N-containing Group Directing ?-C-H Functionalization/Cyclization Reactions

N-Heterocyclic compounds are one of the most important classes of organic compouds which play a nonnegligible role both in biological and industrial fields.Therefore,organic chemists have been making extensive efforts to produce these N-heterocyclic compounds by developing new and efficient synthetic transformations.Among a variety of new synthetic transformations,transition-metal-catalyzed reactions are some of the most attractive methodologies for synthesizing them.In this paper,Rh(?)-catalyzed N-heterocycle synthesis via cascade C-H functionalization/cyclization reaction are developed.Meanwhile,related research backgrounds are introduced.The dissertation mainly contains the following sections.The first chapter is a mini review of N-containing group directing ?-C-H functionalization/cyclization reactions.Different directing groups like amide,amine,imine,N-heterocycles etc.are systematacially classified and discussed.The second chapter is a novel cascade ?-C-H functionalization/cyclization reaction of N-carbamoyl indoles with ?-halo,?-mesyl or ?-tosyl ketones under rhodium(?)catalysis,which affording desired dihydropyrimido[1,6-?]indolone derivatives in moderate to excellent yields.The reaction condition is mild and simple,and the desired product can be easily turned to pyrimido[1,6-?]indolone in the presence of acid.Moreover,a plausible mechanism utilizing N-carbamoyl group in N-carbamoyl indoles to direct ?-C-H functionalization was also postulated for the cascade reaction.The third chapter is a cascade ?-C-H functionalization/cyclization reaction of N-arylpyridin-2-amines with ?,?-unsaturated aldehydes for the synthesis of dihydroquinolinone derivatives under rhodium catalysis.Various electron-withdrawing or electron-donating functional groups on the benzene rings of N-arylpyridin-2-amines are compatible to the cascade reaction,producing dihydroquinolinone derivatives in moderate to excellent yields.The catalytic cascade reaction proceeds under mild conditions,uses air as an oxidant,and the main byproduct is H2O.A plausible mechanism of dual catalytic cycles by rhodium(?)catalysis is also proposed.The forth chapter is an unprecedented DCC reaction between chromene and aldehydes catalyzed by proline has been developed via direct ?-C-H functionalization.Various aldehydes were able to react smoothly with chromene using DDQ as an oxidant.A plausible mechanism using DDQ to activate ?-C-H of chromene and proline to activate aldehyde is also proposed.