Michael addition of nitromethane to alpha,beta-unsaturated carbonyl compounds over solid base catalysts

Michael additions of nitromethane to cu,P-unsaturated carbonyl compounds (m ethyl crotonate, butene-2-one, 2-cyclohexene-1-one, and crotonaldehyde) wer e carried out at 273 K or 323 K over solid base catalysts such as alumina-s upported potassium fluoride and hydroxide, alkaline earth oxides and lantha num oxide. For all Michael additions of nitromethane, KF/alumina and KOH/al umina exhibited high activities, while MgO and CaO exhibited no activity fo r methyl crotonate and butene-2-one, but low activities for 2-cyclohexene-1 -one and crotonaldehyde. The SrO, BaO, and La2O3 exhibited practically no a ctivities for all Michael additions examined. The reactivity of each alpha, beta-unsaturated carbonyl compound is discussed on the basis of the surface properties of catalyst and the chemical properties of the alpha,beta-unsat urated carbonyl compound. (C) 2000 Elsevier Science B.V. AU rights reserved .