Studies on NaI/DMSO induced retro-Michael addition (RMA) reactions on some 1,5-dicarbonyl compounds

Studies on the reaction of some 1,5-ketodiesters/1,5-diketones with NaX (X=Cl/Br/I)/DMSO have shown that under microwave/thermal conditions, facile retro-Michael addition (RMA) reaction takes place instead of formation of the expected Krapcho products. Mechanistic studies have shown that the NaI/DMSO system is a better system than NaCl/DMSO or NaBr/DMSO to promote the RMA pathway and DMSO is an essential requirement. The electrophilic halide ion could be involved in this fragmentation reaction.