Highly efficient synthesis of carboacyclic nucleosides catalyzed by zinc oxide in 1-butyl-3-methylimidazolium bromide (ZnO/[bmim]Br)

Michael addition of pyrimidine and purine nucleobases to substituted as well as unsubstituted α,β-unsaturated esters efficiently proceeds in the presence of catalytic amount of zinc oxide in ionic liquid 1-butyl-3-methylimidazolium bromide (ZnO/[bmim]Br) under microwave irradiation to afford carboacyclic nucleosides, as biologically important compounds, in good to excellent yields and in short reaction times.