CO2 Transformations in Ionic Liquids: In Situ NHC-Cu Formation for Carbonate and Carbamate Production

A simple and straightforward one-pot reaction using Cu salts and imidazolium-based ionic liquids (ILs) efficiently converts CO2 and propargylic alcohols into various acyclic and cyclic carbonates and carbamates with excellent yields (98%) and selectivities (99%), all without the need for additional additives or bases. Various Cu salts and ionic liquid structures have been evaluated, demonstrating that by optimizing the combination of the IL cation and anion, the catalyst's performance is significantly enhanced under mild reaction conditions. The CuI/[EMI]·[Levu] system exhibited excellent catalytic activity and recyclability. A mechanistic study was conducted, revealing the formation of an N-heterocyclic carbene-copper (NHC-Cu) complex intermediate, and a plausible mechanism has been proposed, highlighting the multifunctional role of the ionic liquid.