Study of mechanistic pathways in cross-linking reactions with palladium

Palladium-catalyzed cross-coupling reactions, including the Suzuki, Stille, and Negishi couplings, have emerged as essential methodologies in contemporary organic synthesis. Nevertheless, there is still a lack of comprehensive understanding of the molecular processes involved in these significant events that lead to the formation of C-C and C-heteroatom bonds. This paper provides a complete analysis of the fundamental mechanistic investigations conducted on the primary cross-coupling processes facilitated by palladium catalysts. The present study focuses on the examination of kinetic aspects of several stages within the catalytic cycle, namely oxidative addition, transmetalation, and reductive elimination, in the context of diverse palladium-catalyzed coupling reactions. This paper examines the influence of ligands, substrates, reaction conditions, and additives on the kinetics and mechanism of the reaction. This study emphasizes the significance of computational investigations in enhancing our understanding of Pd catalyst speciation and the architectures of intermediates. This study aims to identify both overarching patterns and variations in the systems under investigation. Additionally, the present obstacles in comprehensively understanding the specific intricacies of these mechanisms are delineated. A comprehensive comprehension of catalytic pathways will serve as the fundamental basis for the development of enhanced Pd catalysts and the expansion of these reactions to novel substrates. The inclusion of mechanistic information will provide valuable insights to develop more efficient catalytic systems based on palladium.