Studies On The Noval Synthesis Of Difluoroalkylated Oxazolidine-2-imine And Preparation Of ?,?,?,?-tetrafluoro-?-hydroxy Ketone And ?-fluoroacetophenone

Organic fluorine compounds are widely used in various fields,including agricultural chemistry,medicinal chemistry,and materials science.The development of efficient and novel methods to synthesize organofluorine compounds has become a hot topic in organic chemistry.The work of this thesis mainly focused on:1)The synthesis of difluoromethyl-substituted oxazolidine-2-imine via visible light promoted catalysis.2)The synthesis of?,?,?,?-tetrafluoro-?-hydroxyketone and?-fluoroacetophenone from diphenly-1,3-propanedione through the modification of reaction conditions.The specific content includes the following three points:The first chapter is review.The visible light-mediated catalytic system,reaction mechanism,general reaction mode and common visible light catalysts were introduced at first.Then,the research progress of fluoroalkylation according to the different types of substrates was reviewed with a sequence of sp hybrid carbon?alkyne and isocyanide?,sp² hybrid carbon?olefin and aryl?,sp³ hybrid carbon?alkane?and hydroxyl,thiol group.The second chapter described the synthesis of difluoromethylated oxazolidine-2-imines via visible light-promoted three-component tandem reaction.Taken allylamine,isocyanate as substrates,2-BTSO₂CF₂H as CF₂H radical source,a visible light-induced three-component tandem reaction was performed to get difluoromethylated oxazolidine-2-imine in good yield.The free radical capture and fluorescence quenching experiments confirmed the addition of free radicals to olefins and the tandem cyclization mechanism.The third chapter was written to report two types of molecules which were prepared through mono-,di-fluoro of 1,3-diaryl-1,3-propanedione with different reaction conditions.The 2,2-difluoro-1,3-diaryl-1,3-propanedione,which was difluorinated by1,3-diaryl-1,3-propanedione,reacted with cesium carbonate to produce?,?,?,?-tetrafluoro-?-hydroxy-ketone.Mono-fluorinated 1,3-diaryl-1,3-propanedione can transform to?-fluoroacetophenone in the presence of cesium carbonate.