toluenesulfonate / toluene / 2 h / 90 °C / |Inert atmosphere 6: lithium hydroxide hydrate / methanol; tetrahydrofuran / 0.5 h / 20 °C / |Inert atmosphere 7: boron tribromide / dichloromethane / -78 - 20 °C / |Inert atmosphere View Scheme