ELECTROPHILIC ADDITIONS TO ALKENES .6. SUBSTITUENT EFFECTS ON RATES OF REACTION OF ARYLSULPHENYL BROMIDES WITH CYCLOHEXENE

The rates of addition of a series of 4-substituted 2-nitrobenzenesulphenyl bromides to cyclohexene have been measured in acetic acid solution at 25.0° A value of -0.667 is obtained for the reaction constant, p+. The rates of addition of these sulphenyl bromides relative to those of the corresponding chlorides are essentially constant, the average value for k Br:kCl being 2.4. The constancy of this ratio indicates that the first step in the suggested mechanism is rate-limiting.