Base catalysis of aromatic nucleophilic substitution reactions in aprotic and dipolar aprotic solvents

Abstract

For base-catalysed aromatic nucleophilic substitution reactions in benzene, catalysis by added base is observed irrespective of whether the catalyst is a stronger or a weaker base than the nucleophile. In acetonitrile, catalysis is only observed if the catalyst has either approximately the same strength or is a stronger base than the nucleophile. These observations are shown to indicate a difference in the mechanism of catalysis in the two solvents.