Study On Hydrogen Transfer-Mediated Multicomponent Cyclization Of Azaarene Salts

N-heterocyclic compounds are a very important class of organic compounds,which are widely used in the fields of natural products,biology,medicine,ligands,dyes,functional materials.In addition,aromatic amines and formaldehyde are basic chemical raw materials,they are indispensable substance resources for national economy and the sustainable development of society.Therefore,the development of a new and efficient multi-component coupling approaches to realize the construction of new functional N-heterocycles and produce valued-added products that meet the needs of human being from aromatic amines and aldehydes is of important significance is an important research subject.Through ruthenium-catalyzed hydrogen transfer-activated strategy for N-heteroarenium salts,this thesis describes the development of two direct annulation reactions for the construction of fused new Nheterocycles,and the content is divided into the following three sections:(1)The first chapter is the introduction section.The basic situation of N-heterocyclic compounds is summarized,the multi-component reaction of nitrogen-containing compounds is briefly introduced according to the classification of nitrogen source,and the domestic and foreign research of N-heterocyclic compounds ranging from hydrogenation reaction to hydrogen transfer coupling reaction is systematically sumarrized.(2)The second chapter is ruthenium-catalyzed hydrogen transfer-mediated multicomponent cyclization reaction of quinoline salt.It is shown that under the catalysis of ruthenium,the azaarene salt forms in situ the active intermediates of imine or enamine which are beneficial to the coupling process,which are then captured by the condensed intermediates from arylamines and paraformaldehyde,and form the fused N-heterocyclic products.The developed catalytic system proceeds with operational simplicity,mild conditions,broad substrate and good functional group compatibility.It provides an important basis for the selective synthesis of fused functional N-heterocyclic molecules from simple and readily available multi-component raw materials.(3)The third chapter is ruthenium-catalyzed hydrogen transfer-mediated multi-component cyclization reaction of isoquinoline salt.Through a ruthenium-catalyzed hydrogen transfer strategy,the multi-component tandem methylation and cyclization reaction of isoquinoline salts with aromatic amines and paraformaldehyde was realized.The reaction demonstrates braod substrate scope and good functional group compatibility,and affords the fused N-heterocyclic products with excellent chemo-and stereo-selectivity.The present work has offered an important basis for further discovery of functional molecules including bioactive ones.In summary,through ruthenium-catalyzed hydrogen transfer-mediated cyclization strategy,the work presented in this thesis has developed two multi-component reactions with broad substrate scope,good functional group compatibility,operational simplicity,and mild conditions.The two reactions allows to efficiently construct functional fused N-heterocycles from simple and readily available raw materials,which provides new conceptions for the chemical transformation and structural modification of inert azaarenes,and enriches the connotation of organic synthetic methodology.