The Alkaline Ethanolyses of Chlorophenyldiphenylsulfonium Halides, Chlorophenyl Phenyl Sulfones and Chloronitrobenzene in Aqueous Ethanol

Abstract

Abstract o-, m-, and p-Chlorophenyldiphenylsulfonium halides were prepared and subjected to the alkaline ethanolysis in order to compare the activating effects of o-, m-, and p-diphenylsulfonio groups with those of o-, m-, and p-phenylsulfonyl and nitro-groups. The diarylsulfonio group at either ortho or para position was found to facilitate the nucleophilic substitution of aryl chloride powerfully. While the effect of diarylsulfonio group was not only substantially larger than that of phenylsulfonyl group, but also exceeding even that of nitro group. Meanwhile, with ethoxide ion in ethanol the alkaline decomposition reaction, presumed to be initiated by the attack of ethoxide on the sulfur atom of chlorophenyldiphenylsulfonium halide, occurred competitively along with the SN reaction, but the rate of the SN reaction of p-chlorophenyldiphenylsulfonium perchlorate was found to be about 9 times larger than that of the decomposition reaction. Substitution of a methyl group at ortho to diphenylsulfonio, phenylsulfonyl and -sulfinyl groups did change very little the rates of the ethanolyses of the corresponding p-substituted chlorobenzenes, suggesting that essentially there is no or little steric inhibition for the 3d-orbital resonance with either sulfonio, sulfinyl, or sulfonyl group in the SN reaction of these compounds.