Rate constant for the beta-elimination of tosyl radical from a variety of substituted carbon-centered radicals

The rate constants for the beta-elimination of tosyl radical (Ts•) from a series of carbon-centered radicals have been determined by using the radical clock methodology. Depending on the substituents R in Ts-CH2-CH(•)R radicals, the rate constants at 293 K vary by more than 2 orders of magnitude inthe range of 10(3)-10(6) s(-1). The lowest values were found for the 2-naphthyl and carbamoyl substituents, whereas the benzyl substituent is located at the other extremity. The effect of the substituent upon the stabilization of the starting radical exerts a predominant influence in this reaction in decreasing the rate of fragmentation.