acetyl chloride in methanol Inert atmosphere;

1: 88 percent / p-toluenesulfonic acid monohydrate / aq. ethanol / 168 h / Heating 2: 78 percent / CF3SO3H / hexane; CH2Cl2 / 0.42 h / Heating 3: diisobutylaluminum hydride / diethyl ether; hexane / 1.) -78 deg C, 25 min, 2.) 0 deg C, 2 h, then 25 deg C, 2 h View Scheme

1: 78 percent / triethylamine / CH2Cl2 / 7 h / Ambient temperature 2: 85 percent / tri-n-butyltin hydride, AIBN / benzene / 2 h / Heating 3: 68 percent / Jones reagent / acetone / 0 °C View Scheme