有机化学教材McMurry39;sOrganicChemistry的课后习题答案Chapter23

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1、Chapter23-CarbonylCondensaChapterOutlineI.Thealdolreaction(Sections23,1一23.6).A. Characteristicsofthealdolreaction(Sections21. Thealdolcondensationisabase-catalyzedcketones2Thereactioncanoccurbetweentwocompo3. Forsimplealdehydes,theequilibriumfavoiandketones,theequilibriumfavorsthereac4Onecomponent(

2、thenucleophilicdonor)isana-substitutionreaction.5Theothercomponent(theelectrophilicacce6Carbonylcondensationreactionsrequireon232)Alpha-substitutionreactions,ontheothB. Dehydrationofaldolproducts(Section23.3).1Aldolproductsareeasilydehydratedtoyielketonesa.DehydrationiscatalyzedbybothacidaibReaction

3、conditionsfordehydrationarecondensationc.Often,dehydrationproductsareisolatec2.Conjugatedenonesaremorestablethannoi3Removalofthewaterbyproductdrivestheformation.C. Aldolproducts(Sections23.4一23.5).1. Usingaldolreactionsinsynthesis(Sectiona.Obviousaldolproductsare:608Chapter233Amajordifferencefromthe

4、aldolcondensationistlfromthetetrahedralintermediateoftheinitialClaist4. Becausetheproductisoftenacidic,oneequivalentbasedrivesthereactiontocompletion.5. Additionofacidyieldsthefinalproduct.BMixedClaisencondensations(Section23.8)1MixedClaisencondensationsoftwodifferentester:hasnoahydrogens2. MixedCla

5、isencondensationsbetweenaketoneancarealsosuccessful.CIntramolecularClaisencondensations:theDieckmann(1TheDieckmanncyclizationisusedtoformcyclic卩a.1,6-Diestersform5-memberedringsb1,7-Diestersform6-memberedrings2. ThemechanismissimilartotheClaisencondensate-3Theproductp-ketoesterscanbefurtheralkylated

6、Thisisagoodrouteto2-substitutedcyclopentaIII.Othercarbonylcondensationreactions(Sections23.1023,1A. TheMichaelreaction(Section23.10).1TheMichaelreactionistheconjugateadditionofancarbonylcompoundThehighest-yieldingreactionsoccurbetweensta,p-unsaturatedcarbonylcompounds2.Themechanismisaconjugateadditi

7、onofanucleopa,卩carbonylacceptor3StableenolatesareMichaeldonors,anda,p-unsaturacceptorsB. TheStorkreaction(Section23.11)1. AketonethathasbeenconvertedtoanenaminecanreactionknownastheStorkreaction2. ThesequenceofreactionsintheStorkreaction:a.Enamineformationfromaketone.hMirhnpl-tvneadditinntnnnrrR-unR

8、AtnrAtednarlSolutionstoPro23.1(1)FormtheenolateofonemoleculeofthecarbffCHqCHoCHCH+：OH32yH.丿ft:CHCHCH2CH(2)HavetheenolateattacktheelectrophiliccarbCH3CH2CH2CH+；:CHCHW上CH3丿CH2CH3(3)Protonatethealkoxideoxygen.：O：oUIIICH3CH2CH2CCHCH5=HCH2CH3ch3ch;PracticewritingoutthesestepsfortheotheraidSolution:/：0Hur

9、/nCH2CCH3CH3ffch3cch2cch3ch3(2)Eliminatetheenolateanion.ch3cch2cch3*JCH3oII_CH3CCH3+-：CH(3)Reprotonatetheenolateanion.610Chapter2323.2ch3cch2cch3ch34-Hydroxy-4-methyl-2-pentanoneThestepsforthereversealdolarethereverseofthosedes(1)Deprotonatethealcoholoxygen.23.3Strategy:AsinProblem23丄alignthetwocath

10、enewbondisapparent.AfterdrawingtheadcproductbydehydrationInparts(b)and(c),aiSolution:NaOH,EtOH(c)OHCh3coneH3C(CH3)2CHCH2CH+oIIch2chNaOH,(CHEtOH612Chapter2323.4Includingdoublebondisomers,4productscanbeformecbyreactionoftheenolateformedbyabstractionofaprotcaNaOH,AEtOH+Omajor(lesshindered)(a)CHO#Chapte

