| Abstract
| - Introduction of polyfluoroalkoxy and polyfluoroalkylthio substituents in aromatic rings can beachieved with mild conditions and short times thorough reaction of concentrated solutions ofdinitrobenzenes in DMF with polyfluoro alcohols and polyfluoro thiols in moderate excess, in thepresence of excess tetrabutylammonium fluoride as a base. Mechanistic studies suggest that underthese conditions a fast radical chain mechanism operates. This mechanism is elicited by oxidationof a Meisenheimer complex and proceeds through a radical aromatic substitution with thepolyfluoroalkoxy or the polyfluoroalkylthio radicals as key intermediates. At low concentrations,entrainment can be achieved with superoxide anion. A rationale for this effect is discussed. Answersto particular questions about the proposed mechanism are achieved through a theoretical study atthe B3LYP/6-31+G(d,p) level. Specifically, the competition between the radical mechanism andthe corresponding polar one (classical SNAr reaction) is studied in that way, with the conclusionthat the key steps of the radical mechanism in our reaction conditions (polar aprotic solvent) areat least as efficient as the ones of the polar one, thus justifying the observed kinetic advantage forthe chain reaction in the conditions where an efficient initiation occurs.
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