Study On Amination And Borylation Of C–C Double Bond

Unsaturated hydrocarbons are important and large quantity raw chemical industrial materials,and installation of various requisite functional groups into unsaturated hydrocarbons through the appropriate chemical conversions,has a significant theoretical and practical values.Difunctionalization of C–C double bond has attracted increasing attention of chemical scientists in recent years,owing to its having the high step-and atom economy and the high efficiency in the synthesis of complex molecules.Currently,asymmetric synthesis plays a very important role in drug synthesis and total synthesis of natural products.Undoubtedly,the enantioselective difunctionalization of C–C double bond to create two different stereochmical centers simultaneously through employing olefins as the feedstocks,represents an efficient asymmetric synthetic methodology.Nitrogen-and fluorine-containing organic compounds are widely found in medicine,agriculture and food industry and are closely related in people's life.Therefore,the development of a novel and efficient method for C–N and C–F bond formation has significant values.On the other hand,organoboron and organosilicon derivatives are important compounds and have widely applications in material and pharmaceuticals,etc.Meanwhile,organoboron compounds have the following characteristics,including the high stability,modest reactivity and versatile reaction types,and have become the important organic synthetic intermediates.Hence,the development of an efficient methodology for C–B bond formation,especially for construction of C–B bond in enantioselective manner,as well as its transformations,have significant theoretical and practical values.Due to the importance of nitrogen-containing organic compounds,organoboron and organosilicon derivatives,and the important role of organoboron in synthetic chemistry,as well as the importance of asymmetric synthesis,this thesis realizes a series of new methods for C–N and C–B bond formations through the use of cheap,readily available and environmental friendly copper salts and silver salts as the catalysts and employing olefins as the feedstocks,and mainly contains the following three aspects.1.Allene is having unique structure,versatile reaction types and has the characteristics of high reactivity and multiple reactive sites.On account of the poor regioselectivity of allene via radical pathway,we employed copper salt as the catalyst and N-fluoroarylsulfonimides(NFSI)as the source of nitrogen radical.As a result,the challenging ?-H elimination of vinyl-metal intermediate has been successfully realized and the high regioselective C–H bond radical amination,providing the important multi-substituted allenamides,has been achieved for the first time.Furthermore,the Ag-catalyzed regioselective intermolecular radicalaminofluorination of allenes to furnish the valuable tetrasubstituted fluorinated alkenes has also been described via fluorine-atom-transfer pathway.2.We developed a novel CuCl/(S,S)-Ph-BPE catalyzed highly regio-,diastereo-,and enantioselective borylcarbonation reactions for the synthesis of 2,3-disubstituted indolines in high yield and enantioselectivity(71%-96% yield,d.r.>25:1,77%-99% ee)under mild reaction conditions.This transformation creates C–C and C–B bonds and two stereogenic carbon centers simultaneously in one operation.Furthermore,the borylated indolines can serve as the versatile intermediates to synthesize multifunctional chiral indole compounds,these processes in which retention of stereochemistry when C–B bond was tansformed to corresponding C–N,C–O,C–C bond.3.Compared with the construction of chiral carbon central,the synthesis of the stereogenic silicon-containing is more challenge.Desymmetrization reaction of prochiral silanes is the most direct and effective strategy for the creation of chiral organosilicon compounds.However,the silicon compounds tend to racemization via Berry pseudorotation form Si(V)intermediates.We developed a catalytic asymmetric method for the construction of chiral silicon center through copper–catalyzed hydroboration of vinylsilanes.A various of chiral organosilicon compounds containing consecutive silicon-and carbon-stereogenic centers can be synthesized with high regio-? diastereo-and enantioselective(49%-95% yield,d.r.1.7:1~>25:1,79%-98% ee).Furthermore,this protocol provides a new avenue to the synthesis of the highly functional groups,multi-stereocenter organosilicon-containing compounds.