Electrophilic additions to alkenes. Part VI. Substituent effects on the rates of reaction of arylsulphenyl bromides with cyclohexene

Abstract

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, ρ⁺. The rates of addition of these sulphenyl bromides relative to those of the corresponding chlorides are essentially constant, the average value for k_Br:k_Cl being 2·4. The constancy of this ratio indicates that the first step in the suggested mechanism is rate-limiting.