The Study Of Palladium Catalyzed Carboheterofunctionalization Reaction Of Unsaturated Hydrocarbons | Posted on:2024-01-05 | Degree:Master | Type:Thesis | Country:China | Candidate:S T Zhang | Full Text:PDF | GTID:2531306917953299 | Subject:Chemistry | Abstract/Summary: | PDF Full Text Request | Palladium catalyzed cyclization of unsaturated hydrocarbon is a kind of very important organic chemical reaction,which can transform important precursor compounds of unsaturated hydrocarbon into a variety of heterocyclic compounds with biological activity.In this field,palladium catalyzed carboamination/carboetherification of unsaturated hydrocarbon and organic halides can easily and efficiently synthesize heterocyclic compounds by simultaneously building C-C bonds,C-N and C-O bonds in one step.Therefore,it is of great significance to develop new electrophilic reagents to participate in palladium catalyzed heterofunctionalization of unsaturated hydrocarbon to synthesize heterocyclic compounds.This dissertation focuses on the palladium catalyzed heterofunctionalization of unsaturated hydrocarbon to form new strategies for heterocyclic compounds.The research mainly includes three aspects of content.1.Synthesis of allene-substituteds dihydropyrazoles by palladium catalyzed carboaminationDihydropyrazole skeleton is an important part of many active natural products and potential drug molecules.The synthesis of dihydropyrazole compounds through unsaturated hydrocarbon has attracted much attention of scientists.We have developed the first palladium-catalyzed carboamination of β,γ-unsaturated hydrazones with propargylic acetates to synthesize a series of allenyl substituted dihydropyrazole compounds.The advantages of this reaction system included mild reaction conditions,general substrate scope,and easy to scale-up.2.Palladium/XuPhos catalyzed asymmetric carboamination of alkenylhydrazoneBased on the previous research foundation,in this part we have successfully developed palladium/XuPhos catalysis asymmetric carboamination reaction of β,γ-unsaturated hydrazone with propargyl acetate.The reaction system has mild conditions,and the efficiently corresponding conversion can realized by the use of water as additive.It can synthesize a series of enantiomer enriched dihydropyrazole with excellent yield up to 96%ee.Chiral sulfosamide phosphine ligand Xu-5 has high efficiency and good enantioselectivity,and is widely used in asymmetric reactions.3.Palladium catalyzed asymmetric domino reaction for the synthesis of lactamsIn this chapter,we developed palladium/Phosphoramidites ligand catalysis asymmetric intermolecular tandem aza-Heck cyclizations reaction of unactivated alkenes(O-phenyl hydroxamic ethers)with ortho-alkynyl phenol,which delivering enantioenriched y-lactams that contain a tetrasubstituted carbon stereocenter with pendant functional benzofuran groups with good to excellent yields and excellent enantioselectivity(up to 99%ee). | Keywords/Search Tags: | palladium catalysis, unsaturated hydrocarbons, enantioselectivity, dihydropyrazole compounds, domino reaction | PDF Full Text Request | Related items |
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