Multicomponent Synthesis of Unsymmetrical 4,5-Disubstituted Imidazolium Salts as N-Heterocyclic Carbene Precursors: Applications in Palladium-Catalyzed Cross-Coupling Reactions.

Various novel (a)chiral 4,5-disubstituted 1-aryl-3-alkyl-imidazolium salts were synthesized via the multicomponent reaction of diketone derivatives, sterically congested arylamines, and alkylamines. Moreover, two novel unsymmetrical bulky cycloalkyl-based NHC-Pd complexes proved highly active as catalysts for Suzuki-Miyaura and Negishi cross-coupling reactions.