1: 71 percent / potassium tert-butoxide / dimethylformamide; benzene 2: 57 percent / tetrabutylammonium fluoride / tetrahydrofuran 3: 93 percent / carbon tetrabromide; triphenylphosphine / CH2Cl2 4: 80 percent / potassium tert-butoxide / dimethylsulfoxide 5: 95 percent / ozone / methanol View Scheme