Rh(Ⅲ)-Catalyzed Heterocycle Synthesis Via C-H Bond Activation

Presently, transition metal-catalyzed C-H functionalization has been becoming an efficient strategy for the formation of C-C and C-X bond in organic synthesis. Heterocyclic compounds are important structural motif existing in natural products and pharmaceuticals. This thesis first introduces Rh(Ⅲ)-catalyzed heterocycle synthesis via C-H bond activation such as reactions with alkenes, alkynes, aldehydes and nitrogen compounds. Inspired by these studies, we mainly focused on the synthesis of heterocyclic compounds catalyzed by rhodium. The main researches are as follows:We have developed the Rh(Ⅲ)-catalyzed ortho C-H bond olefination of aryl sulfonamide directed by SO2NHAc group. The reactions of N-tosylacetamide with acrylate esters afford ortho-alkenlated benzofused five-membered cyclic sulfonamides, whereas with styrenes provide the direct diolefination products. This oxidative coupling process is achieved in high efficiency and selectively with a broad substrate scope. The reaction tolerates a variety of important functional group. It is an efficient method for the synthesis of aryl sultams, an aore structures in pharmacologically active substances, through derivatization.We have achieved an efficient methodology for the synthesis of isoquinolones from Benzylidene-(3-methyl-pyridin-2-yl)-amine and alkynes using Rh(Ⅲ) as the catalyst. The catalytic reaction had many advantages, such as wide substrate scope, highly selectivity and efficiency. Notably, this reaction condition could be also applied to an efficient one-pot synthesis of isoquinolones by three-component reaction of benzaldehyde, amine, and alkynes. The catalytic reaction possibly via a double C-H bond activation process provided an efficient method for the synthesis of isoquinolones.