Organic reactions in ionic liquids: MgO as efficient and reusable catalyst for the Michael addition of sulfonamides to alpha,beta-unsaturated esters under microwave irradiation

The microwave-assisted Michael addition reaction of sulfonamides 1 to alpha,beta-unsaturated esters 2 was carried out in the presence of a catalytic amount of magnesium oxide (MgO) and with the ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) as a recyclable solvent affording N-alkyl sulfonamides 3 as well as N,N-dialkyl sulfonamides 4 in short reaction times.