Methodwww.mywife.cc

fourtheditionORGANICCHEMISTRYFrancisA.
CareyUniversityofVirginiaBostonBurrRidge,ILDubuque,IAMadison,WINewYorkSanFranciscoSt.
LouisBangkokBogotáCaracasLisbonLondonMadridMexicoCityMilanNewDelhiSeoulSingaporeSydneyTaipeiTorontoORGANICCHEMISTRY,FOURTHEDITIONCopyright2000,1996,1992,1987byTheMcGraw-HillCompanies,Inc.
Allrightsreserved.
PrintedintheUnitedStatesofAmerica.
ExceptaspermittedundertheUnitedStatesCopyrightActof1976,nopartofthispublicationmaybereproducedordistributedinanyformorbyanymeans,orstoredinadatabaseorretrievalsystem,withoutthepriorwrittenpermissionofthepublisher.
Thisbookisprintedonacid-freepaper.
123457890VNH/VNH9098765432109ISBN0-07-290501-8Vicepresidentandeditorialdirector:KevinT.
KanePublisher:JamesM.
SmithSponsoringeditor:KentA.
PetersonDevelopmentaleditor:TerranceStantonEditorialassistant:JenniferBensinkSeniormarketingmanager:MartinJ.
LangeSeniormarketingassistant:TamiPetscheSeniorprojectmanager:PeggyJ.
SelleSeniorproductionsupervisor:SandraHahnDesigner:K.
WayneHarmsPhotoresearchcoordinator:JohnC.
LelandSeniorsupplementcoordinator:DavidA.
WelshCompositor:GTSGraphics,Inc.
Typeface:10/12TimesRomanPrinter:VonHoffmannPress,Inc.
Cover/interiordesigner:JamieO'NealPhotoresearch:MaryReegPhotoResearchThecreditssectionforthisbookbeginsonpageC-1andisconsideredanextensionofthecopyrightpage.
LibraryofCongressCataloging-in-PublicationDataCarey,FrancisA.
Organicchemistry/FrancisA.
Carey.
—4thed.
p.
cm.
Includesindex.
ISBN0-07-290501-8—ISBN0-07-117499-0(ISE)1.
Chemistry,Organic.
I.
Title.
QD251.
2.
C3642000547—dc2199-045791CIPINTERNATIONALEDITIONISBN0-07-117499-0Copyright2000.
ExclusiverightsbyTheMcGraw-HillCompanies,Inc.
formanufactureandexport.
Thisbookcannotbere-exportedfromthecountrytowhichitisconsignedbyMcGraw-Hill.
TheInternationalEditionisnotavailableinNorthAmerica.
www.
mhhe.
comMcGraw-HillHigherEducationADivisionofTheMcGraw-HillCompaniesABOUTTHEAUTHORFrancisA.
CareyisanativeofPennsylvania,educatedinthepublicschoolsofPhiladelphia,atDrexelUniver-sity(B.
S.
inchemistry,1959),andatPennState(Ph.
D.
1963).
FollowingpostdoctoralworkatHarvardandmil-itaryservice,hejoinedthechemistryfacultyoftheUni-versityofVirginiain1966.
Withhisstudents,ProfessorCareyhaspublishedover40researchpapersinsyntheticandmechanisticorganicchemistry.
Heiscoauthor(withRichardJ.
Sund-berg)ofAdvancedOrganicChemistry,atwo-volumetreatmentdesignedforgraduatestudentsandadvancedundergraduates,and(withRobertC.
Atkins)ofOrganicChemistry:ABriefCourse,anintroductorytextfortheone-semesterorganiccourse.
Since1993,ProfessorCareyhasbeenamemberoftheCommitteeofExaminersoftheGraduateRecordExaminationinChemistry.
Notonlydoeshegettopar-ticipateinwritingtheChemistryGRE,buttheannualworkingmeetingsprovideastimulatingenvironmentforsharingideasaboutwhatshould(andshouldnot)betaughtincollegechemistrycourses.
ProfessorCarey'smaininterestshiftedfromresearchtoundergraduateeducationintheearly1980s.
Heregularlyteachesbothgeneralchemistryandorganicchemistrytoclassesofover300students.
Heenthusi-asticallyembracesapplicationsofelectronicmediatochemistryteachingandseesmultimediapresentationsasthewaveofthepresent.
FrankandhiswifeJill,whoisateacher/directorofapreschoolandachurchorganist,aretheparentsofthreegrownsonsandthegrandparentsofRiyadandAva.
ixBRIEFCONTENTSPrefacexxvIntroduction11CHEMICALBONDING72ALKANES533CONFORMATIONSOFALKANESANDCYCLOALKANES894ALCOHOLSANDALKYLHALIDES1265STRUCTUREANDPREPARATIONOFALKENES:ELIMINATIONREACTIONS1676REACTIONSOFALKENES:ADDITIONREACTIONS2087STEREOCHEMISTRY2598NUCLEOPHILICSUBSTITUTION3029ALKYNES33910CONJUGATIONINALKADIENESANDALLYLICSYSTEMS36511ARENESANDAROMATICITY39812REACTIONSOFARENES:ELECTROPHILICAROMATICSUBSTITUTION44313SPECTROSCOPY48714ORGANOMETALLICCOMPOUNDS54615ALCOHOLS,DIOLS,ANDTHIOLS57916ETHERS,EPOXIDES,ANDSULFIDES61917ALDEHYDESANDKETONES:NUCLEOPHILICADDITIONTOTHECARBONYLGROUP65418ENOLSANDENOLATES70119CARBOXYLICACIDS73620CARBOXYLICACIDDERIVATIVES:NUCLEOPHILICACYLSUBSTITUTION77421ESTERENOLATES83122AMINES85823ARYLHALIDES91724PHENOLS93925CARBOHYDRATES97226LIPIDS101527AMINOACIDS,PEPTIDES,ANDPROTEINS.
NUCLEICACIDS1051APPENDIX1PHYSICALPROPERTIESA-1APPENDIX2ANSWERSTOIN-TEXTPROBLEMSA-9APPENDIX3LEARNINGCHEMISTRYWITHMOLECULARMODELS:UsingSpartanBuildandSpartanViewA-64GLOSSARYG-1CREDITSC-1INDEXI-1PREFACExxvPHILOSOPHYFromitsrsteditionthroughthis,itsfourth,OrganicChemistryhasbeendesignedtomeettheneedsofthe"mainstream,"two-semester,undergraduateorganicchemistrycourse.
Ithasevolvedasthoseneedshavechanged,butitsphilosophyremainsthesame.
Theover-archingthemeisthatorganicchemistryisnotonlyaninterestingsubject,butalsoalogicalone.
Itislogicalbecauseitstopicscanbeconnectedinasteadypro-gressionfromsimpletocomplex.
Ourapproachhasbeentorevealthelogicoforganicchemistrybybeingselectiveinthetopicswecover,aswellasthoroughandpatientindevelopingthem.
Teachingatalllevelsisundergoingrapidchange,especiallyinapplyingpowerfultoolsthatexploitthegraphicscapabilityofpersonalcomputers.
Organicchemistryhasalwaysbeenthemostgraphicalofthechemicalsciencesandiswellpositionedtobenetsig-nicantlyfromthesetools.
Consistentwithourphiloso-phy,thiseditionusescomputergraphicstoenhancethecorematerial,tomakeitmorevisual,andmoreunder-standable,butinawaythatincreasesneithertheamountofmaterialnoritslevel.
ORGANIZATIONThecentralmessageofchemistryisthatthepropertiesofasubstancecomefromitsstructure.
Whatislessobvious,butverypowerful,isthecorollary.
Someonewithtraininginchemistrycanlookatthestructureofasubstanceandtellyoualotaboutitsproperties.
Organicchemistryhasalwaysbeen,andcontinuestobe,thebranchofchemistrythatbestconnectsstructurewithproperties.
Thistexthasastrongbiastowardstructure,andthiseditionbenetsfromtheavailabilityofversa-tilenewtoolstohelpusunderstandthatstructure.
Thetextisorganizedtoowlogicallyandstepbystepfromstructuretopropertiesandbackagain.
