Rh(â…¢)-catalyzed Aromatics C-H Activation Fuctionalization Reaction

Transition metal-catalyzed C-H activation reaction is one of the most powerful and efficient methords for the constraction of a variety of functional chemical bond (C-O, C-N, C-S, C-C). Thus, it has been widely used for the synsthesis of complaxed natural products, pharmaceuticals and advanced materies. The reaction has many advantages, such as high selectivity, mild reaction condition, high atom economy. In recent years, with the development of organometallic chemistry, transition metal-catalyzed C-H activation reaction has caused more and more peoples’attention so it has been becoming a hot spot of current research.Transition metal-catalyzed C-H activation reaction mainly concentrated in Pd, Cu, Ru, Fe, Rh, etc. Compared with other metals, Rh (Ⅲ)-catalyzed C-H activation has its advantages, for example high catalytic efficiency, high factional group compatibility, a broad substrate scope, and operational simplicity. Rh-catalyzed C-H functionalization has emerged as a novel strategy in the traditional retro systhetic analysis of total synthesis. It has been a central problem of the methodology during the past decades. This thesis mainly focused on the mew methord of Rh (Ⅲ)-catalyzed C-H activation. The main content is as follows:Chapter one, The review of Rh (Ⅲ)-catalyzed aromatics C-H activation reactionThis chapter simply reviews the concept, advantage, mechanism and significance of C-H activaon, the research progress of Rh (Ⅲ)-catalyzed aromatics C-H activation and the research significance of this paper.Chapter two, Rh (Ⅲ)-catalyzed redox-neutral C-H arylation via rearomatizationRh (Ⅲ)-catalyzed arylation of arenes bearing a chelating group has been realized via a redox-economy process using 4-hydrocyclohexa-2,5-dienones as the arylating reagents, leading to the synthesis of 3-arylated phenols. This redox-neutral proceeds via a C-H activation pathway with rearomatization being the driving force.Chapter three, Rh (Ⅲ)-catalyzed C-C and C-O coupling of quinoline N-Oxides with alkynes.We have developed a rhodium (Ⅲ)-catalyzed redox-neutral coupling of quinoline N-oxide with internal alkynes, leading to the synthesis of substituted acetophenones. This system represents the first example that combines C-H activation and OAT. The combination of different important areas in catalysis may allow opportunity to expand the scope of and applications of C-H activation in construction of complex structures.Chapter four, Rh (Ⅲ)-catalyzed C-H alkynylation of azomethine ylides under mild conditionsRh (Ⅲ)-catalyzed efficient C-H alkynylation of azomethines with alkynylated hypervalent iodine is developed under mild conditions. We have established a broad scope of azomethine substrates with high efficiency for azomethines bearing various aryl and heteroaryl rings. Moreover, this coupling reaction can provide a method for the ortho C-H alkynylation of aryl aldehydes, which may find application in the synthesis of related structures.Chapter five, Conclusion and Prospect...