Radical Reactions Involving Alkenes

The widespread use of free radicals play an important role in the manufacture of plastics and rubbers,as well as in medicine,agriculture,biochemistry and a variety of chemical processes.As early as in 1900,Gomberg have found trityl free radicals and opened the rational era of free radical chemistry,but for a long period of time,these species,born with high reactivity,were considered to be chaotic,uncontrollable,and mysteriously baffling.After the development for more than a century,free radical chemistry has cast off the discrimination and usher in its renaissance.Owning to the unique reactivity and selectively,radicals have been used time and again to solve difficult synthetic problems,which used to be challenge in traditional methods.Olefins are critical important chemical raw materials.It's not only the starting materials of many chemicals but also the extremely useful C2 linker in organic synthesis chemistry.Through the reactions on unsaturated C=C bond,various functional groups can be effectively connected to achieve higher molecular complexity.The thesis illustrates the characteristics of free radical chemistry,starting from its long and storied history.Further,several important radical transformations involving olefins are introduced.Then two models of radical reaction involving olefins are proposed:acting as free radical acceptor or free radical precursor.Research were carried out according to the role of alkene.New methods are developed for the functionalization of alkene,using alkene as radical acceptor.In addition,an alternative approach have been proposed for the olefin in radical reactions,and the corresponding mechanism studies and methodologies have been developed.The main results of the paper are as follows:1.The radical alkenylation of bromobenzene or a-carbonyl bromide was achieved using a copper catalyst system.The mechanism studies show that the single electron transfer between Cu? species and bromide produces alkyl radicals.Olefins acted as radical acceptor in radical addition process.This study focuses on the alkenylation of bromobenzene(1° alkyl bromide).It was also compatible with secondary or tertiary alkyl bromides commonly used in other free radical alkenylation reactions which expanding the application of radical alkenylation.2.A three component alkoxycyanomethylation of alkenes is achieved using photoredox catalyst Ir(ppy)3.This catalytic radical difunctionalization accomplishes both alkylation and alkoxylation of alkenes in one pot.Various alcohols can serve as the alkoxy resources in this transformation.In addition,the introduced cyano group can undergo many transformations into various useful functional groups.3.Using XAFS/EXAFS and EPR techniques,a single electron transfer path between alkene and Cu(OTf)2 is investgated.Cu? was reduced to Cu? species while alkenen was oxidized into radical cation.The particularity of the solvent and the olefin qualified for this redox process has been clarified in case studies,which presents a potential radical initial method for alkene functionalizatin.4.A transformation is presented that enables chemists to construct 4-aryl tetralones via visible-light-induced cyclodimerization-oxygenation of styrene under very wild conditions.Adding catalytic amount of CuOAc obviously improves the yield.Mechanism study reveals that photoredox catalyst played the role of activating O2 while Cu affected the reactivity of reactive oxygen species(ROS).