1.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / 0 - 20 °C 1.2: 20 °C 2.1: 2 h 3.1: tri-n-butyl-tin hydride; 1,1'-azobis (cyclohexanecarbonitrile) / toluene / 4 h / Reflux; Inert atmosphere 4.1: hydrogenchloride; water / 0.25 h View Scheme

1.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / 0 - 20 °C 1.2: 20 °C 2.1: 2 h 3.1: tri-n-butyl-tin hydride; 1,1'-azobis (cyclohexanecarbonitrile) / toluene / 4 h / Reflux; Inert atmosphere 4.1: hydrogenchloride; water / 0.25 h 5.1: pyridine; sodium tetrahydroborate; sodium hydroxide / methanol; water / Cooling with ice View Scheme