金属有机化学上科大

III.MigratoryInsertion&de-insertion

CO插入到M－R键中，生成酰基金属化合物[途径(I)]；

与金属以s键相连的R基团移位到CO上[途径(II)]。采取何种途径迁移？同位素标记实验：甲基迁移MigrationofthealkylgrouptotheCOligandismorecommon.ChangesinGeometryandElectronCountDuringMigratoryInsertion:Usuallynochangeinformaloxidationstate;Theparticipatinggroupsmustbecistoeachother;Theforwardinsertioncreatesavacantcoordinationsite;andavacantcoordinationisneededforthereversereactiontooccur;Migratoryinsertionoccursbyaconcertedprocesswitharetentionofconfigurationattheα-carbonofamigratingalkylgroup;Twotypes:COinsertionintoM-alkylbondsMigratoryinsertionoccurswiththeretentionofconfigurationattheα-carbon.COinsertionintoM-alkylbondsMigratoryInsertionMechanism;Thecarbonylgroupandthealkylgroupmustbecistoeachother;IfCOinsertionisreversible,therateisdependentontheingligand;ifirreversible,therateisindependentontheingligand.COrarelyinsertsintoM-HbondsCOinsertionintoM-alkylbondsThermodynamiceffectsandkineticeffectsThemoreelectron-donatingalkylgroupsismorefavorablethanthelesselectron-donatinggroupsformigratoryinsertion.

See362,theHartwigtextbookCOinsertionintoM-alkylbondsThermodynamiceffectsandkineticeffectsCOinsertionintoM-alkylbondsCOinsertionintoM-XbondsDe-insertionofCOCO2insertionintoM-Hbonds甲酸盐型金属羧酸盐型FindapplicationinreductionofCO2OlefininsertionintoM-Hbondsandβ-HeliminationsAcrucialstepinolefinhydrogenationandhydroformylationCoplanarAfour-memberTSSynadditionalkyneinsertionintoM-HbondsAlkynehydrogenation,hydrosilylation,dimerizationetc.CoplanarandcisadditionalkyneinsertionintoM-HbondsTheformationofatransadditionproductviatheformationofavinylintermediate.Olefininsertionintometal-hydrocarbylbondsM-HbondsarestrongerthanM-Cbonds,butstericeffectplaysaroleAcrucialstepinolefinpolymerizationoroligomerizationRegioselectivityinolefininsertion1,2-inerstionvs2,1-insertionOlefinscontainingelectron-withdrawinggroups,suchascarboalkoxygroupsorarylgroupsfavor“2,1-insertion”EWGonanα-carbontendtostrengthM-Cbondsbycreatingamorepolarbondandbystabilizingthepartialnegativechargeonthealkylgroup.Aryl-substitutedolefinsfavor“2,1-insertion”byadoptionofanη3-benzylstructureOlefinInsertionintoMetal-acylbondsAlternativeco-polymerizationofCOwithethyleneInsertionofethyleneintometal-acylbondisfasterthantheinsertionintometal-alkylbonds.IV.ReactionsonCoordinatedLigands4.络合配体的反应配位的烯烃的反应配位的炔烃的反应

配位的芳烃的反应配位的CO的反应4.络合配体的反应与金属配位的烯烃受到活化

烯烃更加缺电子，容易接受亲核试剂进攻

亲核试剂从金属的反面进攻，同时形成C-M键。配位的烯烃的反应4.络合配体的反应反式加成：立体化学证据配位的烯烃的反应4.络合配体的反应

WackerProcess配位的烯烃的反应4.络合配体的反应反式加成：立体化学证据配位炔烃的反应4.络合配体的反应明显提高芳环的亲电性能配位芳环的反应4.络合配体的反应配位的CO发生极化，容易接受亲电和亲核试剂进攻配位CO的反应4.络合配体的反应配位的CO发生极化，容易接受亲电和亲核试剂进攻配位CO的反应二、有机过渡金属络合物的基元反应4.络合配体的反应配位CO的反应Männig,D.;Nöth,H.,Angew.Chem.Int.Ed.Engl.1985,

24,878.alkenehydroborationSynthesisof(PNN)FePincerComplexEasytoprepareElectron-richironcenterGoodthermostabilityAirandmoisturestableIron-catalyzedalkenehydroborationElectron-richFecomplexoftridentatePNNligandismoreefficientthanthecomplexesofbidentateNNandNNNligands;ItisevenmoreefficientthanthetraditionalRhandIrcatalysts.Iron-catalyzedalkenehydroboration(PNN)Fe-CatalyzedHydroborationofVinylarenesSolventeffect!MeCNinhibitsboththealkenehydroborationanddehydrogenativeborylationprocesses,butthe“suppressingeffect”ofacetonitrileonthelatterismor