triethylamine in tetrahydrofuran; dichloromethane T=20°C; 0.5 h;

1.1: triethylamine; acetic anhydride / o-xylene / 0.5 h / 20 °C 1.2: 50 h / 150 °C 2.1: lithium hexamethyldisilazane / tetrahydrofuran / 0.75 h / -20 °C 2.2: 1.17 h / -20 - 0 °C 3.1: boron tribromide / dichloromethane / 7.33 h / 20 - 34 °C / |Inert atmosphere 4.1: ethanol / 18.17 h / 0 - 26 °C / |Inert atmosphere 5.1: di-isopropyl azodicarboxylate / tetrahydrofuran / 1.08 h / -5 - 0 °C 5.2: 18.5 h / 20 °C 6.1: triethylamine / dichloromethane / 0.17 h / 20 °C 6.2: 21 h / 20 - 30 °C View Scheme

1.1: triethylamine; acetic anhydride / o-xylene / 0.5 h / 20 °C 1.2: 50 h / 150 °C 2.1: lithium hexamethyldisilazane / tetrahydrofuran / 0.75 h / -20 °C 2.2: 1.17 h / -20 - 0 °C 3.1: boron tribromide / dichloromethane / 7.33 h / 20 - 34 °C / |Inert atmosphere 4.1: ethanol / 18.17 h / 0 - 26 °C / |Inert atmosphere 5.1: di-isopropyl azodicarboxylate / tetrahydrofuran / 1.08 h / -5 - 0 °C 5.2: 18.5 h / 20 °C 6.1: triethylamine / dichloromethane / 0.17 h / 20 °C 6.2: 21 h / 20 - 30 °C View Scheme

1: With diisobutylaluminium hydride in toluene T=-78°C; 3 h; 2: in methanol; toluene

in methanol; toluene

1.1: diisobutylaluminium hydride / dichloromethane / 2.25 h / -20 °C / |Inert atmosphere 2.1: n-butyllithium / tetrahydrofuran; hexane / 1.33 h / -76 - -73 °C / |Inert atmosphere 2.2: 2.33 h / -73 °C / |Inert atmosphere 3.1: hydrogenchloride / water / 0.75 h / 10 - 20 °C / |Inert atmosphere View Scheme