Asthelistofchaptertitlesreveals,theorganizationisaccord-ingtofunctionalgroups—structuralunitswithinamol-eculemostresponsibleforaparticularproperty—becausethatistheapproachthatpermitsmoststudentstograspthematerialmostreadily.
Studentsretainthematerialbest,however,iftheyunderstandhoworganicreactionstakeplace.
Thus,reactionmechanismsarestressedearlyandoften,butwithinafunctionalgroupframework.
Acloserexaminationofthechaptertitlesrevealsthecloselinkbetweenafunctionalgroupclass(Chapter20,CarboxylicAcidDerivatives)andareactiontype(NucleophilicAcylSubstitution),forexample.
Itisverysatisfyingtoseestudentswhoenteredthecoursebelievingtheyneededtomemorizeeverythingprogresstothepointofthinkingandreasoningmechanistically.
Someoftheimportantstagesinthisapproachareasfollows:Therstmechanismthestudentsencounter(Chap-ter4)describestheconversionofalcoholstoalkylhalides.
Notonlyisthisausefulfunctional-grouptransformation,butitsrststepproceedsbythesimplestmechanismofall—protontransfer.
Theoverallmechanismprovidesforanearlyrein-forcementofacid-basechemistryandanearlyintroductiontocarbocationsandnucleophilicsub-stitution.
Chapter5continuesthechemistryofalcoholsandalkylhalidesbyshowinghowtheycanbeusedtopreparealkenesbyeliminationreactions.
Here,thestudentsseeasecondexampleoftheformationofcarbocationintermediatesfromalcohols,butinthiscase,thecarbocationtravelsadifferentpath-waytoadifferentdestination.
ThealkenespreparedinChapter5arestudiedagaininChapter6,thistimewithaneyetowardtheirownchemicalreactivity.
WhatthestudentslearnedaboutcarbocationsinChapters4and5servesthemwellinunderstandingthemechanismsofthereactionsofalkenesinChapter6.
Likewise,themechanismofnucleophilicadditiontothecarbonylgroupofaldehydesandketonesdescribedinChapter17setsthestageforaldolcon-densationinChapter18,estericationofcarboxylicacidsinChapter19,nucleophilicacylsubstitutioninChapter20,andestercondensationinChapter21.
xxviPREFACETHESPARTANINTEGRATIONThethirdeditionofthistextbrokenewgroundwithitsemphasisonmolecularmodeling,includingtheadditionofmorethan100exercisesofthemodel-buildingtype.
This,thefourthedition,movestothenextlevelofmod-eling.
GwendolynandAlanShusterman's1997JournalofChemicalEducationarticle"TeachingChemistrywithElectronDensityModels"describedhowmodelsshow-ingtheresultsofmolecularorbitalcalculations,espe-ciallyelectrostaticpotentialmaps,couldbeusedeffec-tivelyinintroductorycourses.
ThesoftwareusedtocreatetheShustermans'modelswasSpartan,aproductofWavefunction,Inc.
Inanutshell,thebeautyofelectrostaticpotentialmapsistheirabilitytodisplaythechargedistributioninamolecule.
Atthemostfundamentallevel,theforcesthatgovernstructureandpropertiesinorganicchemistryaretheattractionsbetweenoppositechargesandtherepulsionsbetweenlikecharges.
Wewerethereforeopti-misticthatelectrostaticpotentialmapsheldgreatpromiseforhelpingstudentsmaketheconnectionbetweenstructure,especiallyelectronicstructure,andproperties.
Evenatanearlystagewerealizedthattwomainconsiderationshadtoguideourefforts.
Anintegratedapproachwasrequired.
Tobeeffec-tive,Spartanmodelsandtheinformationtheypro-videmustbewoveninto,notaddedto,thebook'score.
Thelevelofthecoveragehadtoremainthesame.
Spartanisversatile.
Weusedthesamesoftwarepackagetodevelopthiseditionthatisusedinresearchlaboratoriesworldwide.
Itwasessentialthatwelimitourselvestoonlythosefeaturesthatclariedaparticularpoint.
Organicchemistryischallengingenough.
Wedidn'tneedtomakeitmoredifcult.
Ifweweretoerr,itwouldthere-forebebettertoerronthesideofcaution.
Athirdconsiderationsurfacedsoonaftertheworkbegan.
StudentaccesstoSpartanwouldbeessential.
Nothingcouldhelpstudentsconnectwithmolec-ularmodelingbetterthanowningthesamesoft-wareusedtoproducethetextor,evenbetter,soft-warethatallowedthemnotonlytoviewmodelsfromthetext,butalsotomaketheirown.
Allofthisledtoafruitfulandstimulatingcollab-orationwithDr.
WarrenHehre,aleadingtheoreticalchemistandthefounder,president,andCEOofWave-function,Inc.
Warrenwasenthusiasticabouttheprojectandagreedtoactivelyparticipateinit.
HeandAlanShustermanproducedaCDtailoredspecicallytoNEWINTHISEDITIONALL-NEWILLUSTRATIONSAllgureswereredrawntoconveyvisualconceptsclearlyandforcefully.
Inad-dition,theauthorcreatedanumberofnewimagesusingtheSpartanmolecularmodelingapplication.
Nowstudentscanviewelectrostaticpotentialmapstoseethechargedistributionofamoleculeinvividcolor.
Thesestrikingimagesaffordtheinstructorapowerfulmeanstoleadstudentstoabetterunder-standingoforganicmolecules.
FULLSPARTANIMAGEINTEGRATIONTheSpartan-generatedimagesareimpressiveintheirownright,butforteachingpurposestheyaremosteffectivewhentheyarecloselyalignedwiththetextcontent.
Becausetheauthorpersonallygeneratedtheimagesashewrotethisedition,themolecularmodelsarefullyintegratedwithtext,andtheeducationalvalueismaximized.
Additionally,iconsdirectstudentstospecicapplicationsofeithertheSpartanVieworSpartanBuildprogram,foundontheaccompanyingCD-ROM.
Appendix3providesacompleteguidetotheLearningByModelingCD-ROM.
ALL-NEWSPECTRAChapter13,Spectroscopy,washeavilyrevised,withrewrittensectionsonNMRandwithalltheNMRspectrageneratedonahigh-eldinstrument.
IMPROVEDSUMMARIESTheend-of-chaptersum-mariesarerecastintoamoreopen,easier-to-readformat,inspiredbythepopularityoftheaccompany-ingsummarytables.
NEWDESIGNThiseditionsportsanewlook,withanemphasisonneatness,clarity,andcolorcarefullyusedtoheighteninterestandtocreatevisualcuesforimportantinformation.
PREFACExxviiaccompanyourtext.
WecallitLearningByModeling.
ItandOrganicChemistrytrulycomplementeachother.
ManyoftheproblemsinOrganicChemistryhavebeenwrittenexpresslyforthemodel-buildingsoftwareSpar-tanBuildthatformsonepartofLearningByModeling.
Anothertool,SpartanView,letsstudentsinspectmorethan250alreadyconstructedmodelsandanimations,ranginginsizefromhydrogentocarboxypeptidase.
WewerecarefultoincorporateSpartansoitwouldbeatrueamplierofthetextbook,notjustasastand-alonetoolthatstudentsmightormightnotuse,depend-ingontheinvolvementoftheirinstructor.
Thus,thecontentoftheCDprovidesvisual,three-dimensionalreinforcementoftheconceptscoveredontheprintedpage.
TheSpartanViewiconinvitesstudentstoviewamoleculeoranimationastheyarereadingthetext.
OpportunitiestouseSpartanBuildaresimilarlycorrelatedtothetextwithanicondirectingstudentstofurtherexploreaconceptorsolveamodeling-basedproblemwiththesoftware.
InadditiontoitsroleastheelectronicbackboneoftheCDcomponentandtheintegratedlearningapproach,theSpartansoftwaremakesavisibleimpactontheprintedpagesofthisedition.
IusedSpartanonmyowncomputertocreatemanyofthegures,pro-vidingstudentswithnumerousvisualexplorationsoftheconceptsofchargedistribution.
