Construction Of Indole And Isoquinoline Via Visible-Light Photoredox Catalysis

Aromatic heterocyclic compounds are widely found in natural products and pharmaceutical molecules with important physiological activities.Therefore,the development of green and efficient methods for the construction of aromatic heterocyclic compounds is of great significance in the field of organic synthesis and pharmaceutical chemistry.We aim at the efficient synthesis of indoles and isoquinolines by photoredox catalytic reactions.Ultraviolet light is high energy and harmful to human body.In addition,organic reactions promoted by UV light often require the special and expensive experimental device,such as high-pressure mercury lamp,and the scale of the reaction often is limited by the size of the reaction vessel,which hinders the applications of UV light in organic synthesis.Visible light has the highest content in the solar light,accounting for 46%.It has the characteristics of high natural abundance,simple use,great application potential,which makes visible light catalysis a powerful means of organic synthesis.In recent years,the vigorous development of visible light photoredox catalysis also has provided a bright light for the efficient generation of free radicals.The effective synthesis of nitrogen-containing heterocyclic compounds has been a forward position field of organic chemistry research.Then,how to efficiently synthesize nitrogen-containing heterocyclic compounds such as indole,quinoline and isoquinoline under mild conditions is the research goal of organic chemists.Therefore,we try to use visible light to promote the redox reaction in order to achieve the efficient synthesis of indoles and isoquinolines.The first part of this dissertation describes the synthesis of indole compounds.We use[Ir(dF(CF3)ppy)2(bpy)]PF6 as a photosensitizer and PIDA as an oxidant under visible light irradiation.N-C and C-C bonds are formed via amidyl radicals and after aromatization,indole compounds are given.In the experimental part,the mechanism was verified.The reaction is realized by the single electron transfer of oxidizer as the quencher of the excited photosensitizer.The second part of this dissertation discusses the synthesis of isoquinoline compounds.We use benzophenone-derived imine as an imine radical precursor.The synthesis of isoquinoline is realized by the radical cyclization with diphenylacetylene intermolecularly.In the experimental part,the mechanism was verified.It is supposed that the reaction is realized by the single electron transfer of benzophenone imide as the quencher of the excited photosensitizer.