Rate constants 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-CH(2)-CH*R radicals, the rate constants at 293 K vary by more than 2 orders of magnitude in the 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.
Timokhin
Vitaliy I
VI
Laboratoire de Chimie Moléculaire Organique, UMR 6517, Boite 562, Faculté des Sciences St Jérôme, Université d'Aix-Marseille III, Av. Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France.
Gastaldi
Stéphane
S
Bertrand
Michèle P
MP
Chatgilialoglu
Chryssostomos
C