1.1: n-butyllithium / tetrahydrofuran; hexanes / -75 °C / Inert atmosphere 1.2: 1 h / -75 °C 2.1: lithium chloride / tetrahydrofuran / 20 °C 2.2: 1 h / -10 °C / Inert atmosphere 3.1: hydrogen / Lindlar's catalyst / ethyl acetate 4.1: sodium tetrahydroborate; methanol / 0.5 h / -7 °C 5.1: 1H-imidazole / N,N-dimethyl-formamide / Cooling with ice 6.1: diisobutylaluminium hydride / toluene / 1 h / -70 °C / Inert atmosphere 7.1: n-butyllithium / tetrahydrofuran / Inert atmosphere; Cooling with ice 8.1: pyridinium p-toluenesulfonate / dichloromethane / 20 °C 9.1: 9-bora-bicyclo[3.3.1]nonane; dihydrogen peroxide / tetrahydrofuran / 3 h / Inert atmosphere; Cooling with ice 10.1: tetrabutyl ammonium fluoride / tetrahydrofuran 11.1: Jone's reagent / water; acetone / 1 h / 0 °C 12.1: trifluoroacetic acid / dichloromethane / 20 °C 13.1: trifluoroacetic acid / dichloromethane / 20 °C View Scheme

1.1: n-butyllithium / tetrahydrofuran; hexanes / -75 °C / Inert atmosphere 1.2: 1 h / -75 °C 2.1: lithium chloride / tetrahydrofuran / 20 °C 2.2: 1 h / -10 °C / Inert atmosphere 3.1: hydrogen / Lindlar's catalyst / ethyl acetate 4.1: sodium tetrahydroborate; methanol / 0.5 h / -7 °C 5.1: 1H-imidazole / N,N-dimethyl-formamide / Cooling with ice 6.1: diisobutylaluminium hydride / toluene / 1 h / -70 °C / Inert atmosphere 7.1: n-butyllithium / tetrahydrofuran / Inert atmosphere; Cooling with ice 8.1: pyridinium p-toluenesulfonate / dichloromethane / 20 °C 9.1: 9-bora-bicyclo[3.3.1]nonane; dihydrogen peroxide / tetrahydrofuran / 3 h / Inert atmosphere; Cooling with ice 10.1: tetrabutyl ammonium fluoride / tetrahydrofuran 11.1: Jone's reagent / water; acetone / 1 h / 0 °C 12.1: trifluoroacetic acid / dichloromethane / 20 °C View Scheme

1: With water; sodium hydroxide in ethanol 3 h; Reflux; 2: With hydrogenchloride in ethanol; water T=20°C; pH=2;