Alkene And Alkyne Oxidative Radical Difunctionalization Reactions

Unsaturated hydrocarbons,including olefins and alkynes,that serve as important chemical raw materials and organic synthesis materials play a very important role in organic synthesis,pharmaceuticals,materials chemistry,dyes and energy material chemistry due to their cheap,readily available and highly reactive chemical properties.In the past few decades,transformations of both alkenes and alkynes have attracted the increased interest of many chemists,in which many major breakthroughs have been achieved,such as the Heck reaction with alkenes and the Sonogashira coupling reaction with alkynes.In recent years,functionzalization of unsaturated hydrocarbons using the free radicals strategy has aroused widespread interest and attention of chemical researchers because such radical strategy has the advantages of simple operation,environment-friendly,high step economy and atomic economy.Therefore,functionalization of olefins and alkynes through the radical strategy would be challenging with importantly academic and practical valuesThis dissertation has developed some oxidative radical difunctionalization reactions of olefins and alkynes,which mainly focuses on the following five parts:(1)The recent progress in the functionalization of olefins and alkynes initiated by carbon-centered radicals was reviewed.Radical functionalization reactions of olefins and alkynes are introduced mainly from three aspects,such as radical-initiated olefin and alkyne coupling reactions,intramolecular 1,2-difunctionalization and intermolecular 1,2-difunctionalization.(2)A new silver-mediated radical 1,2-alkylarylation of styrenes with?-carbonyl alkyl bromides and indoles that facilitated by iron catlyst is described,in which two new C-C bonds were generated in a single step through a sequence of intermolecular C(sp~3)-Br functionalization and C(sp~2)-H functionalization across the alkenes.This method provides an efficient access to alkylated indoles with broad substrate scope and excellent selectivity.(3)A general and metal-free radical route to synthesis of3-acylspiro[4,5]trienones is established that utilizes TBHP(tert-butyl hydrogenperoxide)as an oxidation and a reaction partner to trigger the oxidative ipso-carboacylation of N-arylpropiolamides with aldehydes.This method offers a new difunctionalization of alkynes through oxidative cross coupling of the aldehyde C(sp~2)-H bond with an ipso-aromatic carbon.(4)A Cu-catalyzed oxidative ipso-annulation of activated alkynes with unactivated alkanes for the synthesis of 3-alkyl spiro[4,5]trienones has been developed.This method allows the formation of two carbon–carbon bonds and one carbon-oxygen bond in a single reaction through a sequence of C-H oxidative coupling,ipso-carbocyclization and dearomatization.(5)A new metal-free tert-butyl hydroperoxide(TBHP)-mediated carbonyl C(sp~2)-H oxidative alkynylation of aldehydes with ethynyl benz-iodoxolones(EBX)for the synthesis of ynones is presented.This method is based on a carbonyl C(sp~2)-H oxidative radical coupling process according to mechanistic studies,and provides a general route to the assembly of diverse ynones with a broad substrate scope and excellent functional-group compatibility.