Oxidative C-H Functionalization And The Application In Cascade Cyclization Reaction

Formation of new C-X (X=C, O, N, etc.) bonds by direct C-H activation is an important research topic for chemists. It is not only owing to its atom economy and environmental benefits, but also because it shows more potential of chemical reactions. Generally, oxidative addition of precious metals is often required in C-H activation. In the past decade, C-H functionalization which is realized through single-electron-transfer process, has attracted increasing interest among chemists. Most of them are catalyzed by cheap and low-toxic copper salts, iron salts, or not. Therefore, C-H functionalization should have more practical value.On the other hand, cascade reactions avoid the step by step separations and purifications of intermediates and reduce the amount of pollutant waste. Thence, the cascade cyclizations involving C-H functionalization are the focus of our recent research, and they are also the core contents of my dissertation.This dissertation mainly contains the following sections.The first chapter is a review of functionalization of sp3 C-H bond and sp2 C-H bond, involving three parts:intermolecular coupling, intramolecular cyclization and cascade cyclization.The second, third and fouth chapters are about the sp3 C-H functionalization. In the second chapter, we introduce a cascade cyclization of multiple sp3 C-H functionalizations in one pot, catalyzed by FeCl3. This reaction starts from simple molecules, and forms complex ring-fused heterocyclic compound by two C-C bonds and one C-N bond formation as well as one C-N bond cleavage, that shows great novelty. In the third chapter, we introduce a sp3 C-H amination. In this reaction, the arylamines were the substrate. Compared with amides and azoles, arylamines have more challenging. In the fouth chapter, we introduce a a-vinylation of amides with arylacetylenes under metal-free conditions. Generally, the addition reaction of sp3 C-H bond with sp C-C bond should be catalyzed by metal in the way of cis-addition, and the main product is trans-isomer. Our reaction is just the opposite of all. Unfortunately, theproducts in the third and fouth chapters did not realized the further cyclization.The fifth chapter is about the sp2 C-H functionalization. This reaction starts from amidines, and realizes the cascade process of Pd-catalyzed N-arylation and Cu-catalyzed C-H functionalization/C-N bond formation in one pot.The sixth chapter introduce an intramolecular double sp2 C-H activations between the 2-position of imidazole and a benzene ring catalyzed by Palladium(II). Unfortunately, the one-pot reaction with the nucleophilic substitution of (Z)-(2-bromovinyl) benzene and 1H-azole catalyzed by FeCl3 is not completed.The seventh chapter is about the double activations of C-C bond and C-H bond. This reaction is a deacetophenonylative arylation reaction, catalyzed cooperatively by transition metal and Lewis acid. The way of Ca-Cp bond activation in unstrained ketone is very novel.