Multi-step reaction with 4 steps 1: 7.5 percent / butan-1-ol / 21 h / 140 °C2: 61 percent / 1.) ethanol, 15 deg C, 30 min; 2.) diethyl ether, 30 min.3: 53 percent / butan-1-ol / 21 h / 140 °C4: 82 percent / aq potassium permanganate / CHCl3 / 1 h / 20 °C