C2,C3-cyclization Dearomatization And Oxidative Ring Expansion Reaction Of Indoles

In this thesis,we mainly study the construction of heterocyclic compounds via cyclization and ring expansion reaction of indoles under mild conditions.The whole work is constituted by four parts as follow:In the first part,an efficient metal-free dearomatization of indoles with ?-bromohydrazones is studied.A systematic study on electronic and steric effects of substrate and reagents revealed that they have great influence upon the reaction.In the second part,I2/TBPB mediated oxidative reaction of N-tosylhydrazones with indoles is studied.It provides an environmentally friendly and atom-economy strategy for the construction of indoline compounds.In the third part,novel and efficient synthesis of eight-membered nitrogen heterocycles in one pot by copper-catalyzed oxidative ring expansion and intermolecular cyclization sequencing of indoles with amidines has been sdudied.A variety of valuable benzo[1,3,5]triazocin-6(5H)-one derivatives bearing functional groups were assembled in mild conditions.In the fourth part,a new route for the preparation of benzo[1,5]diazocines from indoles and enaminone analogues is described.In addition,a plausible mechanism involving a cascade of copper-catalyzed oxidation/intermolecular cyclization/oxygen-participated intramolecular ring-opening is suggested.