Thiazolium and imidazolium cations from ionic liquids as pre-catalysts in benzoin condensation–a mini review

Abstract

Synthesis of benzoins and their substituted derivatives is well known for more than a century since the original work of Liebig and W ouml hler This important strategy to create new C C bonds now uses N heterocyclic carbenes NHC as catalysts mainly derived from azolium cations obtained from different ionic liquids Although numerous reports have been published to date this article covers just the main aspects in the NHC formation from azolium pre catalysts