Functionalization Of Sp²-carbon Atoms Via Visible-light Photoredox Catalysis With CHCl₃

Photorecox catalysis is a strategy that used visible light as an energy source,which is simple operation and mild conditions,and has been widely concerned by organic chemists in recent years.The chlorine-containing functional groups were encountered in various important molecules,but how to accurately and gently introduce chlorine-containing functional groups is still challenging.Therefore,it is of great significance to develop economical,simple and easily available free radical sources and efficient synthesis strategies.Chloroform（CHCl₃）is an inexpensive and readily available solvent and it was proved to be an important precursor of various chlorine-containing functional groups.Under photorecox catalysis conditions,chlorine-containing free radicals can be generated via hydrogen atom transfer（HAT）or chlorine atom transfer（CAT）,which could then add to alkenes or aromatic rings,to realize the functionalization of various sp² carbons.In this dissertation,chloroform（or deuterium chloroform）was unprecedented used as the reaction reagent and medium as well,to achieve the the defluorinated dichloromethylation ofα-trifluoromethyl olefin,C3-chlorination and C3-trideuterium methylation of quinoxalinone,under visible-light induced photoredox catalysis conditions,which is featured with high selectivity,and has potential applications in industry.All the chapters focused on different aspects of the total problem as follows:（1）Chloroform was used as dichloromethyl source,to realize the defluorinated dichloromethylation reaction ofα-trifluoromethyl olefin was achieved under visible light driven,with Ir[d F（CF₃）ppy]₂（dtbpy）PF₆as catalyst.A series of 1,1-difluoro-2-aryl-3-dichloromethyl propylene derivatives are obtained with moderate to good yields.In addition,deuterated chloroform can be used as solvent to synthesize 1,1-difluoro-3-deuterated dichloromethyl propylene compound with high efficiency,deuterium substitution rate up to 99%.（2）Chloroform was used as chlorine source to achieve chlorination of heterarene for the first time under visible light induced,with Ir[d F（CF₃）ppy]₂（4,4’-d CF₃bpy）PF₆ as catalyst.This method provides a new idea for developing a new chlorination strategy.Different substituents of quinoxalinone have good functional group tolerance and moderate to good yield.In addition,other nitrogen heterocyclic rings,such as imidazolidazine,can also be synthesized by this method.The formed intermediate can achieve the efficient synthesis of a series of quinoxalinone C3-chlorides through the CAT and SET processes.The obtained chlorinated products can be further derivatized into amide and amide ester derivatives,providing an efficient synthetic strategy for synthesizing a large number of value-added amine compounds.（3）The C3-trideuterium methylation of quinoxalinone was achieved for the first time by using deuterium chloroform as trideuterium methyl source.This method has good substrate tolerance,good yield and high deuterium substitution to the benzene ring and N1-substituted group of quinoxalinone.This method has a good application prospect and provides a useful strategy for the synthesis of other deuterated compounds.