New decarboxylation, de-ethoxycarbonylation and desulfonylation, followed by sulfenylation of some half-esters of malonic acids and α-sulfonylmalonic esters

Abstract

The sulfenylation of some half-esters of malonic acids and some α-sulfonylmalonic esters with several sulfenylating reagents was investigated. Evidence was provided that in the case of the half-esters, in which NaH–dimethyl sulfoxide was employed, the formation of α,α-disulfenylated carboxylic esters may occur by two different reaction sequences, initiated either by dianion formation or decarboxylation. It is shown that, in the case of the α-sulfonylmalonic esters, in which diazabicyclooctane in refluxing toluene was employed, two competitive reactions may take place: de-ethoxycarbonylation or desulfonylation, both followed by sulfenylation.