Construction And Functionalization Of N-Containing Heterocycles Via Photo/Electrochemistry

N-Containing heterocyclic compounds are widely used in medicine,pesticides,materials,energy and biological.Therefore,it is very meaningful to develop various convenient,efficient and green methods to realize the synthesis of N-Containing heterocyclic compounds.The construction of C-N bonds and the functionalization of N-Containing heterocycles are two effective strategies for the construction of NContaining heterocycles.With the proposal of green sustainable development strategy,the direct oxidative cross-coupling of two hydrocarbons was developed in order to avoid the prefunctionalization of substrates and make the synthesis strategy more green.In recent years,with the development of photochemistry and electrochemistry,the strategy of using photochemistry or electrochemistry to realize the synthesis of highvalue compounds,which can convert green light energy and electric energy into chemical energy,provides two ideas for organic synthetic chemistry.Firstly,this paper summarizes the development of the construction of NContaining heterocyclic compounds through the functionalization of N-H compounds in recent years.According to the different activation modes,this paper discusses the research process and current situation of constructing N-Containing heterocycles by transition metal catalyzed functionalization of N-H compounds,functionalization of NH compounds by nitrogen free radicals,functionalization of N-H compounds induced by photochemistry and functionalization of N-H compounds induced by electrochemistry.Then,taking Minisci reaction as an example,the development process and current situation of the construction of N-Containing heterocycles through the functionalization of N-Containing heterocycles are introduced.The research content of this paper is mainly to realize the alkylation of isoquinoline compounds by photoinduced strategy,the functionalization of caffeine and the construction of oxazoline compounds by electrochemical strategy.The development of mild and efficient strategies to activate small molecules such as methane and ethane to realize the methylation and ethylation of nitrogen heterocyclic compounds,and the development of mild and efficient strategies to realize the conversion of more cheap organics into high-value N-Containing heterocyclic compounds is one of the development trends in this field.The main research results of this paper are as follows:1.In this paper,it is studied that the selectfluor can produce the homolysis of N-F bond and produce nitrogen radical under the condition of visible light.It can be used as a hydrogen transfer reagent,which can effectively activate the C-H bond of simple alkanes and realize the alkylation of N-Containing heterocyclic compounds.A series of alkane were suitable in this reaction with high yield.In the mechanistic study,the generation of nitrogen radical is verified by EPR,and a new activation mode of selectfluor is proposed.2.In this paper,the electrochemical strategy for activation of caffeine is studied.Pyrazole and other functional reagents are used as functional reagents to realize the selective functionalization of caffeine.The functionalization of caffeine via electrochemical strategy,which avoids the application of equivalent oxidant,has high atomic utilization and economic effect.In this reaction system,the oxidation potential of reactants can be controlled by the solvent,which can realize the selective functionalization of C2 position of caffeine and the selective dearomatization functionalization of caffeine.3.In this paper,it is proposed that 1,2-dichloroethane can produce chloride anion under electrochemical conditions,and then the chloride anion is oxidized at the anode and reacts with olefins to form chloronium species.Subsequently,the intermediate of chloronium species are captured by benzamides,realizing the cyclization of cheap olefins and amides to construct high-value oxazoline compounds.Various mechanism experiments have proved the existence of chloronium species,which provides a new strategy for electrochemical activation of olefins.