NEW DECARBOXYLATION, DE-ETHOXYCARBONYLATION AND DESULFONYLATION, FOLLOWED BY SULFENYLATION OF SOME HALF-ESTERS OF MALONIC-ACIDS AND ALPHA-SULFONYLMALONIC ESTERS

The sulfenylation of some half-esters of malonic acids and some alpha- sulfonylmalonic esters with several sulfenylating reagents was investi gated. Evidence was provided that in the case of the half-esters, in w hich NaH-dimethyl sulfoxide was employed, the formation of alpha,alpha -disulfenylated carboxylic esters may occur by two different reaction sequences, initiated either by dianion formation or decarboxylation. I t is shown that, in the case of the alpha-sulfonylmalonic esters, in w hich diazabicyclooctane in refluxing toluene was employed, two competi tive reactions may take place: de-ethoxycarbonylation or desulfonylati on, both followed by sulfenylation.