Aldehydes undergo smooth conjugateaddition to α,β-unsaturatedketones in the presence of 5-(2-hydroxyethyl)-1,3-thiazolium halides and DBU adsorbed onto the surface of basic alumina under microwave irradiation and solvent-free conditions to afford 1,4-diketones in enhanced yields and reduced reaction times compared to conventional methods.
Bi(OTf)3 immobilized in 1-butyl-3-methylimidazolium tetrafluoroborate [bmim]BF4 has been utilized for the first time as a novel and reusable catalyticsystem for the synthesis of heteroaromatics such as furan, pyrrole and thiophene derivatives from 1,4-diketones. This new procedure offers significant improvements in reaction rates and yields. The recovered ionic liquid containing bismuth triflate can