Recent Development in the Catalytic Applications of Pd-NHC (NHC=N-Heterocyclic Carbene) Compounds in Amide C-N Activation Reactions

Palladium-catalyzed C-N bond activation of amide is a important but very challenging research area in organic chemistry. This reaction represents a powerful and straightforward method for the preparation of various carbonyl compounds under mild reaction conditions. One notable advancement in this area is related to the design and development of multifunctional NHC ligands and other throw-away ligands. The reasonable design of ligands could not only improve the activity of catalyst, but also help to adjust the reaction selectivity. In this review, we summarized the structure-activity relationship of those catalysts with different ligand skeletons and their applications in cross-coupling reactions including Suzuki-Miyaura coupling, Buchwald-Hartwig amination and direct C-H acylation, via amide C-N bond activation. On this basis, we analyze the current bottlenecks encountered in Pd-NHC-catalyzed amide C-N activation reactions, and envisage the future development of this field.