Palladium‐N‐heterocyclic Carbene Complexes: Synthesis, Characterization and Catalytic Application of C−H Activation for Carboxaldehyde Derivatives

Abstract A series of palladium‐ N ‐heterocyclic carbene complexes ( 2 a‐e ) were synthesized from corresponding N ‐heterocyclic carbene precursors ( 1 a‐e ) in good yields. The structural analysis of all novel compounds was done by spectroscopic methods and elemental analysis was also performed to evaluate the purity of the complexes. Further confirmations of complexes 2 a‐d were provided by X‐ray crystallography technique. Under optimized reaction conditions, the catalytic activity of the palladium‐ N ‐heterocyclic carbene complexes was reviewed by direct arylation of furan‐2‐carboxaldehyde and 1‐methylpyrrole‐2‐carboxaldehyde with varied aryl halides. This arylation showed productive and selective reaction at the C5‐position of heteroaryl derivatives.