Intermolecular direct catalytic cross-Michael/Michael reactions and tandem Michael/Michael/aldol reactions to linear compounds

Catalytic cross-Michael/Michael reactions of nitroalkenes and ethyl acrylate with pronucleophiles including thiols, dimethyl methylmalonate, and 2-nitropropane to linear three-component products were developed by using a catalytic amount of DBU in DMSO. Tandem sulfa-Michael/Michael/aldol reactions of a thiol, a nitroalkene, ethyl acrylate, and an aldehyde proceeded to give a linear four-component product. The high nucleophilicity of in situ-formed nitronate anions and ester enolates in DMSO was important for the present multi-component cascade reactions using pronucleophiles that had protons with relatively high acidity.