Studies On Transition-metal-catalyzed C-h Functionalization

Selective C-H bond functionalization has been the dream of the organic chemist for a long time. Because the bond energy of C-H is up to 414 kJ/mol, it present the inert in the reaction. Therefore, the C-H bond functionalization is called as"bible"in the organic chemistry. This dissertation consists of three parts. (1) The recent advances in C-H bond functionalization were reviewed. (2) Palladium-catalyzed acylation of sp2 C-H bond. (3) Palladium-catalyzed cyanation of sp2 C-H bond.In part one the recents advances in C-H bond functionalization were reviewed, includidng the formation of C-C,C-X,C-O,C-N and so on via C-H activation. In part two palladium-catalyzed regioselective acylations of aromatic C-H bonds using aldehydes in the presence of air as the ideal oxidant was described and investigated the tentative reaction mechanism. In part three transition-metal-catalyzed direct cyanation of sp2 C-H Bonds was explored. (1) The palladium-catalyzed ortho-cyanation of aromatic C-H bonds employing CuCN as a cyanating reagent was described. (2) The chelation-assisted palladium-catalyzed cascade bromination/cyanation of 2-arylpyridine and 1-arylpyrazole C-H bonds employing K3[Fe(CN)6] as a nontoxic and safe cyanating reagent was described.In conclusion, we have demonstrated palladium-catalyzed acylation and cyanation of sp2 C-H bond which enjoying the advantages of mild reaction conditions, simple operation, and commercially available materials. Importantly, There reaction represents a convenient and atom economic method for the synthesis of diaryl ketone derivatives and aromatic nitriles.