Transition-Metal-Catalyzed Radical Transformations Of Alkenes And Aziridines

Both alkenes and aziridines represent important structural units that found in pharmaceuticals,natural products and organic functional materilas,as well as important synthetic intermediates in organic synthesis.Therefore,the development of efficient methods for their transformations are desirable and attract much attention from the organic chemists.For example,transformations of aziridines through ring opening would afford ethylamines which are monoaminergic neuromodulators and serve as the versatile synthetic building blocks in synthsis and industries.To date,both the alkene difunctionalization reactions and the ring-opening cross-coupling of aziridines have been well investigated to incrase molecular complexity.However,efficientroutes for the precisely-controlled selective transformations of alkenes or aziridines still remain challenging and are the focus of the synthetic chemistry community.This thesis aims to develop the green,efficient,highly selective catalytic strategies to enable both the alkene difunctionalization reactions and the ring-opening cross-coupling of aziridines.This paper focuses on the development of new radical strategies to allow transition-metal-catalyzed alkene radical difunctionalization reactions and ruthenium/nickel co-catalyzed aziridine radical ring opening alkylation reactions for selective construction of complex compounds.It mainly includes the following five parts:(1)Recent advances in the the alkene difunctionalization reactions and the ring-opening cross-coupling of aziridines using the photoredox catalysis or the oxidative radical strategies are summarized.Moreover,the mechanisms for these reactions are also discussed in detail.(2)A unparalleled visible-light-promoted strategy has been proposed for the1,2-dialkylation of alkenes with α-carbonyl alkyl bromides and heteroarenium salts involving dearomatization at room temperature.Especially,pyridinium salts are utilized as radical receptors via dearomatization.This mild three-component reaction allows the simultaneous incorporation of ?-carbonyl alkyl and 1,4-dihydropyridine groups across the C=C bonds to access various ester group containing1,4-dihydropyridine derivatives with a wide range of substrates.Control experiments show that the reaction proceeds via radical-mediated three-component difunctionalization of alkenes irriated by visible light.(3)A new copper-catalyzed highly regioselective 1,2-difunctionalization of unsaturated alkenes with phosphite oxides and indoles is described,in which 1,2-alkylphosphinoylation is efficiently and oversimply constructed under oxidation conditions with excellent functional compatibility and a widely range of substrate adaptability.The control experiments suggest the reaction involving a radical process,in which copper and oxidants co-initiated the generation of phosphonic acid radicals.(4)A cross-electrophile coupling of aziridines with pyridin-1-ium salts through dearomatization enabled by the cooperative photoredox/nickel catalysis for producingβ-(1,4-dihydropyridin-4-yl)-ethylamines,especially including bioactive motif-based analogues is developed.The reaction enables introduction of a1,4-dihydropyridin-4-yl group and formation of a N-H amino group in a single reaction step to access highly valuable β-(1,4-dihydropyridin-4-yl)-ethylamines via a sequence of cleavage of the C2-N bond regioselective and dearomatization alkylation featuring precise regioselectivity and an excellent tolerance of functional groups.This reaction provides an efficient cross-electrophile coupling route to achieving transformations between two electrophiles,including aziridines and pyridin-1-ium salts,by avoiding prefunctionalization.Control experiments support a radical process for the cross-electrophile coupling of aziridines with pyridin-1-ium salts.