Trifluoromethylation Reactions Of N-acylhydrazones And Allylic Oximes

The trifluoromethyl group is the most prevalent fluorine-containing group in fluorine drugs,agrochemicals and materials due to the fact that the trifluoromethyl group often improves the metabolic stability and lipophilicity of biologically active compounds over their non-fluorinated analogues.Therefore,it is not surprising that many efforts have been devoted to the incorporation of the CF₃ group organic compounds.To date,a series of trifluoromethylating reagents have been developed,inculding Umemoto's reagent,Langlois/Baran's reagents,CF₃I,Ruppert–Prakash's reagent?Me₃SiCF₃?,Togni's reagent etc.TMSCF₃ is a relatively inexpensive and stable trifluoromethylated reagent,which plays an important role in the study of trifluoromethylation.We have demonstrated the trifluoromethylation of N-acylhydrazones and allylic oximes by using TMSCF₃ as the CF₃ source in this paper.The paper consists of three parts:Thechapterone:ResearchProgressofTMSCF₃Participated Trifluoromethylation ReactionsIn this chapter,the research progress ofTMSCF₃ participated trifluoromethylation is mainly introducted from two aspects.The first aspect,TMSCF₃ involved in the nucleophilic trifluoromethylation reaction.The second aspect,TMSCF₃ participated oxidative trifluoromethylation,which include oxidative trifluoromethylation under metal-free conditions and transition-metal-mediated or-catalyzed oxidative trifluoromethylation.The chapter two:Phenyliodonium diacetate mediated carbotrifluoromethylation of N-acylhydrazonesWe have firstly demonstrated the carbotrifluoromethylation of N-acylhydrazones using the combination of inexpensive,stable and commercially available TMSCF₃and PhI?OAc?₂ as the CF₃ source under mild reaction conditions.This method provides a convenient and efficient procedure for the synthesis of trifluoromethylated N-acylhydrazonesfromaldehyde-derivedN-acylhydrazones.Thehighly functionalized trifluoromethylated N-acylhydrazones can be used as trifluoromethyl synthetic building blocks for further transformations to other valuable trifluoromethyl compounds.Thechapterthree:TrichloroisocyanuricAcidPromotedCascade Cyclization/Trifluoromethylation of Allylic OximesCheap and commercially available trichloroisocyanuric acid has been used to promote the first trifluoromethylation by using TMSCF₃ as the CF₃ source.Allylic oximes were efficiently converted to trifluoromethylated 4,5-dihydroisoxazoles in good to excellent yields by cascade cyclization/trifluoromethylation.The related products,trifluoromethyl-containing 4,5-dihydroisoxazoles,could be easily converted into 1,3-amino alcohol and?-hydroxy ketone by reductive ring-opening reactions.