ChapterThecarbon-carbonChapterThecarbon-carbondoublebond(C=C)isthefunctionalgroupofalkenes.Generalformula:UnsaturatedAlkenescontainlessthanthemaximumofStructureofStructureofTheC=Cbondenergyis605kJ/mol(144.5kcal/mol)inethyleneversus368kJ/mol(88kcal/mol)fortheC-Cbondinethane.Sobondisweakerthe§6-CarbonPosition§6-CarbonPositionofthedoublebondGeometricisomerismacgeometrica≠band acgeometrica≠band a=bornogeometricbdGeometricisomershavedifferentphysicalH CCHHHcis-2-trans-2-GeometricisomershavedifferentphysicalH CCHHHcis-2-trans-2-Relativedensity(at-010-DipoleTheirchemicalpropertiesaresimilarbutnotidentical;theyreactwiththesamereagents,butatdifferentrates(especiallyinbiologicalsystems).HHOOHHOOSelectastheparentstructurethelongestcontinuouschainthatcontainstheC=Cbond.Indicatebyanumberthepositionofthedoublebondintheparentchain.Indicatebynumbersthepositionsofthealkylgroupsattachedtotheparentchain.EachnameisderivedbychangingtheendingofthecorrespondingalkanenametoWhenageometricisomeristobespecified,aprefixisadded:cis-ortrans-,or(Z)-or(E)-.1-(cis-ortrans-)CCHC2-3,3-Dimethyl-1-(cis-ortrans-)2-乙基-1-4-甲基-2-1-(cis-ortrans-)CCHC2-3,3-Dimethyl-1-(cis-ortrans-)2-乙基-1-4-甲基-2-丙基-1-3-甲基-4-HCC(Z)-3-乙基-2-(E)-2,4-二甲基-3-乙基-3-(Z)-1,2-二氯溴乙trans-1,2-二氯溴乙Physical§Physical§6-??????SimilarwiththephysicalpropertiesofInsolubleinwater,butquitesolubleinnon-polarsolvents.Lessdensethanwater.Boilingpoint(b.p.)Meltingpoint(m.p.)Dipolemoment:verysmall,butlargerthan~ofAmethylgroupisanelectron-donatingsubstituentonthedoubleHHHHHHHμ=Amethylgroupisanelectron-donatingsubstituentonthedoubleHHHHHHHμ=HHHb.p.b.p.μ=0.35μ=0.37m.p.-m.p.-ChemicalTheChemicalThefunctionalgroupdeterminesthecharacteristicreactionsoforganiccompound.ofalkenesareoftwo Reactionsthattakeplaceatthedoublebonditselfanddestroyit——additionandoxidation. Reactionsthattakeplaceatcertainpositionshavingspecialrelationshipstothedoublebond——Additionreaction:Areactioninwhichtwomoleculestoyieldasinglemoleculeof+CYCZCCfreeradicalssourceAdditionreaction:Areactioninwhichtwomoleculestoyieldasinglemoleculeof+CYCZCCfreeradicalssourceofelectonsfree-radicalSubstitutionCCCHCCCX(X=Cl,I.CatalyticPt,Pd,or?H=heatofCI.CatalyticPt,Pd,or?H=heatofCC+CHCH1.Heterogeneoushydrogenationandhomogeneousor2.HeatHeatofhydrogenationandstabilityofThetransThetransisomeristhemorestablethanthecisisomer.ThegreaterthenumberofalkylgroupsattachedtothedoublybondedcarbonatomsthemoretheD2,MajorDDD2,+ DDD( D2,MajorDDD2,+ DDD( II.ElectrophilicII.ElectrophilicAdditionofElectrophilicElectrophilicIKI+88-IKI+88-Theregioselectivityofaddition——Theregioselectivityofaddition——Markovnikov’sIntheadditionofanacidtothecarbon-carbondoublebondofanalkene,thehydrogenoftheacidattachesitselftothecarbonthatalreadyholdsthegreaternumberofhydrogens.Stabilityofcarbocations:3o>2o>1o>+3HHActualCHHHMarkovnikov’sElectrophilicadditiontoacarbon-carbondoublebondinvolvestheintermediateformationofthemorestablecarbocation.HHActualCHHHMarkovnikov’sElectrophilicadditiontoacarbon-carbondoublebondinvolvestheintermediateformationofthemorestablecarbocation.Therelativereactivitiesof(CHTherelativereactivitiesof(CH3)2C=CH2>CH3CH2CH=CH2>CH2=CH2>Additionisaccompaniedbyrearrangements.2.Addition2.AdditionofsulfuricTheadditionofsulfuricacidfollowsMarkovnikov’s98%98%CH3CH2OH+3.Addition3.Additionofwater——4.AdditionofBr2/4.AdditionofBr2/ Br2/BrBr2/+Br2/+++++ThisreactionThisreactionisuseful??PreparationofvicinalHCHHHHCCCCH333HCHCHHH HH+CCHStereoselectivereaction：ReactioninwhichasinglestartingmaterialhastheHCHHHHCCCCH333HCHCHHH HH+CCHStereoselectivereaction：Reactioninwhichasinglestartingmaterialhasthecapacitytoformtwoormorestereoisomericproductsbutformsoneofthemingreateramountsthananyofitsstereoisomers.TermssuchasadditiontothelesshinderedsidedescribeStereospecificreaction：Reactioninwhichstereoisomericmaterialsgivestereoisomericproducts.Termssuchassynaddition,antiAnti--III.Free-radicaladditionofnoIII.Free-radicaladditionofnonoMarkovnikovPeroxidePeroxide>Stabilityoffree3o>>Stabilityoffree3o>2o>1o>ThepresenceorabsenceofperoxideshasnoeffectonorientationofadditionofHCl,HI,H2SO4,H2O,IV.Hydroboration-H2O2,CHC+HBCHCBCC BHRH=H,HB+IV.Hydroboration-H2O2,CHC+HBCHCBCC BHRH=H,HB++(1)B2H6,(2)HO, No++δδH-- δ HH HHTransitionstateforAnti-(1)B2H6,HH+(2)H2O++δδH-- δ HH HHTransitionstateforAnti-(1)B2H6,HH+(2)H2O2,OxidationcoldalkalineCCCCCCOO OOK1,2-diolRRC+COOCCHHO KMnO4,CH3CH2COOHOxidationcoldalkalineCCCCCCOO OOK1,2-diolRRC+COOCCHHO KMnO4,CH3CH2COOHKMnO4,O+KMnO4,+Thisreactionisuseful??DeduceKMnO4,O+KMnO4,+Thisreactionisuseful??DeducethestructureofOOCCNaO23OOOCCCCOPhase-transferˉ4Phase-transferˉ4permanganate?2.Ozonolysishas2.Ozonolysishasbothsyntheticandanalyticalapplicationsinorganic3.3.OCH3 H H3H+CC3HOCH3OHHH3++CC HO3Ring-openingpreparationofanti-1,2-OCH3 H H3H+CC3HOCH3OHHH3++CC HO3Ring-openingpreparationofanti-1,2-VI.AllylicHCCC+XCCCX2=Cl2,Stabilityoffreeradicals:CHCH2>3o>2o>1o>>VI.AllylicHCCC+XCCCX2=Cl2,Stabilityoffreeradicals:CHCH2>3o>2o>1o>>lowCH3280-gasOO++ON-O82-VII.MonomerO2nn1×108－1.5×108TiCl4/n VII.MonomerO2nn1×108－1.5×108TiCl4/n n1×105－1×106 CHn22nChemicalpropertiesofChemicalpropertiesofCatalyticElectrophilicaddition(HX,H2SO4,H2O,X2,HOX)AdditionoffreeradicalsSynadditionthatfollowsanti-MarkovnikovAllylicsubstitution2005年Nobel化學獎——烯烴復分解反應 XXXnR+RXXnR1++n2005年Nobel化學獎——烯烴復分解反應 XXXnR+RXXnR1++n烯烴復分解催化劑的發展概R R R++RRR121Chauvin催化機理 NO1O FSchrock,3F3C Ph332烯烴復分解催化劑的發展概R R R++RRR121Chauvin催化機理 NO1O FSchrock,3F3C Ph332Grubbs,Grubbs,4Grubbs,PreparationofI.ReductionofRRHHCLindlarPreparationofI.ReductionofRRHHCLindlarRCCNaorliq.II.DehydrationofII.DehydrationofEaseofdehydrationof3o>2o>III.DehalogenationofvicinalCXCX+CCZn/+BrCIII.DehalogenationofvicinalCXCX+CCZn/+BrC2H5O-/IV.DehydrohalogenationofalkylCHCX++ >2o>ReactivityofRXtowardSaytzeff’srule:indehydrohalogenation,themorestablethealkene,thefasteritisformed.StereochemistryoftheE2-IV.DehydrohalogenationofalkylCHCX++ >2o>ReactivityofRXtowardSaytzeff’srule:indehydrohalogenation,themore