1: 93 percent / anhydrous ZnBr2 / CH2Cl2 / 2 h / Ambient temperature 2: 1.) m-chloroperbenzoic acid / 1.) CH2Cl2, 0 degC, 30 min., 2.) toluene, 100 degC, 4h 3: 71 percent / 12N hydrochloric acid / butan-1-ol / 1 h / 100 °C View Scheme