Aryl imidazylates and aryl sulfates. Novel electrophiles in metal-free ArSN1 reactions

Some oxygen-bonded substituents were investigated as leaving groups in photoinduced ArSN1 reactions. Irradiation of aryl imidazylates and of the corresponding imidazolium salts mainly caused homolysis of the ArO−S bond. However, previously unexplored trifluoroethoxy aryl sulfates were found to undergo efficient metal-free arylation. The sulfates were conveniently generated in situ by dissolving the corresponding imidazolium salts in basic 2,2,2-trifluoroethanol.