1: CF3COOH, Ethyl(vinyl)ether, 10percent KOH / methanol / 1 h 2: CrO3 / CH2Cl2; pyridine / 0.17 h 3: 10percent KOH / H2O / 22 h / Heating 4: 2N HCl / acetone / 0.5 h / Ambient temperature View Scheme