Study On Photocatalyzed Radical Fluoroalkylations For The Synthesis Of Fluoroalkylated N-Heterocyclic Compounds

Recently,the development of eco-friendly radical processes has become of great interest in synthetic chemistry.In particular,visible-light photocatalysis has drawn tremendousattention for its environmental compatibility and versatility in promoting many synthetically important reactions.Since adding fluoroalkyl groups can dramatically change the physical and chemical properties of organic compounds,using these processes to promote eco-friendly radical fluoroalkylations will have a major impact in areas such as pharmaceuticals,agrochemicals,and material sciences.In this thesis,the reaction of difluoromethylation and trifluoroethylation under photocatalysis were studied:First,the visible-light-induced oxydifluoromethylation of olefinic amides with difluoromethyl sulfones using cyclometalated iridium(III)complexes as photocatalysts has been explored.This method allows for an efficient and practical synthesis of a variety of CF2H-containing benzoxazines and oxazolines bearing various functional groups under mild conditions.We gave the possible reaction mechanism of visible light-induced difluoromethylation.And a series of benzoxazine and oxazoline compounds were analyzed by NMR,mass spectrometry.Some of the compounds were determined by X-ray diffraction.Second,a visible-light-induced C-3 selective trifluoroethylation of imidazoheterocycles using 1,1,1-trifluoro-2-iodoethane and fac-Ir(III)(ppy)3 as trifluoroethyl radical sources and photocatalyst was developed.The methodology enables the introduction of a trifluoroethyl group in a fast and efficient reaction under mid conditions with high functional group tolerance.And we also gave the possible reaction mechanism of visible light-induced difluoromethylation.At last,a series of benzoxazine and oxazoline compounds were analyzed by NMR,mass spectrometry.Some of the compounds were determined by X-ray diffraction.