perchloric acid in ethanol 1 h;

ethanol unter Zusatz von wasserhaltiger Phosphorsaeure;

hydrogen; Au/Fe(OH)x T=100°C; P=15001.5 Torr; 11 h; Product distribution; Further Variations:Catalysts;

hydrogenchloride

cation-exchange resin KU-2 and KU-2-8 in water T=20 - 30°C; 5 h;

zinc(II) chloride in ethyl acetate T=20°C; 24 h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

1: ZnCl2 / ethyl acetate / 24 h / 20 °C 2: H2, 2,4-dimethoxy-2-ethoxy-6,10-dimethylundeca-5,9-diene / Ni / ethanol / 50 °C / 38000 - 60800 Torr 3: pyridinium chlorochromate, methoxy alcohol (VIb) / CH2Cl2 / 5 h / 20 - 22 °C 4: 80 percent / toluene-p-sulfonic acid, quinoline / toluene / 130 - 140 °C View Scheme

(i) BF3-Et2O, (ii) aq. NaOAc, AcOH; Multistep reaction;