Methyl-Transfer Reactions. 6. Arenesulfonates as Nucleophiles and Leaving Groups. Methyl Trinitrobenzenesulfonate

Article abstract of DOI:10.1021/jo00163a020

The methyl-transfer reactions from several substituted methyl arenesulfonates to potassium benzenesulfonate in sulfolane have been studied with respect to both rates and equilibria.Because the reactions were followed by proton NMR of the methoxy group, only cases of methyl arenesulfonates with quite distinct methoxy chemical shifts from the unsubstituted ester could be studied, and this, in fact, required the use of ortho substituents.Hammett plots for these data were thus impossible, but a plot of log k₊ vs. log K, although somewhat scattered, did allow an estimation of the rate of the identity reaction for the unsubstituted compound.These methyl arenesulfonates, as well as methyl iodide, were placed roughly on the scale of equilibrium methylating agents studied earlier in the same solvent.Methyl 2,4,6-trinitrobenzenesulfonate is a very reactive substance not compatible with sulfolane.It is soluble and stable only in thionyl chloride among a large number of solvents attempted and methylates a few weak nucleophiles more extensively than methyl trifluoromethanesulfonate.