BIOLOGICALAPPLICATIONSANDTHEIRINTEGRATIONComprehensivecoverageoftheimportantclassesofbio-molecules(carbohydrates,lipids,aminoacids,peptides,proteins,andnucleicacids)appearsinChapters25–27.
Butbiologicalapplicationsaresuchanimportantpartoforganicchemistrythattheydeservemoreattentionthroughoutthecourse.
Wewereespeciallyalerttooppor-tunitiestointroducemorebiologicallyorientedmaterialtocomplementthatwhichhadalreadygrownsigni-cantlysincetherstedition.
Somespecicexamples:Thenewboxedessay"MethaneandtheBio-sphere"inChapter2combineselementsoforganicchemistry,biology,andenvironmentalsci-encetotellthestoryofwheremethanecomesfromandwhereitgoes.
Anewboxedessay,"AnEnzyme-CatalyzedNucleophilicSubstitutionofanAlkylHalide,"inChapter8makesadirectandsimpleconnectionbetweenSN2reactionsandbiochemistry.
Twonewboxedessays,"HowSweetItIs!
"inChapter25,and"GoodCholesterolBadCholes-terolWhat'stheDifference"inChapter26,covertopicsofcurrentinterestfromanorganicchemist'sperspective.
Thealready-numerousexamplesofenzyme-catalyzedorganicreactionsweresupplementedbyaddingbiologicalBaeyer-Villigeroxidationsandfumaricaciddehydrogenation.
Chapters25–27havebenetedsubstantiallyfromtheSpartanconnection.
Wereplacedmanyoftheartist-renderedstructuraldrawingsofcomplexbiomoleculesfromearliereditionswithaccuratemodelsgeneratedfromimportedcrystallographicdata.
Theseinclude:maltose,cellobiose,andcelluloseinChapter25triacylglycerolsinChapter26alanylglycine,leucineenkephalin,apleated-sheet,an-helix,carboxypeptidase,myoglobin,DNA,andphenylalaninetRNAinChapter27AlloftheseareincludedonLearningByModel-ing,whereyoucanviewthemaswire,ball-and-spoke,tube,orspace-llingmodelswhilerotatingtheminthreedimensions.
BoththetextandLearningByModelingincludeotherstructuresofbiologicalinterestincluding:aspace-llingmodelofamicelle(Chapter19)electrostaticpotentialmapsofthe20commonaminoacidsshowingjusthowdifferentthevari-oussidechainsare(Chapter27)SPECTROSCOPYBecauseitoffersanintegratedtreatmentofnuclearmag-neticresonance(NMR),infrared(IR),andultraviolet-visible(UV-VIS)spectroscopy,andmassspectrometry(MS),Chapter13isthelongestinthetext.
Itisalsothechapterthatreceivedthemostattentioninthisedition.
AllofthesectionsdealingwithNMRwereextensivelyrewritten,alloftheNMRspectrawerenewlyrecordedonahigh-eldinstrument,andallofthetextgureswereproduceddirectlyfromtheelectronicdatales.
Likewise,theIRandUV-VISsectionsofChapter13wererevisedandalloftheIRspectrawererecordedespeciallyforthistext.
AfterbeingrstpresentedinChapter13,spec-troscopyisthenintegratedintothetopicsthatfollowit.
Thefunctional-groupchapters,15,16,17,19,20,22,xxviiiPREFACEand24,allcontainspectroscopysectionsaswellasexamplesandproblemsbasedondisplayspectra.
INTEGRATIONOFTOPICSToooften,intoomanycourses(andnotjustinorganicchemistry),toomanyinterestingtopicsnevergetcov-eredbecausetheyarerelegatedtotheendofthetextas"specialtopicchapters"that,unfortunately,fallbythewaysideastheendofthetermapproaches.
Wehave,fromthebeginningandwitheachsucceedingedition,lookedforopportunitiestointegratethemostimportantofthese"special"topicsintothecorematerial.
Iampleasedwiththeresults.
Typically,thisintegrationisaccomplishedbybreakingatopicintoitscomponentelementsandlinkingeachofthoseelementstooneormoreconceptuallyrelatedcoretopics.
Thereis,forexample,noend-of-textchapterenti-tled"HeterocyclicCompounds.
"Rather,heteroatomsaredenedinChapter1andnonaromaticheterocycliccompoundsintroducedinChapter3;heterocyclicaro-maticcompoundsareincludedinChapter11,andtheirelectrophilicandnucleophilicaromaticsubstitutionreac-tionsdescribedinChapters12and23,respectively.
Het-erocycliccompoundsappearinnumerouswaysthrough-outthetextandthebiologicalroleoftwoclassesofthem—thepurinesandpyrimidines—featurespromi-nentlyinthediscussionofnucleicacidsinChapter27.
Theeconomicimpactofsyntheticpolymersistoogreattosendthemtotheendofthebookasaseparatechapterortogroupthemwithbiopolymers.
Weregardpolymersasanaturalpartoforganicchemistryandpayattentiontothemthroughoutthetext.
ThepreparationofvinylpolymersisdescribedinChapter6,polymerste-reochemistryinChapter7,dienepolymersinChapter10,Ziegler–NattacatalysisinChapter14,andconden-sationpolymersinChapter20.
INTEGRATINGTHECHEMISTRYCURRICULUMIalwaysthoughtthatthegeneralchemistrycoursewouldbeimprovedifmoreorganicchemiststaughtit,andhavedonejustthatmyselfforthepastnineyears.
Inowseethatjustasgeneralchemistrycanbenetfromtheperspectivethatanorganicchemistbringstoit,socantheteachingandlearningoforganicchemistrybeimprovedbymakingthetransitionfromgeneralchem-istrytoorganicsmoother.
Usuallythisismoreamatterofstyleandterminologythancontent—anincrementalratherthanaradicalchange.
Istartedmakingsuchchangesinthethirdeditionandcontinuehere.
Iliked,forexample,writingthenewboxedessay"Laws,Theories,andtheScienticMethod"andplacingitinChapter6.
Thescienticmethodisonethingthateveryonewhotakesacollege-levelchemistrycourseshouldbefamiliarwith,butmostaren't.
ItnormallyappearsinChapter1ofgeneralchemistrytexts,beforethestudentshaveenoughfactualknowledgetoreallyunder-standit,andit'srarelymentionedagain.
Bythetimeourorganicchemistrystudentsgetto"Laws,Theories,andtheScienticMethod,"however,wehavetoldthemabouttheexperimentalobservationsthatledtoMarkovnikov'slaw,andhowourunderstandinghasprogressedtothelevelofabroadlyacceptedtheorybasedoncarbocationstability.
Itmakesanicestory.
Let'suseit.
FEWERTOPICSEQUALSMOREHELPBybeingselectiveinthetopicswecover,wecanincludemorematerialdesignedtohelpthestudentlearn.
Solvedsampleproblems:Inadditiontoagenerousnumberofend-of-chapterproblems,thetextincludesmorethan450problemswithinthechap-tersthemselves.
Ofthesein-chapterproblemsapproximatelyone-thirdaremultipartexercisesthatcontainadetailedsolutiontopart(a)outlin-ingthereasoningbehindtheanswer.
Summarytables:AnnotatedsummarytableshavebeenastapleofOrganicChemistryeversincethersteditionandhaveincreasedinnumbertomorethan50.
Wellreceivedbystudentsandfacultyalike,theyremainoneofthetext'sstrengths.
End-of-chaptersummaries:Ourexperiencewiththesummarytablespromptedustorecastthenarra-tivepartoftheend-of-chaptersummariesintoamoreopen,easier-to-readformat.
SUPPLEMENTSFortheStudentStudyGuideandSolutionsManualbyFrancisA.
CareyandRobertC.
Atkins.
Thisvaluablesupplementprovidessolutionstoallproblemsinthetext.
Morethansimplyprovidinganswers,mostsolutionsguidethestu-dentwiththereasoningbehindeachproblem.
Inaddi-tion,eachchapteroftheStudyGuideandSolutionsManualconcludeswithaSelf-Testdesignedtoassessthestudent'smasteryofthematerial.
OnlineLearningCenterAtwww.
mhhe.
com/carey,thiscomprehensive,exclusiveWebsiteprovidesawealthofelectronicresourcesforPREFACExxixinstructorsandstudentsalike.
