Palladium And Visible Light Co-Catalyzed Insertion Reaction Of Olefins Into Aryl C-I Bonds

In the past decade,the strategy of forming carbon halide bonds through transition metal catalysis has rapidly developed in organic synthesis applications,mainly including Heck reaction,Suzuki reaction,Kumada reaction,etc.As an effective intermediate,carbon halogen bond can also be used to construct Carbon-carbon bond and carbon hetero bond.The use of transition metal palladium as a catalyst for the formation of carbon halide bonds through the dual electron redox pathway is an effective approach^[1],but this process mostly requires high steric hindrance of electron rich ligands and high temperatures,which make the operation cumbersome and complex.In recent years,due to the rapid development of visible light and palladium Synergistic catalysis system,the organic synthesis process catalyzed by transition metals under harsh conditions can now be realized under mild conditions.Moreover,light excited palladium complexes can significantly accelerate known palladium catalytic conversion,such as Heck and Negishi cross Coupling reaction of aryl halides.With the introduction of visible light catalysis,not only does the reaction become more convenient,but the substrate also has a wider range of applications and good functional group compatibility.In addition,the catalytic amount of ligand also plays an important role in the photo Catalytic cycle.It can not only gain or lose electrons,but also provide energy to promote the reaction,thus improving the safety and controllability of the reaction,making the reaction more efficient and green.The strategy of transition metal palladium and photo Synergistic catalysis has opened up a new way for developing new mild and efficient organic synthesis and transformation.This paper will focus on the synergistic catalysis of visible light and transition metal palladium for the insertion of olefins into aryl carbon-iodide bonds as follows:1.The insertion reaction of olefins into aryl C-I bonds through the activation of aryl C-I bonds using a visible light/Palladium synergistic catalysis strategy.The reaction was successfully synthesised to generate various iodinated heterocyclic and carbocyclic compounds using N-methacrylamide as the reaction substrate,the feedstock itself as a source of iodine,and palladium chloride and visible light as the catalytic system.2.In this project,we examined various palladium catalyst precursors in the reaction,and also examined and screened the nitrogen ligands and phosphine ligands in the reaction;on this basis,we studied the reaction parameters such as reaction time,solvent and light source to obtain the best catalytic reaction system.After establishing the optimal reaction conditions,we examined its adaptability and found that the common groups-F,-Cl,-Br,-CF₃,-CN,-OCH₃.Finally,we conducted a preliminary exploration of the reaction mechanism and successfully captured the corresponding radical intermediates by radical trapping agents,which provided a basis for the reaction mechanism of monovalent palladium.In conclusion,we developed an efficient visible light and palladium synergistic catalytic insertion reaction of olefins to aryl C-I bonds.The method is capable of yielding products in good yields under mild conditions with a wide range of substrates and functional group tolerance for a number of electron-absorbing and electron-donating groups.This strategy provides novel reaction strategies for the construction of various C-I bonds.