Study Of Iridium (Ⅲ)-Catalyzed Direct Arylation Of C-H Bonds With Diaryliodonium Salts

The content of my research is divided into the following three parts:1. Study of Iridium Catalyzed Direct Arylation of sp3 C-H bondThe method of transition metal catalytic activation of C-H bond has become an integral part of the organic synthesis, and the field has been highly concerned by the chemical community in recent years. The aliphatic C-H bonds, which are ubiquitous in. organic molecules, are most challenging targets for effective and selective functionalization to construct a variety of C-C and C-heteroatom bonds. Under the catalysis of transition metal, it can achieve that direct arylarion of C-H bonds. Direct C-H arylation has great advantages over traditional coupling protocols and it can overcome the traditional method needs multistep operation. The β-arylated ketoxime is a prominent structural motif which can convert to many bioactivenatural products and pharmaceutically important compounds. We use a trivalent Iridium metal complexes as catalysts, diaryliodonium salts as arylation sources, and we successfully achieve introduce a phenyl group in the β-position of ketoximes via sp3 C-H activation. This method has the characteristics of atomic economy, good reaction substrate compatibility and high region selectivity. By means of density functional theory (DFT) calculation, the formation process of the reaction is explained from the theoretical point of view.2. Study of Arylation of heterocyclesSince the heterocycles including pyridine, pyrazine, quinoline, pyrazole, isoxazole, and so on are commonly occurring structural motifs found in numerous pharmaceuticals and biologically active compounds, we envisioned that a reliable method for direct arylarion of these heterocycle-directed sp3 C-H bonds would be very meaningful. Through continuous exploration and optimization of the reaction conditions, we find out the optimal reaction conditions. Using [IrCp*Cl2]2 acts as a catalyst, AgNTf2 as additives. PivOH.4A MS and cyclohexane, diaryliodonium salts as arylation sources, at 100℃ conditions, we successfully achieve the arylation of heterocyclic compounds. Under the reaction system, it was found that the single substituted aryl product was obtained, and with no disubstituted byproduct detected by GC-MS. This transformation can not only be compatible with the six-membered ring heterocycles, but also can get a higher yield of the six-membered ring heterocycles. This transformation has good practical value and application prospects for the modification of drugs and biological active molecules.3. ortho C-H Arylation of Various Arenes and OlefinsAlthough the direct sp2 C-H arylation reactions have been well-developed in the presence of different transition metals including Pd, Ni, Cu, Ru, Rh, and so on, Ir(Ⅲ)-catalyzed C-H arylation of arenes still remains relatively rare. The C-H sp2 bond of aryl compound was successfully realized by using half-sandwich Ir(Ⅲ) complexes as catalyst, and the reaction system had very high functional group compatibility. Including pyridine compounds, amide compounds as well as ketoximes can be very good to get the target arylation product. At the same time, the olefin compound in the presence of the drection group of the amide, the ketoximes and the carboxylic acid can successfully implement arylation of the C-H bond. Remarkably, these coupling reactions occurred with complete Z selectivity. This stereoselectivity is highly valuable because of its potential synthetic applications.