Contentincludestutorials,problem-solvingstrategies,andassessmentexercisesforeverychapterinthetext.
LearningByModelingCD-ROMIncollaborationwithWavefunction,wehavecreatedacross-functionCD-ROMthatcontainsanelectronicmodel-buildingkitandarichcollectionofanimationsandmolecularmodelsthatrevealtheinterplaybetweenelectronicstructureandreactivityinorganicchemistry.
Packagedfreewiththetext,LearningByModel-inghastwocomponents:SpartanBuild,auser-friendlyelectronictoolboxthatletsyoubuild,examine,andeval-uateliterallythousandsofmolecularmodels;andSpar-tanView,anapplicationwithwhichyoucanviewandexaminemorethan250molecularmodelsandanima-tionsdiscussedinthetext.
Inthetextbook,iconspointthewaytowhereyoucanusethesestate-of-the-artmol-ecularmodelingapplicationstoexpandyourunder-standingandsharpenyourconceptualskills.
Thisedi-tionofthetextcontainsnumerousproblemsthattakeadvantageoftheseapplications.
Appendix3providesacompleteguidetousingtheCD.
FortheInstructorOverheadTransparencies.
Thesefull-colortransparen-ciesofillustrationsfromthetextincludereproductionsofspectra,orbitaldiagrams,keytables,computer-generatedmolecularmodels,andstep-by-stepreactionmechanisms.
TestBank.
Thiscollectionof1000multiple-choicequestions,preparedbyProfessorBruceOsterbyoftheUniversityofWisconsin–LaCrosse,isavailabletoadoptersinprint,Macintosh,orWindowsformat.
VisualResourceLibrary.
ThisinvaluablelectureaidprovidestheinstructorwithalltheimagesfromthetextbookonaCD-ROM.
ThePowerPointformatenableseasycustomizationandformattingoftheimagesintothelecture.
TheOnlineLearningCenter,describedinthepre-vioussection,hasspecialfeaturesforinstructors,includ-ingquizcapabilities.
PleasecontactyourMcGraw-Hillrepresentativeforadditionalinformationconcerningthesesupple-ments.
ACKNOWLEDGMENTSxxxiYoumayhavenoticedthatthisprefaceisalmostentirely"we"and"our,"not"I"and"my.
"ThatisbecauseOrganicChemistryis,andalwayshasbeen,ateameffort.
Fromthersteditiontothisone,theeditorialandproductionstaffsatWCB/McGraw-Hillhavebeencom-mittedtocreatinganaccurate,interesting,student-orientedtext.
SpecialthanksgotoKentPeterson,TerryStanton,andPeggySellefortheirprofessionalism,skill,andcooperativespirit.
LindaDavolinotonlycopyeditedthemanuscriptbutofferedvaluableadviceaboutstyleandpresentation.
GTSGraphicshadthecriticaljobofconvertingthecopy-editedmanuscripttoarealbook.
OurcontacttherewasHeatherStratton;herenthusiasmfortheprojectprovidedusanunusualamountoffree-domtone-tunethetext.
IhavealreadymentionedthevitalroleplayedbyWarrenHehreandAlanShustermaninintegratingSpar-tanintothisedition.
Iamgratefulfortheirgenerosityingivingtheirtime,knowledge,andsupporttothisproj-ect.
IalsothankDr.
MichalSabatoftheUniversityofVirginiaforhisassistanceinmyownmodelingefforts.
AlloftheNMRandIRspectrainthiseditionwererecordedattheDepartmentofChemistryofJamesMadisonUniversitybytwoundergraduatestudents,Jef-freyCrossandKarinHamburger,undertheguidanceofThomasGallaher.
Weareindebtedtothemfortheirhelp.
Again,asinthethreepreviouseditions,Dr.
RobertC.
Atkinshasbeenindispensable.
BobisthedrivingforcebehindtheStudyGuideandSolutionsManualthataccompaniesthistext.
Heismuchmorethanthat,though.
Hereadsandcritiqueseverypageoftheman-uscriptandeverypageoftworoundsofproofs.
Itrusthisjudgmentcompletelywhenhesuggestshowtosim-plifyapointormakeitclearer.
Mostofall,heisagreatfriend.
Thistexthasbenetedfromthecommentsofferedbyalargenumberofteachersoforganicchemistrywhorevieweditatvariousstagesofitsdevelopment.
Iappre-ciatetheirhelp.
TheyincludeReviewersfortheFourthEditionJenniferAdamski,OldDominionUniversityJeffreyB.
Arterburn,NewMexicoStateUniversityStevenBachrach,TrinityUniversityJaredA.
Butcher,Jr.
,OhioUniversityBarryCarpenter,CornellUniversityPasqualeR.
DiRaddo,FerrisStateUniversityJillDiscordia,LeMoyneCollegeWilliamA.
Donaldson,MarquetteUniversityMarkForman,St.
Joseph'sUniversityWarrenGiering,BostonUniversityBenjaminGross,UniversityofTennessee–ChattanoogaR.
J.
Hargrove,MercerUniversityE.
AlexanderHill,UniversityofWisconsin–MilwaukeeShawnHitchcock,IllinoisStateUniversityL.
A.
Hull,UnionCollegeColleenKelley,NorthernArizonaUniversityBrendaKesler,SanJoseStateUniversityC.
A.
Kingsbury,UniversityofNebraska–LincolnFrancisM.
Klein,CreightonUniversityPaulM.
Lahti,UniversityofMassachusetts–AmherstRitaS.
Majerle,SouthDakotaStateUniversityMichaelMillam,PhoenixCollegeTyraMontgomery,UniversityofHouston–DowntownRichardNarske,AugustanaUniversityMichaelA.
Nichols,JohnCarrollUniversityBruceE.
Norcross,SUNY–BinghamtonCharlesA.
Panetta,UniversityofMississippiMichaelJ.
Panigot,ArkansasStateUniversityJoePavelites,WilliamWoodsCollegeTyRedd,SouthernUtahUniversityCharlesRose,UniversityofNevadaSuzanneRuder,VirginiaCommonwealthUniversityChristineM.
Russell,CollegeofDuPageDennisA.
Sardella,BostonCollegeJaniceG.
Smith,Mt.
HolyokeCollegeTamiI.
Spector,UniversityofSanFranciscoKenTurnbull,WrightStateUniversityCliffordM.
Utermoehlen,USAFAcademyCurtWentrup,UniversityofQueenslandS.
D.
Worley,AuburnUniversityReviewersfortheThirdEditionEdwardAlexander,SanDiegoMesaCollegeRonaldBaumgarten,UniversityofIllinois–ChicagoBarryCarpenter,CornellUniversityJohnCochran,ColgateUniversityxxxiiACKNOWLEDGMENTSI.
G.
Csizmadia,UniversityofTorontoLorrainDang,CityCollegeofSanFranciscoGrahamDarling,McGillUniversityDebraDilner,U.
S.
NavalAcademyCharlesDougherty,LehmanCollege,CUNYFillmoreFreeman,UniversityofCalifornia–IrvineCharlesGarner,BaylorUniversityRainerGlaser,UniversityofMissouri–ColumbiaRonGratz,MaryWashingtonCollegeScottGronert,SanFranciscoStateUniversityDanielHarvey,UniversityofCalifornia–SanDiegoJohnHenderson,JacksonCommunityCollegeStephenHixson,UniversityofMassachusetts–AmherstC.
A.
Kingsbury,UniversityofNebraska–LincolnNicholasLeventis,UniversityofMissouri–RollaKwang-TingLiu,NationalTaiwanUniversityPeterLivant,AuburnUniversityJ.
E.
Mulvaney,UniversityofArizonaMarcoPagnotta,BarnardCollegeMichaelRathke,MichiganStateUniversityCharlesRose,UniversityofNevada–RenoRonaldRoth,GeorgeMasonUniversityMartinSaltzman,ProvidenceCollegePatriciaThorstenson,UniversityoftheDistrictofColumbiaMarcusTius,UniversityofHawaiiatManoaVictoriaUkachukwu,RutgersUniversityThomasWaddell,UniversityofTennessee–ChattanoogaGeorgeWahl,Jr.
