Recent Advances in Benzimidazole Based NHC-Metal Complex Catalysed Cross-Coupling Reactions

摘要

In recent years,there has been a substantial increase in the development of efficient,environmentally compatible and cost-effective catalysts as a replacement for conventional metal catalysts.Among several catalysts developed,metal-based NHeterocyclic carbene(NHC)catalysts have garnered significant attention due to the unique steric and electronic properties imparted by NHCs,making them suitable for a broad spectrum of chemical transformations.Over a decade,benzimidazole based NHCs have been broadly investigated for the synthesis of metal complexes for a variety of catalytic processes.The interesting properties of benzimidazole scaffolds such as the ease of tailoring its electronic and steric properties via simple synthetic modifications,aids in achieving potential catalysts for cross-coupling reactions and other hydrofunctional transformations.This review focuses on the synthetic approaches developed over recent years(2015-2021)concerning the structural tuning and modulation of the benzimidazole derived NHC ligands to generate catalytically active metal complexes for cross-coupling reactions such as Heck,Suzuki,Sonogashira,Kumada and dehydrogenative cross-coupling reactions.