Recent Advances on N-Heterocyclic Carbene-Palladium-catalyzed Heck Reaction

Heck reaction is a synthetically important C-C bond forming coupling reaction happening between alkenes and aryl or vinyl halides catalyzed by palladium complexes to form substituted alkenes. This review focusses on the recent advancements in the development of various types of N-heterocyclic carbene (NHC) ligands coupled with palladium catalyst that can catalyze Mizoroki-Heck reactions. NHC ligands have unique characteristic nature, and hence widely used in homogeneous catalysis. Generally, they have good sigma-donating and sparingly pi-accepting properties. It is more stable and shows superior pi-accepting properties when compared to phosphine ligands that is under prominent studies. Thus, they can stabilize large extend of metal oxidation states and have high thermal stability. Most of the catalysts outlined here provide efficient and green synthetic route for the development of C-C coupled bond formations. The review encompasses literature from 2017 to 2021.