(理学)加州大学伯克利分校有机化学课件

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1、Chapter20:CarboxylicAcidDerivativesOHbadleavinggroup1©UniversityofCaliforniaWhatistherelativereactivityofthesecarboxylicacidderivatives?MostreactiveLeastreactiveLtotheright,whenactingasNu,displacesthattotheleft>>>=L2©UniversityofCalifornia3©UniversityofCaliforniaOriginsofReactivityT

2、rendsInductiveeffectsElementstotherightinarowofPTaremoreelectronegative(nuclearchargeincrease).ElementsdownacolumninPTarelesselectronegative(size),butbondstothemgetweaker.4©UniversityofCaliforniaDonatingabilityofLdecreasesfromlefttorightintheperiodictable.Thegreatertheresonance,thes

3、hortertheC-Lbond.2.ResonanceeffectsAttheextreme:HinderedrotationinamidesontheNMRtimescale.Thenitrogenissp2-hybridizedtomaximizeresonance.AcetylchlorideAcetamide5©UniversityofCaliforniaDifferencesreflectedinpKavaluesBasicityProtonationgetseasierfromL=XtoOtoNForthesamereason,deprotona

4、tiongetsmoredifficult6©UniversityofCaliforniaComparingReactivityA.AlkanoylHalidesB.AnhydridesC.EstersD.AmidesE.Alkanenitriles7©UniversityofCaliforniaA.AlkanoylHalidesNames:Alkanoicacid→alkanoylhalideCycloalkanecarboxylicacid→cycloalkanecarbonylhalideCyclohexanecarbonylfluorideInanut

5、shell.......8©UniversityofCaliforniaMechanism:Example:1.Water:HydrolysisgivesRCOOH9©UniversityofCaliforniaGeneralReactionExample:60%2.Alcohol:R’OHconvertsalkanoylchloridesintoesters10©UniversityofCaliforniaWorksforNH3,RNH2,andRNHR’Reaction:3.AminesturnalkanoylchloridesintoamidesMech

6、anism:11©UniversityofCaliforniaRMgXatlowtemperature,orR2CuLi4.OrganometallicreagentstransformalkanoylchloridesintoketonesExamples:1.THF,-78°C2.H+,H2O12©UniversityofCalifornia5.ReductionofalkanoylchloridesresultsinaldehydesUsemodified(lessreactiveformof)LiAlH4Doesnottouchthealdehydep

7、roduct13©UniversityofCaliforniaB.AnhydridesNames:AddanhydridetotheacidnameAceticanhydridePentanedioicanhydride=Leavinggroup++Reactions:Similartoalkanoylhalides,butanhydridesarelesscorrosive,cheaper14©UniversityofCaliforniaMechanism:Examples:15©UniversityofCaliforniaRegioselectiverea

8、ction?Cyclicanhydri