11、r23(a)CHO#Chapter2323.5(a)CHO23.6OII2CH3CH1NaOH,EtOH】2.heatOIICH3CH=CHCH23.8OHNHHaooEtoCyclopropylacetaldehyde(a)ohchNaOH,+8CH3CCH3EtOH614Chapter231NaOH,EtOH2.heatCH3CH2CHO23.9NaOHone一：CHAOHC3oAchch2ch3+Asin(b),amixtureofproductsisformedbecausebothcshydrogenatoms.Theuppertwoproductsresultfrommixctwo

12、areself-condensationproducts.#Chapter23HqCczc=cCH3CCH2CCH3NarOOII11-H3H3CCH2CCH2B2,4-Pentanedioneisinequilibriumwithtwoenolateions;Aisstableandunreactive,whileenolateBcanundergoinacyclobutenoneproduct-But,becausethealdolreactionicyclobutenoneproductishighlystrained,thereislittleofennilihrinmisreache

13、d.Ateauilihrium-onlvthestable,dil23.11 Asinthealdolcondensation,writingthetwoClorientationmakesiteasiertopredicttheproduclOIICH2COEtCH(CH3)21. Na42. H3C(CH3)2CHCH2COEt23.12OEt616Chapter2323.12 AsshowninWorkedExample23.4,dimethyloxalateis2Claisenreactions.#Chapter2323.14Diethyl4-methylheptanedioateCH

14、，#Chapter2323.15#Chapter23#Chapter23IlNa+OEtC1-C6bondformati23.13 AMichaelreactiontakesplacewhenastableen(doublebondofana?p-unsaturatedcarbonylcoiraddstothedoublebondoftheconjugatedsysteiwhenthedonorandacceptorarepositionedsotMichaelDonor(a)zPch3c/CH2ch3coMichaelAcceptor(b)h2c=chc=nch3c/CH2ch3coh3c(

15、c)/pch3c严2ch3c/PC=CHCOEt23.17618Chapter2323.14 FindthecarbonylgroupoftheMichaelacceptor,andcoucarbonylgroup.TheMichaeldonorformsthenewbondiidentifytheMichaeldonorandMichaelacceptor.H3C6+、onN七XHHwcy.tHHOnc1H2.曰_o#Chapter23#Chapter23Enamine(a)Michaelwnewbondformed23.19Anenamineisformedfromaketonewheni

16、tisnecessary1,5-dicarbonylcompoundcontaininganaldehydeorketoiconvertedtoanenamineinordertoincreasethereactivityregiochemistryofadditionTheprocess,asdescribedin；ofaketonetoitsenamine;(2)Michaeladditiontoana,P-i(3)hydrolysisoftheenaminetothestartingketoneMichaelAcceptorOIIH2C=CHCOEt#Chapter23#Chapter2

17、3one23.20AnalyzetheproductfortheMichaelacceptorancpropenenitrileTheketoneiscyclopentanone,wtenamine.bzlk+h2o23.21TheRobinsonannulationisacombinationoftwMichaelreactiontakesplacebetweenanucleopbandana,p-unsaturatedcarbonylcompound(theinanalrlclraacNcnThaKqqar卜620Chapter2323.22OIIch3ch2cch=chMichaelac

18、ceptorMichael凶3Na+PEEtOHdonorThisisoneofthemorecomplicated-lookingsynthesesttheproductforthetwoMichaelcomponents.Thecarboidehydrationofthealdoladditionproduct,andislocatedoftheoriginaldiketoneusedtobe.TheMichaeladditiontheseketonegroups.TheMichaelacceptorisanenonetlcondensationandfurnishesthemethylg

19、roupattachedtcVisualizingChemistry23.23(a)23.24TheenolateofmethylphenylacetateaddstoaformtheClaisenintermediatethatispictured,acidificationgivetheproductshown23.25Methyleno/OCH3Na+PEt,EtOHpnenylacetateoneHHO4-Oxoheptanal622Chapter23AdditionalProblems23.27(a)(CH3)3CCHOhasnoahydrogensanddoesnotunde(b)

