Study On The Construction Of Nitrogen-containing Heterocycles Via Oxidative C–H Amination And Cyclization Of Diarylamines

Nitrogen-containing molecules are widely present in natural products,pharmaceutical preparations,and functional materials,which has prompted scientists to continuously strive to develop more efficient amination methods.C–H amination of hydrocarbon compounds without need for pre-installation of active groups and provides a powerful way to achieve the construction of nitrogen-containing molecules?especially nitrogen-containing heterocycles?.In this thesis,through the single electron oxidation mediated tandem C–H amination strategy under Cu/O₂ catalyst system,diarylamines and different nucleophiles?including free primary amines,secondary amines,1,3-dicarbonyl compounds and indoles?as reaction substrates,the study has explored the methods combining C–H amination with cyclization,four types of functionalized nitrogen-containing heterocycles with potential applications,including benzimidazoles,benzimidazolones,indoles and indolo[2,3-b]indoles,have been successfully and efficiently constructed.The details are as follows:?1?In chapter 2,through copper-catalyzed single electron oxidation mediated tandem triple C-H aminations with free amines as the aminating agents,we herein present a precedent on copper-catalyzed synthesis of 5-diarylamino benzimidazoles,a class of optoelectronic device analogues by combining two molecules of diarylamines and one molecule of alkylamine in one single operation.The developed chemistry proceeds with the merits of a natural abundant Cu/O₂ catalyst system,readily available feedstocks,broad substrate scope,good functional group tolerance,exclusive regio-and chemo-selectivity,high step and atom efficiency,which offers an important basis for further construction of functional products by employing tandem C-H amination strategy.?2?In chapter 3,we present a multicomponent synthesis of functional benzimidazolones from arylamines,dialkylamines,and alcohols,acting via the sequence of copper-catalyzed single electron oxidation mediated tandem C–H aminations and alkyl deconstructive carbofunctionalization.The catalytic transformation avoids pre-installation of aminating agents and directing groups,resulting in direct functionalization of inert C–H and C–C bonds.This platform can be expected to provide structurally diverse complex molecules.?3?In chapter 4,a tandem C–H bond amination of diarylamines and 2-substituted cyclic amines and selective C–C bonds and C–N deconstructive functionalization of cyclic amines was developed via copper-catalyzed single electron oxidation mediated C–H amination,thereby directly constructing 5,6-diaminobenzimidazoles.This method providing a practical method for the synthesis of complex functionalized molecules that are difficult to prepare with existing strategies.?4?In chapter 5,under copper catalysis,an unprecedented direct synthesis of functionalized indoles via single electron oxidation mediated tandem C–H aminations of diarylamines with 1,3-dicarbonyl compounds is presented.This strategy can build multiple chemical bonds in one single operation,and offer the possibility for the further introduction of functional groups to build more complex indole skeleton molecules.?5?In chapter 6,an unprecedented copper-catalyzed single electron oxidation mediated tandem C–H aminations and[3+2]annulation of diarylamines with indoles was developed,which allows direct access to novel 2-diarylaminoindolo[2,3-b]indoles,a class of potential photoelectric device molecules.This strategy provides a practical reference for the construction of functionalized poly nitrogen-containing heterocycles in one operation.