Elimination–addition mechanisms of sulphonyl group transfer: evidence for a dicarbanionic intermediate in the alkaline hydrolysis of aryl methylsulphonylmethanesulphonate esters

Abstract

Kinetic evidence has been obtained from the hydrolysis of the title compounds that is consistent with a dissociative mechanism; ionization of the substrate is followed by the slow unimolecular breakdown of the conjugate base to phenoxide ion and sulphene, but at hight pH values a further ionizatio occurs to give a dicarbanion which undergoes E1-elimination of phenolate ion to yield a sulphene anion in the rate determining step.