The Cascade Reaction Of Photo/Electro Induced Methoxy Radical And Benzene Radical

Both visible light photoredox catalysis(PRC)and synthetic electrochemistry(SOE)produce active free radical or radical ions through a single electron transfer process(SET).PRC reactions use“photons”as a reaction reagent and SOC reactions select“electrons”as a cleaning reagent in both research areas.Because of the similar modes of action,many transformations have been translated from electrochemical to photoredox methodology and vice versa.However,PRC and SOE are often thought of as competing technologies.The photoelectrochemical organic synthesis strategy has unique advantages in chemical transformations.A series of examples show that the photoelectrochemical organic synthesis reaction can achieve some reactions that are difficult to achieve with a single photochemical or electrochemical method.In addition,the photoelectrochemical organic synthesis strategy has unique advantages and conforms to the development concept of green chemistry and atomic economy.In this paper,a new method for the generation of Me O·under the condition of cerium catalyzed photoelectrochemistry was developed.This method is characterized by mild conditions,low oxidation potential and good tolerance of functional groups.In this process,Ce(IV)was formed by oxidizing Ce(III)at the surface of anode at a low potential,and then combined with methanol to form Ce(IV)-OMe complex,which forms Me O·by ligand metal charge transfer mechanism under light condition.Me O·selectively activated Si(sp~3)-H bonds in silanes instead of C(sp~3)-H bonds in alkanes and C(sp~3)-H bonds in alkanes.The silicon radicals and alkyl radicals produced by hydrogen transfer mechanism reacted in series to form silicon or alkyl substituted benzimidazo isoquinolinones.In addition,a mild and simple method for the synthesis of aryl substituted quinoxalinones,benzothiophenes and phenanthrenes was developed.The arylation reaction was realized by using paired electrosynthesis technology and the mechanism of aryl reaction was determined by a series of control experiments.The paper conducted the following research:1)Using photoelectrochemical catalytic synthesis method,with cerium salt as electrocatalyst,Me OH as HAT reagent,the Ce(IV)-Me O·metal complex was generated by the combination of Me OH and Ce(IV)oxidized under surface of anode.And then Me O radical was induced by ligand metal charge transfer(LMCT)of the metal complex under irradiation light.The Me O·,as a HAT reagent,attract hydrogen atom in inactive Si(sp~3)-H to induce silicon-based free radical.A series reaction of silicon radical with N-methylacrylamide was carried out to obtain silicon inserted benzimidazo quinoxalinones.In this reaction process,the effects of electrode materials,current density,the amount of methanol as a HAT reagent,solvent and wavelength of light,cerium salt catalyst,methanol,light source and current on the reaction were explored.A new cross coupling reaction method for the synthesis of silyl substituted benzimidazoloquinoxalinones via LMCT pathway catalyzed by cerium salt was established.The scope of the reaction was investigated,and the mechanism of the reaction was determined by a series of controlling experiments.2)On the basis of the first part of the research,we also use the photochemical catalytic synthesis method to produce Me O·,and the Me O·as a HAT reagent,attract hydrogen atom in inactive C(sp~3)-H to induce carbon-based free radical.A series reaction of silicon radical with N-methylacrylamide was carried out to obtain alkyl inserted benzimidazo quinoxalinones.In this reaction process,the effects of types of HAT reagent,catalysts,supporting electrolytes,electrode materials time on reaction,current density and wavelength of light,cerium salt catalyst,methanol,light source and current on the reaction were explored.A new photoelectrochemical organic cross coupling reaction synthesis strategy for the synthesis of alkyl substituted benzimidazoloquinoxalinones via LMCT pathway catalyzed by cerium salt was established.The scope of the reaction was investigated,and the mechanism of the reaction was determined by a series of controlling experiments.3)The generation of aryl radicals induced by electrochemical reduction was studied,and the Minisci arylation of electron deficient heterocycles was realized by paired electrosynthesis.In the electrochemical reaction,the effects of solvent,supporting electrolyte,electrode material and current density on the reaction were explored.A Minisci arylation reaction via a paired electrosynthesis was developed.The scope of the reaction substrate was investigated and the scale-up experiment by circulation pump type was carried out.The mechanism of the electrochemical reaction was determined by a series of control experiments and CV experiments.In addition,by comparing photochemical and electrochemical Minisci arylation reactions,it is confirmed that photochemical arylation can also be realized under electrochemical conditions.4)Furthermore,benzene radicals induced by cathodic reduction were applied to the series reaction of electron-rich alkynes.In the electrochemical reaction,the influence factors such as solvent,supporting electrolyte,electrode material and current density on the reaction were studied.An electrochemical method of synthesizing benzothiophene and phenanthrene compounds was established via a paired electrolysis.The scope of the reaction was investigated and confirmed that the reaction had good substrate universality.