,NorthCarolinaStateUniversityJohnWasacz,ManhattanCollegeFinally,Ithankmyfamilyfortheirlove,help,andencouragement.
The"bigve"remainthesame:mywifeJill,oursonsAndy,Bob,andBill,anddaughter-in-lawTasneem.
Theyhavebeenjoinedbythe"littletwo,"ourgrandchildrenRiyadandAva.
Comments,suggestions,andquestionsarewel-come.
Previouseditionsproducedalargenumberofe-mailmessagesfromstudents.
Ifoundthemveryhelp-fulandinviteyoutocontactmeat:fac6q@unix.
mail.
virginia.
edu.
FrancisA.
CareyAGUIDETOUSINGTHISTEXTThefollowingpagesprovideawalk-throughofthekeyfeaturesofthistext.
Everyelementinthisbookhasapurposeandservestheoverallgoalofleadingstudentstoatrueunderstandingoftheprocessesinorganicchemistry.
xxxiiiINTEGRATEDTEXTANDVISUALSWithAll-newFiguresBecausevisualizationissoimportanttounderstanding,illustrationsworkhand-in-handwithtexttoconveyinfor-mation.
TheauthorgeneratedmanyofthegureshimselfashewrotethetextusingSpartansoftware,sothatimagesarefullycoordinatedwiththetext.
EFFECTIVEORGANIZATIONOFFUNCTIONALGROUPSReactionmechanismsarestressedearlyandoften,butwithinafunctionalframework.
Forexample,Chapter4istherstchaptertocoverafunctionalgroup(alcoholsandalkylhalides)butitintroducesmechanismsimultaneously.
protoninvolvedmustbebondedtoanelectronegativeelement,usuallyoxygenornitro-gen.
ProtonsinC±Hbondsdonotparticipateinhydrogenbonding.
Thusuoroethane,eventhoughitisapolarmoleculeandengagesindipole—dipoleattractions,doesnotformhydrogenbondsand,therefore,hasalowerboilingpointthanethanol.
Hydrogenbondingcanbeexpectedinmoleculesthathave±OHor±NHgroups.
Individualhydrogenbondsareabout10—50timesweakerthantypicalcovalentbonds,buttheireffectscanbesignicant.
Morethanotherdipole—dipoleattractiveforces,inter-molecularhydrogenbondsarestrongenoughtoimposearelativelyhighdegreeofstruc-turalorderonsystemsinwhichtheyarepossible.
AswillbeseeninChapter27,thethree-dimensionalstructuresadoptedbyproteinsandnucleicacids,theorganicmole-culesoflife,aredictatedbypatternsofhydrogenbonds.
PROBLEM4.
5Theconstitutionalisomerofethanol,dimethylether(CH3OCH3),isagasatroomtemperature.
Suggestanexplanationforthisobservation.
Table4.
1liststheboilingpointsofsomerepresentativealkylhalidesandalcohols.
Whencomparingtheboilingpointsofrelatedcompoundsasafunctionofthealkylgroup,wendthattheboilingpointincreaseswiththenumberofcarbonatoms,asitdoeswithalkanes.
4.
5PhysicalPropertiesofAlcoholsandAlkylHalides:IntermolecularForces131TABLE4.
1BoilingPointsofSomeAlkylHalidesandAlcoholsNameofalkylgroupMethylEthylPropylPentylHexylFormulaCH3XCH3CH2XCH3CH2CH2XCH3(CH2)3CH2XCH3(CH2)4CH2XFunctionalgroupXandboilingpoint,C(1atm)XF783236592XCl241247108134XBr33871129155XI4272103157180XOH657897138157FIGURE4.
4Hydrogenbondinginethanolinvolvestheoxygenofonemoleculeandtheprotonofan±OHgroupofanother.
Hydrogenbondingismuchstrongerthanmostothertypesofdipole—dipoleattractiveforces.
Hydrogenbondsbetween±OHgroupsarestrongerthanthosebetween±NHgroups,asacomparisonoftheboilingpointsofwater(H2O,100°C)andammonia(NH3,33°C)demonstrates.
Foradiscussionconcerningtheboilingpointbehaviorofalkylhalides,seetheJanuary1988issueoftheJournalofChemicalEducation,pp.
62—64.
CHAPTER4ALCOHOLSANDALKYLHALIDESOurrstthreechaptersestablishedsomefundamentalprinciplesconcerningthestructureoforganicmolecules.
Inthischapterwebeginourdiscussionoforganicchemicalreactionsbydirectingattentiontoalcoholsandalkylhalides.
Thesetworankamongthemostusefulclassesoforganiccompoundsbecausetheyoftenserveasstartingmaterialsforthepreparationofnumerousotherfamilies.
Tworeactionsthatleadtoalkylhalideswillbedescribedinthischapter.
Bothillus-tratefunctionalgrouptransformations.
Intherst,thehydroxylgroupofanalcoholisreplacedbyhalogenontreatmentwithahydrogenhalide.
Inthesecond,reactionwithchlorineorbrominecausesoneofthehydrogensubstituentsofanalkanetobereplacedbyhalogen.
Bothreactionsareclassiedassubstitutions,atermthatdescribestherelationshipbetweenreactantsandproductsonefunctionalgroupreplacesanother.
Inthischapterwegobeyondtherelationshipofreactantsandproductsandconsiderthemechanismofeachreaction.
Amechanismattemptstoshowhowstartingmaterialsareconvertedintoproductsduringachemicalreaction.
Whiledevelopingthesethemesofreactionandmechanism,wewillalsousealco-holsandalkylhalidesasvehiclestoextendtheprinciplesofIUPACnomenclature,con-R±HAlkaneX2HalogenR±XAlkylhalideH±XHydrogenhalideR±OHAlcoholH±XHydrogenhalideR±XAlkylhalideH±OHWater126xxxivAGUIDETOUSINGTHISTEXTLEARNINGBYMODELINGAFullCorrelationNotonlycanstudentsviewmolecularmodelswhileusingthebook,butwiththefreeCD-ROMthataccompaniesthetext,theyhaveaccesstothesoftwarethatwasusedtocre-atetheimages.
WiththeSpartanViewandSpartanBuildsoftware,studentscanviewmodelsfromthetextandalsomaketheirown.
TheSpartanViewiconidentiesmol-eculesandanimationsthatcanbeseenontheCD.
Appen-dix3providesacompletetutorialguidetotheCD.
LEARNINGBYMODELINGAnActiveProcessManyoftheproblemsinthiseditionofthetexthavebeenexpresslywrittentoinvolveuseoftheSpartanBuildsoft-wareontheLearningByModelingCD-ROM.
Studentsdis-covertheconnectionbetweenstructureandpropertiesbyactuallybuildingmoleculesontheirown.
TheSpartanBuildicondirectsthemwhentousethistool.
Boththeisotacticandthesyndiotacticformsofpolypropyleneareknownasstereoreg-ularpolymers,becauseeachischaracterizedbyaprecisestereochemistryatthecarbonatomthatbearsthemethylgroup.
Thereisathirdpossibility,showninFigure7.
17c,whichisdescribedasatactic.
Atacticpolypropylenehasarandomorientationofitsmethylgroups;itisnotastereoregularpolymer.
PolypropylenechainsassociatewithoneanotherbecauseofattractivevanderWaalsforces.
Theextentofthisassociationisrelativelylargeforisotacticandsyndio-tacticpolymers,becausethestereoregularityofthepolymerchainspermitsefcientpack-ing.
Atacticpolypropylene,ontheotherhand,doesnotassociateasstrongly.
Ithasalowerdensityandlowermeltingpointthanthestereoregularforms.
Thephysicalprop-ertiesofstereoregularpolypropylenearemoreusefulformostpurposesthanthoseofatacticpolypropylene.
Whenpropeneispolymerizedunderfree-radicalconditions,thepolypropylenethatresultsisatactic.
CatalystsoftheZiegler—Nattatype,however,permitthepreparationofeitherisotacticorsyndiotacticpolypropylene.
Weseehereanexampleofhowproperchoiceofexperimentalconditionscanaffectthestereochemicalcourseofachemicalreactiontotheextentthatentirelynewmaterialswithuniquepropertiesresult.
