1.1: toluene-4-sulfonic acid; orthoformic acid triethyl ester / benzene / 20 °C 2.1: PCC-alumina / benzene / 36 h / 20 °C 3.1: lithium aluminium tetrahydride / tetrahydrofuran / 2 h / Reflux 4.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / 0 - 20 °C 4.2: 20 °C 5.1: 2 h 6.1: tri-n-butyl-tin hydride; 1,1'-azobis (cyclohexanecarbonitrile) / toluene / 4 h / Reflux; Inert atmosphere 7.1: hydrogenchloride; water / 0.25 h View Scheme

1.1: toluene-4-sulfonic acid; orthoformic acid triethyl ester / benzene / 20 °C 2.1: PCC-alumina / benzene / 36 h / 20 °C 3.1: lithium aluminium tetrahydride / tetrahydrofuran / 2 h / Reflux 4.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / 0 - 20 °C 4.2: 20 °C 5.1: 2 h 6.1: tri-n-butyl-tin hydride; 1,1'-azobis (cyclohexanecarbonitrile) / toluene / 4 h / Reflux; Inert atmosphere 7.1: hydrogenchloride; water / 0.25 h 8.1: pyridine; sodium tetrahydroborate; sodium hydroxide / methanol; water / Cooling with ice View Scheme