Recent Synthetic Methods for N ‐Heterocyclic Carbene Precursors: Beyond Cyclization as the Key Step †

Comprehensive Summary The N ‐heterocyclic carbene (NHC), as an electron‐rich nucleophilic species, constitutes an important class of ligands for transition metals and plays a key role in organocatalysis. Consequently, diverse NHCs have been developed in recent years. Moreover, to access NHCs with novel scaffolds, innovative synthetic methods of NHC precursors have emerged. Given the prevalence of carbene precursors in organometallic and organocatalytic processes, this review summarizes the synthesis of imidazolium, imidazolinium, thiazolium, and triazolium salts. Finally, we propose future research directions for developing highly efficient novel NHCs. Key Scientists