Difluoroalkylation Reactions Via Single Electron Transfer Process

Difluorinated molecules with the unique physiological activity and physicochemical properties,are widely used in pharmaceuticals,agrochemicals and advanced functional materials.Recently,transition-metal-catalyzed difluoroalkylation reactions have been greatly developed,which are mostly only applicable to primary,secondary alkyl and aryl substrates.Based on the pioneering studies,we sought to develop new methods to prepare difluorinated compounds through single-electrontransfer(SET)path way.I:Photoredox-catalyzed decarboxylative difluoroalkylation of alkyl carboxylic redox esters.In this chapter,a general method for difluoroalkylation of alkyl carboxylic redox esters with difluoroenoxysilanes through photoredox-catalyzed decarboxylative reaction has been developed.The reaction can also be extended to aliphatic amine derived pyridinium salts and provided the α,α-difluoroalkyl ketone.This method has the advantages of high efficiency,mild reaction conditions,and broad substrate scope,including primary,secondary,and sterically hindered tertiaryl alkyl substrates.Although the transition-metal-catalyzed difluoroalkylation represents a modern strategy to prepare fluorinated compounds,the difluoromethylation of tertiary alkyl remains a challenging topic.The current process can overcome this limitation,thus featuring the advantages of this method.Ⅱ:N-Heterocyclic Carbene-catalyzed acyldifluoroalkylation of alkenes.In this chapter,we report the acyldifluoroalkylation of a variety of olefins through N-heterocyclic carbene organocatalysis.The method can be applied to a variety of aryl alkenes as well as commercially available aryl aldehydes and BrCF2COOEt.The reaction proceeds under mild reaction conditions with hight efficiency and excellent regiochemical selectivity,thus paving a new way in the preparation of difluorinated compounds.