Palladium And Copper Catalyzed C-C/C-X Bond Formation

The transition-metal catalyzed C-C/C-X bond coupling reaction is a hotspot in modern organic synthesis. The application of transition-metal catalyzed small organic molecules C-C/C-X bond formation is contribute to both the theory of organic chemistry development and the chemical industry application. In this research, we systematically reviewd the research development in transition-metal catalyzed C-C bond coupling and C-N bond coupling, and then presented our research on the transition-metal catalyzed C-H activation/C-C cross coupling or the direct C-X(X=N,O) formation via C-H activation. The details are summarized as followes:1. Mild conditions have been developed to achieve the Pd(OAc)2-catalyzed intramolecular C-H activation/C-C cross coupling within N,N-diphenyl-acetamides in good to high yields in acetic acid. This method allows the efficient formation of differently substituted carbazoles. In this cross-dehydrogenative coupling, many different functional groups are tolerated and the starting material N,N-diphenyl-acetamides can be easily prepared in one step from commercially available acetanilides and iodobenzenes. A mechanism for this catalytic reaction was proposed.2. A highly efficient amidation reaction of heterocycles with N-Fluorobenzenesulfonimide(NFSI) has been developed, presumably proceeding via C-H bond activation. Cuprous iodide was employed as the catalyst, and various a-amidated heterocycle derivatives have been generated in good to excellent yields. This chemistry endowed an economic method of synthesis valuable amidated heterocycles through a direct C-N bond coupling processes. A mechanism for this catalytic reaction was proposed.3. An efficient copper-catalyzed direct imidation of C(sp3)-H bonds adjacent to sulfur atoms of thioanisoles has been developed under mild condition. The can be reused with high efficiency. A mechanism for this catalytic reaction was proposed. The use of nitrogen ligands was avoied in this catalytic system.4. A highly efficient acetoxylation reaction of N-aryl-arylsulfonamides has been developed, presumably proceeding via the selective functionalization of N-aryl C-H bonds. A stoichiometric amount of PhI(OAc)2 was generally employed as the oxidation reagent, and various para-acetoxylated sulfonamide derivatives had been generated in excellent yields. This chemistry endowed an economic synthesis of valuable acetoxylated sulfonamides through direct C-O bond formation processes. A mechanism for this reaction was proposed.