Study On Palladium Catalyzed Electrophilic Amination Domino Reactions

Organic compounds containing C-N bond widely existing in many bioactive natural products,synthetic intermediates,pharmaceutical agents,pesticide field and functional materials,are important raw materials of many chemical products.Therefore,the highly efficient,economic and environmental construction of C-N bond is always a hot research topic in organic chemistry.Compared with traditional methods,palladium catalyzed electrophilic amination of C-H bonds have emerged as one of the most efficient and straightforward for the construction of C-N bonds in organic synthesis,which have received considerable attention and intensive study in recent years.This dissertation mainly focuses on palladium catalyzed electrophilic amination of C-H bonds,aiming to explore more concise and efficient strageties to construct C-N bonds,and to establish a new method for new spirocyclic skeleton and 3,4-fused indole alkaloids.The discussions and results are listed as following: Chapter one mainly introduces the importance of nitrogen-containing molecules and the development to construct C-N bonds,especially focusing on transition metal catalyzed electrophilic amination pathway.Chapter two mainly introduces the recent progress of electrophilic amination initiated by various transition metal catalyzed reaction system involved O-benzoylhydroxylamines,including copper catalysis,palladium catalysis,rhodium catalysis,cobalt catalysis,iridium catalysis,nickel catalysis,ruthenium catalysis,iron catalysis and titanium catalysis.Based on the previous work,our design of research projects was proposed during the doctoral period.In chapter three,we present a novel catalytic spiroannulation reaction system of phenol compounds by using palladium catalyzed C-H bond amination/dearomatization approach,which allows the rapid synthesis of a new class of highly functionalized spiroindenes from readily available phenol-derived biaryls,NBD and N-benzoyloxyamines.This transformation results in a good yield with excellent functional group tolerance.Moreover,preliminary studies indicated that asymmetric control of this transformation was feasible with chiral ligands and the potential synthetic utility of this methodology was highlighted by a series of further transformation.In chapter four,we develop a new and general method for the construction of 3,4-fused tricyclic indoles with the stragety of palladium catalyzed C-H bonds amnination.In this work,we choose alkyne-tethered aryl iodides and N-substituted hydroxylamines as couping partners,through a sequence of alkyne migratory insertion to generate the allylpalladium in situ,activation of C-H bonds to generate five-member cyclometal intermediate and insertion of amination reagent.This transformation efficiency is excellent with broad substrate scope and tolerance against various functional groups,especially for thiophene and pyridine with strong coordination ability.Moreover,in order to further extend the substrate scope,we have designed and synthesized 3,5-3,6-fused indole derivatives with a 12-20 membered ring system by introducing heteroatoms O and N into the substrate,which enriched the application of this novel method and provided new ideas for the synthesis of the indole alkaloids.