7.
15StereoregularPolymers289(a)Isotacticpolypropylene(b)Syndiotacticpolypropylene(c)AtacticpolypropyleneFIGURE7.
17Poly-mersofpropene.
Themainchainisshowninazigzagconformation.
Everyothercarbonbearsamethylsub-stituentandisastereogeniccenter.
(a)Allthemethylgroupsareonthesamesideofthecarbonchaininisotac-ticpolypropylene.
(b)Methylgroupsalternatefromonesidetotheotherinsyndio-tacticpolypropylene.
(c)Thespatialorientationofthemethylgroupsisrandominatacticpolypropylene.
16.
2STRUCTUREANDBONDINGINETHERSANDEPOXIDESBondinginethersisreadilyunderstoodbycomparingetherswithwaterandalcohols.
VanderWaalsstraininvolvingalkylgroupscausesthebondangleatoxygentobelargerinethersthanalcohols,andlargerinalcoholsthaninwater.
Anextremeexampleisdi-tert-butylether,wheresterichindrancebetweenthetert-butylgroupsisresponsibleforadramaticincreaseintheC±O±Cbondangle.
Typicalcarbon—oxygenbonddistancesinethersaresimilartothoseofalcohols(142pm)andareshorterthancarbon—carbonbonddistancesinalkanes(153pm).
AnetheroxygenaffectstheconformationofamoleculeinmuchthesamewaythataCH2unitdoes.
Themoststableconformationofdiethyletheristheall-staggeredanticonformation.
Tetrahydropyranismoststableinthechairconformation—afactthathasanimportantbearingonthestructuresofmanycarbohydrates.
Incorporatinganoxygenatomintoathree-memberedringrequiresitsbondangletobeseriouslydistortedfromthenormaltetrahedralvalue.
Inethyleneoxide,forexam-ple,thebondangleatoxygenis61.
5°.
Thusepoxides,likecyclopropanes,arestrained.
Theytendtoundergoreactionsthatopenthethree-memberedringbycleavingoneofthecarbon—oxygenbonds.
PROBLEM16.
2Theheatsofcombustionof1,2-epoxybutane(2-ethyloxirane)andtetrahydrofuranhavebeenmeasured:oneis2499kJ/mol(597.
8kcal/mol);theotheris2546kJ/mol(609.
1kcal/mol).
Matchtheheatsofcombustionwiththerespectivecompounds.
Ethers,likewaterandalcohols,arepolar.
Diethylether,forexample,hasadipolemomentof1.
2D.
Cyclicethershavelargerdipolemoments;ethyleneoxideandtetrahy-drofuranhavedipolemomentsinthe1.
7-to1.
8-Drangeaboutthesameasthatofwater.
H2COCH2147pm144pmCOCCCOangle61.
5°angle59.
2°HHO105°Water108.
5°HCH3OMethanol112°CH3CH3ODimethylether132°OC(CH3)3(CH3)3CDi-tert-butylether16.
2StructureandBondinginEthersandEpoxides621UseLearningByModelingtomakemodelsofwater,methanol,dimethylether,anddi-tert-butylether.
Minimizetheirgeometries,andexaminewhathappenstotheC±O±Cbondangle.
ComparetheC±Obonddistancesindimethyletheranddi-tert-butylether.
AGUIDETOUSINGTHISTEXTxxxvLEARNINGBYMODELINGBuildBiomoleculesInthebiological-specicchapters,learningisonceagainenhancedbytheaccesstoSpartanmodelbuilding.
Carbo-hydrates,lipids,aminoacids,peptides,proteins,andnucleicacidbenetfromSpartan,andmanyforthisedi-tionweregeneratedfromimportedcrystallographicdata.
Andstudentscanviewmodelsofthe20commonaminoacidsonLearningByModeling,androtatetheminthreedimensions,orviewthemasball-and-spoke,tube,orspace-llingmodels.
LEARNINGBYMODELINGFromSpartantothePageNewinthisedition'sguresaremolecularmodelsthattheauthorgeneratedusingtheSpartanmodelingapplication.
Electrostaticpotentialmapsgiveavividlookatthechargedistributioninamolecule,showingtheforcesthatgovernstructureandpropertiesinorganicchemistry.
1.
10TheShapesofSomeSimpleMolecules27LEARNINGBYMODELINGAsearlyasthenineteenthcenturymanychemistsbuiltscalemodelsinordertobetterunderstandmolecularstructure.
Wecangainaclearerideaaboutthefeaturesthataffectstructureandreactivitywhenweexaminethethree-dimensionalshapeofamolecule.
SeveraltypesofmolecularmodelsareshownformethaneinFigure1.
7.
Probablythemostfamiliarareball-and-stickmodels(Figure1.
7b),whichdirectapproximatelyequalattentiontotheatomsandthebondsthatcon-nectthem.
Frameworkmodels(Figure1.
7a)andspace-llingmodels(Figure1.
7c)representoppositeextremes.
Frameworkmodelsemphasizethepatternofbondsofamoleculewhileignoringthesizesoftheatoms.
Space-llingmodelsemphasizethevolumeoccupiedbyindividualatomsatthecostofaclearde-pictionofthebonds;theyaremostusefulincasesinwhichonewishestoexaminetheoverallmolecularshapeandtoassesshowcloselytwononbondedatomsapproacheachother.
Theearliestball-and-stickmodelswereexactlythat:woodenballsinwhichholesweredrilledtoac-commodatedowelsthatconnectedtheatoms.
Plasticversions,includingrelativelyinexpensivestudentsets,becameavailableinthe1960sandprovedtobeavaluablelearningaid.
Preciselyscaledstainlesssteelframeworkandplasticspace-llingmodels,althoughrelativelyexpensive,werestandardequipmentinmostresearchlaboratories.
Computergraphics-basedrepresentationsarerapidlyreplacingclassicalmolecularmodels.
Indeed,theterm"molecularmodeling"asnowusedinor-ganicchemistryimpliescomputergenerationofmod-els.
ThemethanemodelsshowninFigure1.
7werealldrawnonapersonalcomputerusingsoftwarethatpossessesthefeatureofdisplayingandprintingthesamemoleculeinframework,ball-and-stick,andspace-llingformats.
Inadditiontopermittingmod-elstobeconstructedrapidly,eventhesimplestsoft-wareallowsthemodeltobeturnedandviewedfromavarietyofperspectives.
Moresophisticatedprogramsnotonlydrawmolecularmodels,butalsoincorporatecomputa-tionaltoolsthatprovideusefulinsightsintotheelec-trondistribution.
Figure1.
7dillustratesthishigherlevelapproachtomolecularmodelingbyusingcolorstodisplaytheelectricchargedistributionwithintheboundariesdenedbythespace-llingmodel.
Fig-uressuchas1.
7darecalledelectrostaticpotentialmaps.
Theyshowthetransitionfromregionsofhigh-esttolowestelectrondensityaccordingtothecolorsoftherainbow.
Themostelectron-richregionsarered;themostelectron-poorareblue.
Formethane,theoverallshapeoftheelectrostaticpotentialmapissimilartothevolumeoccupiedbythespace-llingmodel.
Themostelectron-richregionsareclosertocarbonandthemostelectron-poorregionsclosertothehydrogenatoms.
(a)(b)(c)(d)FIGURE1.
7(a)Aframework(tube)molecularmodelofmethane(CH4).
Aframeworkmodelshowsthebondsconnectingtheatomsofamolecule,butnottheatomsthemselves.
(b)Aball-and-stick(ball-and-spoke)modelofmethane.
(c)Aspace-llingmodelofmethane.
(d)Anelectrostaticpotentialmapsuperimposedonaball-and-stickmodelofmethane.
Theelectrostaticpotentialmapcorrespondstothespace-llingmodel,butwithanaddedfeature.
Thecolorsidentifyregionsaccordingtotheirelectriccharge,withredbeingthemostnegativeandbluethemostpositive.
—Cont.
FIGURE27.
1Electro-staticpotentialmapsofthe20commonaminoacidslistedinTable27.
1.
Eachaminoacidisorientedsothatitssidechainisintheupperleftcorner.
