Fused Polycyclic NHC Ligands in Gold Catalysis: Recent Advances

Thanks to their appealing properties, N-heterocyclic carbene (NHC) ligands gained considerable significance as highly powerful ancillary ligands in gold catalysis. While NHC-gold catalysis is still dominated by the classical imidazole-derived NHC ligands, annelated NHC systems, which feature fused aromatic rings to the carbenic heterocycle, have drawn wider attention over the last few years thanks to their unique structural and electronic properties. Fused polyaromatic NHCs are indeed versatile platforms that offer unique stereoelectronic tuning possibilities to exhibit superior activity and/or selectivity in NHC-gold catalysis. But their polycyclic scaffolds also provide further scope for functionalization and the introduction of chirality, stimuli-responsiveness, or cooperativity within the NHC-gold systems. In this review, the recent advances in this area are discussed and a particular attention is drawn on the unique role of the annelation.

Automated summary

N-heterocyclic carbene (NHC) ligands have gained considerable importance in gold catalysis due to their appealing properties. Fused polyaromatic NHCs, featuring fused aromatic rings, have attracted wider attention in recent years for their unique structural and electronic properties. These versatile platforms offer superior activity and/or selectivity in NHC-gold catalysis and provide opportunities for further functionalization, chirality introduction, stimuli-responsiveness, or cooperativity within the NHC-gold systems.