20、NaOH,EtOHBenzophenonedoesntunaldolselfcondensationbehasnoahydrogens(d)NaOH,厶0EtOH2CH3CH2CCH2CH3ch2ch3H3CO3|IICH3CH2C=CCCFch2ch3(e)rsii23.28Asalways,analyzetheproductforthecarbon-cidehydrationoftheinitialaldoladduct.Breaktheappropriatecarbontoidentifythecarbonylreactsa)o3Cone1. NaCEtO2. heal(b)1NaOH,

21、EtOH2.heat(C)/X/CH2CH0CHoCHO1NaOH,EtOH2.heat%C6OHC0C5H5bb1NaOH,EtOH2.heat624Chapter2323.31 ProductA,whichhastwosingletmethylgroupsandnothemajorproductoftheintramolecularcyclizationof2,：23.32areactantwithapr(H2-OUH23.32 Thereactivenucleophileintheacid-catalyzedaidreactants.TheelectrophileisStep1:Enol

22、formation.Step2:AdditionoftheenolnucleophiletothepelectrophilenucleophileStep3:Lossofprotonfromthecarbonyloxyg23.34H:OH2HOR/cRHnCNaOH,626Chapter2323.35CHO+CH3CHO1NaOH,EtOH)2.heat0#Chapter230#Chapter23Althoughself-condensationofacetaldehydecantakepla(predominates23.36Thefirststepofanaldolcondensation

23、isenolateformatinotenolizebecausedoublebondsatthebridgeheadofsnstrainedtoform.Sincethebicyclicketonedoesnotenol:condensation23.37o0II1.NaOEt,IIEtOHCH3CH2CH2COEt+CHoCOEtr*CHqC卜1ch2ch32.H3O+(b)0#Chapter231NaOH,EtOHA2.heat0#Chapter230#Chapter23(001NaOH,EtOHO*023.39A1NaOEt,EtOH”2.H3O+CH3CH2CCHCself-cond

24、ensationprocoIICH3COEt+OIICH3CH2COEtooIIIICH3CCH2COEAAApproximatelyequalamountsofeachproductwreactivity(b)OIIC6H5COEt+OIIC6H5CH2COEt1NaOEt,EtOHrC6H5CH2CCHCself-condensationprAAThemixedcondensationproductpredominates.AA1NaOEt,EtOH”2旳0广OA628Chapter2323.40#Chapter23#Chapter23：O：llCH3CC(CH3)2COEtadditio

25、nofethoxideJ：0Et0IIC(CH3)2COEtOOII人IICH3CCHCOEt+oIICH3CC(CH3)2COEtOEtnEtOH(CH3)2CHCOEt+一OEtThisisareverseClaisenreaction.23.41 TwodifferentreactionsarepossiblewhenethylacetoaceOnepossibilityinvolvesattackofethoxideiononthecaieliminationoftheanionofethylacetateareverseClaisiillustratedin23.40.Morelik

26、ely,however,istheacid-bgdoublyactivateda-hydrogenofethylacetoacetateTheresonance-stabilizedacetoacetateanionisnolongernofurtherreactionoccursatroomtemperature.ElevatedthecleavagereactionproceedThiscomplicationdoesntdimethylacetoacetatebecauseithasnoacidichydrogens23.42 Michaelreactionsoccurbetweenst

27、abilizedenolateanioncompounds.Learntolocatethesecomponentsinpossibleasiertorecognizetheenolatenucleophile;in(a),thenucanion.TherestofthecompoundistheMichaelacceptor.(b)WhentheMichaelproducthasbeendecarboxymoredifficulttorecognizetheoriginalenolateaniiIICH3CCH2+CO2EtOIIH2C=CHCCH31NaOEt,一旦C2.H3O+Micha