Thesidechainsaffecttheshapeandpropertiesoftheaminoacids.
27.
2StereochemistryofAminoAcids1053xxxviAGUIDETOUSINGTHISTEXTSPECTROSCOPYSpectroscopycoverageisup-to-dateandthoroughinthisedition.
Chapter13,"Spectroscopy,"featuresNMRspectrathatwerenewlyrecordedonahigh-eldinstrument,andallthetextgureswereproduceddirectlyfromelectronicles.
Inaddition,spectroscopyisintegratedintoallthefunctionalgroupchaptersthatfollow13:Chapters15,16,17,19,20,22,and24,whichcontainspectroscopysectionsandexamplesandproblemsbasedondisplayedspectra.
BIOLOGICALAPPLICATIONSTHROUGHOUTWhilebiologicaltopicsreceivegreatestemphasisinChap-ters25–27,theyarealsointroducedthroughoutthebook,reectingtheirgrowingroleinthestudyoforganicchem-istry.
Examplesinclude:Biologicaloxidationofalcohols(p.
600)Epoxidesinbiologicalprocesses(p.
637)"MethaneandtheBiosphere"(boxedessay,p.
58)Abiologicaldehydrogenation(new,p.
181)Figure19.
5,showingarealisticrepresentationofamicelle(p.
744)"Chiraldrugs"(boxedessay,p.
273)Thisalkylchromatethenundergoesaneliminationreactiontoformthecarbon—oxygendoublebond.
Intheeliminationstep,chromiumisreducedfromCr(VI)toCr(IV).
SincetheeventualproductisCr(III),furtherelectron-transferstepsarealsoinvolved.
15.
11BIOLOGICALOXIDATIONOFALCOHOLSManybiologicalprocessesinvolveoxidationofalcoholstocarbonylcompoundsorthereverseprocess,reductionofcarbonylcompoundstoalcohols.
Ethanol,forexample,ismetabolizedinthelivertoacetaldehyde.
Suchprocessesarecatalyzedbyenzymes;theenzymethatcatalyzestheoxidationofethanoliscalledalcoholdehydrogenase.
Inadditiontoenzymes,biologicaloxidationsrequiresubstancesknownascoen-zymes.
Coenzymesareorganicmoleculesthat,inconcertwithanenzyme,actonasub-stratetobringaboutchemicalchange.
Mostofthesubstancesthatwecallvitaminsarecoenzymes.
Thecoenzymecontainsafunctionalgroupthatiscomplementarytoafunc-tionalgroupofthesubstrate;theenzymecatalyzestheinteractionofthesemutuallycom-plementaryfunctionalgroups.
Ifethanolisoxidized,someothersubstancemustbereduced.
Thisothersubstanceistheoxidizedformofthecoenzymenicotinamideade-ninedinucleotide(NAD).
ChemistsandbiochemistsabbreviatetheoxidizedformofthisCH3CHOAcetaldehydeCH3CH2OHEthanolalcoholdehydrogenaseH3OHCrO3CrOHCHOOOAlkylchromateHHOCOAldehydeorketone600CHAPTERFIFTEENAlcohols,Diols,andThiolsNNNNCNH2ONNH2OPHOHOOOOPOOOOOHOOHFIGURE15.
3StructureofNAD,theoxidizedformofthecoenzymenicotinamideadeninedinucleotide.
13.
10SplittingPatterns:PairsofDoublets5050.
01.
02.
03.
04.
0Chemicalshift(δ,ppm)6.
07.
08.
09.
010.
05.
0CHCH3HWWCl4.
04.
14.
24.
34.
4H3C±C±CH31.
41.
61.
8FIGURE13.
15The200-MHz1HNMRspectrumofiso-propylchloride,showingthedoublet—septetpatternofanisopropylgroup.
13.
9SPLITTINGPATTERNS:THEISOPROPYLGROUPTheNMRspectrumofisopropylchloride(Figure13.
15)illustratestheappearanceofanisopropylgroup.
Thesignalforthesixequivalentmethylprotonsat1.
5ppmissplitintoadoubletbytheprotonoftheH±C±Clunit.
Inturn,theH±C±Clprotonsig-nalat4.
2ppmissplitintoaseptetbythesixmethylprotons.
Adoublet—septetpat-ternischaracteristicofanisopropylgroup.
13.
10SPLITTINGPATTERNS:PAIRSOFDOUBLETSWeoftenseesplittingpatternsinwhichtheintensitiesoftheindividualpeaksdonotmatchthosegiveninTable13.
2,butaredistortedinthatthesignalsforcoupledprotons"lean"towardeachother.
Thisleaningisageneralphenomenon,butismosteasilyillus-tratedforthecaseoftwononequivalentvicinalprotonsasshowninFigure13.
16.
H1±C±C±H2Theappearanceofthesplittingpatternofprotons1and2dependsontheircouplingcon-stantJandthechemicalshiftdifferencebetweenthem.
Whentheratio/Jislarge,twosymmetrical1:1doubletsareobserved.
Werefertothisasthe"AX"case,usingtwoThisprotonsplitsthesignalforthemethylprotonsintoadoublet.
Thesesixprotonssplitthemethinesignalintoaseptet.
HCH3CH3CClAGUIDETOUSINGTHISTEXTxxxviiPROBLEMSOLVING—BYEXAMPLEProblem-solvingstrategiesandskillsareemphasizedthroughout.
Understandingoftopicsiscontinuallyrein-forcedbyproblemsthatappearwithintopicsections.
Formanyproblems,samplesolutionsaregiven.
.
.
.
ANDMOREPROBLEMSEverychapterendswithacomprehensivebankofproblemsthatgivestudentsliberalopportunitytomasterskillsbyworkingproblems.
AndnowmanyoftheproblemsarewrittenexpresslyforusewiththesoftwareontheLearn-ingByModelingCD-ROM.
Bothwithinthechaptersandattheend,theseproblemsareaggedwiththeSpartan-Buildicon.
itsalkoxyoxygengivesanewoxoniumion,whichlosesamoleculeofalcoholinstep5.
Alongwiththealcohol,theprotonatedformofthecarboxylicacidarisesbydissoci-ationofthetetrahedralintermediate.
Itsdeprotonationinstep6completestheprocess.
PROBLEM20.
10Onthebasisofthegeneralmechanismforacid-catalyzedesterhydrolysisshowninFigure20.
4,writeananalogoussequenceofstepsforthespe-ciccaseofethylbenzoatehydrolysis.
Themostimportantspeciesinthemechanismforesterhydrolysisisthetetrahe-dralintermediate.
EvidenceinsupportoftheexistenceofthetetrahedralintermediatewasdevelopedbyProfessorMyronBenderonthebasisofisotopiclabelingexperimentshecarriedoutattheUniversityofChicago.
Benderpreparedethylbenzoate,labeledwiththemass-18isotopeofoxygenatthecarbonyloxygen,thensubjectedittoacid-catalyzedhydrolysisinordinary(unlabeled)water.
Hefoundthatethylbenzoate,recoveredfromthereactionbeforehydrolysiswascomplete,hadlostaportionofitsisotopiclabel.
Thisobservationisconsistentonlywiththereversibleformationofatetrahedralintermediateunderthereactionconditions:ThetwoOHgroupsinthetetrahedralintermediateareequivalent,andsoeitherthelabeledortheunlabeledonecanbelostwhenthetetrahedralintermediaterevertstoethylbenzoate.
Bothareretainedwhenthetetrahedralintermediategoesontoformbenzoicacid.
PROBLEM20.
11Inasimilarexperiment,unlabeled4-butanolidewasallowedtostandinanacidicsolutioninwhichthewaterhadbeenlabeledwith18O.
Whenthelactonewasextractedfromthesolutionafter4days,itwasfoundtocontain18O.
Whichoxygenofthelactonedoyouthinkbecameisotopicallylabeled20.
10ESTERHYDROLYSISINBASE:SAPONIFICATIONUnlikeitsacid-catalyzedcounterpart,esterhydrolysisinaqueousbaseisirreversible.
Thisisbecausecarboxylicacidsareconvertedtotheircorrespondingcarboxylateanionsundertheseconditions,andtheseanionsareincapableofacyltransfertoalcohols.
