Nucleophilic Addition-Elimination Reactions of 1,2-Di-p-toluenesulfonylethene

The addition-elimination reactions of cis- and trans-1,2-di-p-toluenesulfonylethene (1 and 2 in text) with azide, methoxide, and thiophenoxide ions occur with a high degree of retention of configuration of the substrate. Trimethyl phosphite reacts with both 1 and 2 to yield dimethyl trans-2-p-toluenesulfonylethenephosphonate and methyl p-toluenesulfinate. With cyclohexylamine, the iraws-addition-elimination product is obtained with both 1 and 2. Ethylenimine gives an adduct with 1 and 2 plus the expected addition-elimination product. Phenylmagnesium bromide reacts with 1 to give trans-β-styryl p-tolyl sulfone. cis-1,2-Di-p-toluenesulfonylethene reacts with diazomethane to give 3(5)-p-toluenesulfonylpyrazole. Sodium azide reacts with 1 in dimethyl sulfoxide to give 4(5)-p-toluenesulfonyltriazole which has been shown to arise from the cyclization of troras-2-azidovinyl p-tolyl sulfone under basic conditions.