28、eldonorMichaelacceptorniiCH3CCHch2ch2cch30H3O+H_CHoCCHoCheatdwCO2Et(c)IIEtOCCH2+CO2Eth2c=chc=n1NaOEt,EtOH厂3MichaeldonorMichaelacceptor(d)CH3CH2NO2+H2C=CHCOEtMichaeldonorMichaelacceptor1NaOEt,EtOHy冇30厂(e)1.NaOEt,630Chapter2323.431,Na+一OEt,2卯乂比3.H3O+#Chapter23#Chapter23Thissequenceofreactionsconsistso

29、fanalkylationofaRobinsonannulationThecarbon-carbondoublebondigroupofthediketoneusedtobeandisthesiteoftherirMichaelreactionbetweenthediketoneandtheMichaelicarbonatomsusedtoformthesecondring,andanalky!group23.43 (a)Severalotherproductsareformedinadditiontotheacetaldehydeandacetone(lesslikely)canoccur,

30、andanformed.(b)Therearetwoproblemswiththisreaction(1)Michimonoketones-Formationoftheenamine,followedby1yieldofproduct.(2)Additioncanoccuroneithersideoproducts.23.45O1.a1.Cf2.b7丿2d1(a)LiAlHt,thenH3O+;(b)POCI3,pyridine(c):(e)Na+-OEt;(f)H3O+;(g)Na+OEt,thenCH?23.46(a)O+2C6H5CHO1. NaOH,C6kEtOHA2. heat(b)

31、2.卜1.卜632Chapter2323.47Thissequenceisareversealdolreaction.#Chapter23#Chapter230II/C、H3CSCoA3.v0II3、/C、c、CH3/dHHAcetylCoAAcetoacetateStep1:Deprotonationbybase.Step2:EliminationofacetylCoAenolate.Step3:Protonationofenolate23.48Incontrasttothepreviousproblem,thissequenceisare、step(notillustrated)isthe

32、reactionofHSCoAwithabas#Chapter23#Chapter23、SCoAOHC3CH1.CoASC：23.49Formationof(5)-citrylCoA:Step1:FormationofacetylCoAenolateStep2:Aldol-likenucleophilicadditionofacetyloxaloacetateandprotonationLossofCoAtoformcitrate:qc、O2cxStep1:NucleophilicadditionofhydroxyltotheSten2:Lossof一SCoAandorotonationoft

33、hele634Chapter23#Chapter23(b)OoESC、丿、c23.51w、CO2EtMichaeladditionch3：0：H2C、“C、CO2EtTheprotonatedformoftheabovestructureistheprodu(c)EtO2CH2CQEtcl、一-HoneH2c.cinternalHqC、aldol/CHconden-EtO2CHsationd)oneCHlH2CEt02H3cH、HOtheat丁Jcestercleavageanddecarboxylation2Cofap-ketoacidEtO2Hagen23.5323.5323.5423.5

34、3Oiinch3ch2cch=ch223.5323.53o636Chapter23MichzadditiofeneCOTNoticethattheneededenamineisformed(seeProblem:(c)A23.55CH2(CO2Et)2+_OEt:CH(CO2Et)23.55hydiH：O：IIC、_八2additionofOacetylCoAHO、CO?一H2Co、SCA-：CH2CSCoAoxidation(decarboxylationofap-ketoacidH,eno3HN202cnucleophilicacylsubstitution,lossofH?O,reduc

35、tion23.56FormationoftheenolateofdiethylmalonateistCH2(CO2Et)2+_OEt:CH(CO2Et)638Chapter2323.57CICH2CO2EtCICHCO2Et+Sn2displnucleophilicaddition#Chapter23#Chapter23ch2co2h23.58 Thismechanismdividesintotwosequencesofsteps.InIacetalishydrolyzedtoacetoneandadihydroxycarboxylic一CH?protonationCH2CO2H#Chapter23#Chapter23Inthesecondsetofsteps,thedihydroxycarboxyl23.59 Thisproblembecomeseasierifyoudrawthestarproduct.640Chapter23#Chapter2323.60#Chapter23h3c：JCOqCHeClaisercondercoch3.c=cco2ch3conjugateadditionofh3c：-#Chapter23#Chapter2323.6123.62protonation矽/C、H3c2rHH3C.additionHN(CH3)2ofamine