potassium dichromate; sulfuric acid; tetra(n-butyl)ammonium hydrogensulfate in dichloromethane T=-10°C; 2 h;

potassium dichromate; aluminum oxide; sulfuric acid; tetra(n-butyl)ammonium hydrogensulfate in ethanol; acetone 1.) 24 h, r.t, 2.) CH2Cl2, -5 deg C, 3 h.; Yield given. Multistep reaction;

1: 80 percent / methanol / 10 h / Ambient temperature 2: 88 percent / Lithium aluminium hydride / tetrahydrofuran / 0.5 h / 0 °C 3: 1.) boron triluoride etherate, 2.) p-toluenesulfonic acid / 1.) acetone-water, r.t, 2 h, 2.) r.t, 12 h. View Scheme