1: 77 percent / acetone / 1 h 2: 70 percent / sodium hydride / dimethylsulfoxide / 1 h / Ambient temperature 3: 98 percent / m-chloroperbenzoic acid / CHCl3; diethyl ether / 0 °C 4: 50 percent / aq. hydrochloric acid, acetic acid / 1 h / 50 °C View Scheme