Michael Addition versus Cycloaddition-Condensation of Ethyl Nitroacetate with Electron-deficient Olefins

Abstract. Ethyl nitroacetate reacts, in the presence of a base, with electron-poor olefins to give either the Michael adduct 3 or the cycloadduct 4, as a result of water elimination. The proportion of the two products depends on the reaction conditions and changes in the course of the process. Kinetic profiles for the two reactions show that the cycloaddition-condensation is subject to long induction time that dramatically decreases upon addition of a copper salt to the catalytic system: the drop of induction time causes an increase in the proportion of cycloadduct 4, which is often the sole reaction product. This is the first report on the selective formation of products 3 and 4 from a primary nitro compound, by modulating the catalytic system.