The S_N mechanism in aromatic compounds. XX. The nucleophilicity of phenoxides

Abstract

The reactions of a series of phenoxides in MeOH with 1-chloro-2,4-dinitrobeneene (and in one case with picryl chloride also) have been measured. They are compared with each other and with the OMe^- reaction. The reactions of the several phenoxides show a relationship between basicity and nucleophilicity analogous to the Bronsted relationship between acid-base strength and catalytic activity, but the relationship does not include OMe^-. The phenoxide reactions also obey the Hammett equation with a ρ value similar to those for ionization of phenols in water and alcohols. General features of nucleophilicity and basicity are discussed in outline.