Sulfolanylation of malonic acid derivatives

β-Alkoxysulfolanes in the presence of equimolar amounts of sodium ethoxide react with malonic acid derivatives in which the hydrogen atom of the methylene group is activated by CN, COOR, CONH2, and SO2R substituents to give compounds that are identical to the products of the reaction with 2-sulfolene. A possible scheme for the reaction is proposed on the basis of the experimental data and the PMR spectra.