THE SOLVOLYSIS OF ARENESULFINATES, SULFUR–OXYGEN VERSUS CARBON–OXYGEN BOND FISSION

Abstract

The base-catalyzed solvolysis of p-methoxyneophyl benzenesulfinate and the corresponding 2,6-dimethyl-, 2-methyl-, 4-methyl-, and 2-chloro-benzenesulfinates has been studied in ethanol and aqueous ethanol. The reactions involve sulfur–oxygen bond fission. The rate of sulfur–oxygen bond fission is decreased by the introduction of two methyl groups ortho to the sulfur. The rate decrease may be partly due to steric hindrance to nucleophilic attack on the sulfinate sulfur, but this effect is very small compared to the effect in carboxylate ester hydrolysis. The reactions are catalyzed by ethoxide, acetate, and pyridine. Reaction is very slow in the presence of 2,6-lutidine. With certain arenesulfinate esters one can control the reaction to give sulfur–oxygen or carbon–oxygen bond fission by choice of an appropriate base.