Intermolecular Heck-Type Reaction Of Unactivated Alkenes And Alkyl Electrophiles Induced By Cleavage Of β-C-C Bond

Carbon-carbon double bonds exist widely in many chemicals such as drugs,natural products and spices.Therefore,how to efficiently prepare olefin compounds has always been one of the most popular research fields in organic chemistry.In the long-term development process,the coupling reaction in which the carbon-carbon double bond are directly involved has increasingly become an important"tool"for the synthesis of various substituted alkene,among which Heck coupling reaction is the most common.Traditional Heck reactions mainly use allyl halides or aryl halides as electrophiles for coupling reactions with alkenes.In contrast,Heck reactions involving alkyl electrophiles are rarely reported.This is mainly due to the very slow oxidation addition process of alkyl metal species,as well as their tendency toβ-H elimination.In recent years,with the rapid development of free radical chemistry,organic chemists use the single electron transfer（SET）mode of transition metal catalyst to produce alkyl radicals,and gradually realize a series of intermolecular free radical Heck reactions.However,the current research on activated olefin mainly focuses on activated olefin,with few reports on non-activated ones.This is mainly influenced by two factors:（1）the reactive activity of unactivated olefin is low,and it is difficult to effectively capture free radical species;（2）The selectivity ofβ-H elimination is difficult to control,resulting in poor regioselectivity.On the basis of previous work in our group,we used 8-aminoquinoline（AQ）as the directing group and realized the Heck type reaction between chained oxime ester and unactivated olefin under the catalysis of copper salt.In this work,we use stable and readily available oxime ester compound as the precursor of alkyl radical,make it undergo single electron transfer（SET）with copper salt to produce imine radical,and then release a molecule of acetonitrile throughβ-C-C bond cleavage to produce cyano-free alkyl radical.Heck type intermolecular coupling reaction between alkyl electrophiles and non-activated alkenes was realized without introducing special functional groups,which made up for the shortcomings of previous work to a certain extent.This reaction system showcases good substrate scope,with various aryl groups,heteraryl groups,all alkyl oxime esters and various substituted alkenes reacting smoothly.In addition,the reaction has excellent regio-and stereoselectivity,which provides an effective strategy for the preparation of multi-substituted alkenes.In this paper,based on the development history and current situation of Heck coupling reaction,combined with our research,the following three parts will be introduced.The first part:By referring to and combining with relevant literature,a brief summary was made on the studies on Heck coupling reactions of activated and non-activated olefin in recent years,and the future development of this field was prospected.The second part:the relevant research background,condition screening,substrate scope,mechanism research and other aspects are introduced in detail.In this reaction system,the Heck-type intermolecular coupling reaction between alkyl oxime ester and unactivated alkene was realized by catalysis of copper salt,thus preparing a series of multi-substituted olefin compounds.The third part:¹H NMR,¹³C NMR,IR,HRMS and other characterization methods were used to analyze the structure of the synthesized substrates and target compounds.