RCOROXEsterHOHydroxideionROHAlcoholCarboxylateionRCOOXOO4-Butanolide794CHAPTERTWENTYCarboxylicAcidDerivatives:NucleophilicAcylSubstitutionCC6H5OCH2CH3OEthylbenzoate(labeledwith18O)CC6H5OCH2CH3OEthylbenzoateH2OWaterHHHOOHCC6H5OCH2CH3TetrahedralintermediateH2OWater(labeledwith18O)Sinceitisconsumed,hydrox-ideionisareactant,notacatalyst.
maybenamed2-methyl-1,3-epoxyhexane.
Usingtheepoxyprexinthisway,nameeachofthefollowingcompounds:(a)(c)(b)(d)16.
23Thenameoftheparentsix-memberedsulfur-containingheterocycleisthiane.
Itisnum-beredbeginningatsulfur.
Multipleincorporationofsulfurintheringisindicatedbytheprexesdi-,tri-,andsoon.
(a)Howmanymethyl-substitutedthianesarethereWhichonesarechiral(b)Writestructuralformulasfor1,4-dithianeand1,3,5-trithiane.
(c)Whichdithianeisomerisadisulde(d)Drawthetwomoststableconformationsofthesulfoxidederivedfromthiane.
16.
24Themoststableconformationof1,3-dioxan-5-olisthechairformthathasitshydroxylgroupinanaxialorientation.
Suggestareasonableexplanationforthisfact.
Buildingamolecularmodelishelpful.
16.
25OutlinethestepsinthepreparationofeachoftheconstitutionallyisomericethersofmolecularformulaC4H10O,startingwiththeappropriatealcohols.
UsetheWilliamsonethersynthesisasyourkeyreaction.
16.
26Predicttheprincipalorganicproductofeachofthefollowingreactions.
Specifystereo-chemistrywhereappropriate.
(a)(b)(c)CH3CH2CHCH2BrOHNaOHCH3CH2ICONaCH3CH3CH2HBrCH3CH2CHCH3ONaOHOO1,3-Dioxan-5-olOOH3CH3CCH2CH2CH3OOCHCH2CH2CH3OH2C2CH3CH34561648CHAPTERSIXTEENEthers,Epoxides,andSuldesxxxviiiAGUIDETOUSINGTHISTEXTONLINELEARNINGCENTERTheexclusiveCareyOnlineLearningCenter,atwww.
mhhe.
com/carey,isarichresourcethatprovidesadditionalsupportforthefourtheditionofOrganicChem-istry,offeringtutorials,practiceproblems,andassessmentexercisesforeverychapterinthetext.
Thetutorialmaterialsprovideashortoverviewofthechaptercontent,drawingattentiontokeyconcepts.
TheLearningCenteralsoprovidesaccesstoreviewmaterialsfortheseconcepts,usingmultimediaimages,movies,etc.
—includingChimeimages—toenhanceandfacilitatelearning.
Practiceproblemsandassessmentexercisespro-videinstantfeedback,topinpointthetopicsonwhichastu-dentneedstospendmoretime.
THESUMMARYSummariesendingeachchapterarecraftedtoallowstu-dentstochecktheirknowledgeandrevisitchaptercontentinastudy-friendlyformat.
LearningisreinforcedthroughconcisenarrativeandthroughSummaryTablesthatstu-dentsndvaluable.
INSTRUCTIVEBOXEDESSAYSTheessaysinthebookaren'tjustfordecoration;theyhelpstudentsthinkandlearnbyrelatingconceptstobiological,environmental,andotherreal-worldapplications.
Examplesinclude:"MethaneandtheBiosphere""AnEnzyme-CatalyzedNucleophilicSubstitutionofanAlkylHalide""GoodCholesterolBadCholesterolWhat'stheDif-ference"Manyheterocyclicsystemscontaindoublebondsandarerelatedtoarenes.
ThemostimportantrepresentativesofthisclassaredescribedinSections11.
21and11.
22.
3.
16SUMMARYInthischapterweexploredthethree-dimensionalshapesofalkanesandcycloalkanes.
Themostimportantpointtobetakenfromthechapteristhatamoleculeadoptstheshapethatminimizesitstotalstrain.
Thesourcesofstraininalkanesandcycloal-kanesare:1.
Bondlengthdistortion:destabilizationofamoleculethatresultswhenoneormoreofitsbonddistancesaredifferentfromthenormalvalues2.
Anglestrain:destabilizationthatresultsfromdistortionofbondanglesfromtheirnormalvalues3.
Torsionalstrain:destabilizationthatresultsfromtheeclipsingofbondsonadja-centatoms4.
VanderWaalsstrain:destabilizationthatresultswhenatomsorgroupsonnon-adjacentatomsaretooclosetooneanotherThevariousspatialarrangementsavailabletoamoleculebyrotationaboutsinglebondsarecalledconformations,andconformationalanalysisisthestudyofthedif-ferencesinstabilityandpropertiesoftheindividualconformations.
Rotationaroundcar-bon—carbonsinglebondsisnormallyveryfast,occurringhundredsofthousandsoftimespersecondatroomtemperature.
Moleculesarerarelyfrozenintoasingleconformationbutengageinrapidequilibrationamongtheconformationsthatareenergeticallyaccessible.
Section3.
1Themoststableconformationofethaneisthestaggeredconformation.
Itisapproximately12kJ/mol(3kcal/mol)morestablethantheeclipsed,whichistheleaststableconformation.
Staggeredconformationofethane(moststableconformation)Eclipsedconformationofethane(leaststableconformation)Lipoicacid:agrowthfactorrequiredbyavarietyofdifferentorganismsSSCH2CH2CH2CH2COHOXLenthionine:contributestotheodorofShiitakemushroomsSSSSS3.
16Summary1171038CHAPTERTWENTY-SIXLipidsGOODCHOLESTEROLBADCHOLESTEROLWHAT'STHEDIFFERENCECholesterolisbiosynthesizedintheliver,trans-portedthroughoutthebodytobeusedinava-rietyofways,andreturnedtotheliverwhereitservesasthebiosyntheticprecursortoothersteroids.
Butcholesterolisalipidandisn'tsolubleinwater.
Howcanitmovethroughthebloodifitdoesn'tdis-solveinitTheansweristhatitdoesn'tdissolve,butisinsteadcarriedthroughthebloodandtissuesaspartofalipoprotein(lipidproteinlipoprotein).
Theproteinsthatcarrycholesterolfromtheliverarecalledlow-densitylipoproteins,orLDLs;thosethatreturnittotheliverarethehigh-densitylipoproteins,orHDLs.
IftoomuchcholesterolisbeingtransportedbyLDL,ortoolittlebyHDL,theextracholesterolbuildsuponthewallsofthearteriescaus-ingatherosclerosis.
Athoroughphysicalexaminationnowadaysmeasuresnotonlytotalcholesterolcon-centrationbutalsothedistributionbetweenLDLandHDLcholesterol.
AnelevatedlevelofLDLcholesterolisariskfactorforheartdisease.
LDLcholesterolis"bad"cholesterol.
HDLs,ontheotherhand,removeexcesscholesterolandareprotective.
HDLcholesterolis"good"cholesterol.
ThedistributionbetweenLDLandHDLcholes-teroldependsmainlyongeneticfactors,butcanbealtered.
RegularexerciseincreasesHDLandreducesLDLcholesterol,asdoeslimitingtheamountofsatu-ratedfatinthediet.
Muchprogresshasbeenmadeindevelopingnewdrugstolowercholesterol.
Thestatinclass,beginningwithlovastatinin1988fol-lowedbysimvastatinin1991haveprovenespeciallyeffective.
Thestatinslowercholesterolbyinhibitingtheen-zyme3-hydroxy-3-methylglutarylcoenzymeAreduc-tase,whichisrequiredforthebiosynthesisofmeva-lonicacid(seeSection26.
10).
Mevalonicacidisanobligatoryprecursortocholesterol,solessmevalonicacidtranslatesintolesscholesterol.
OHOOOOCH3H3CH3CCH3CH3CH2Simvastatin1INTRODUCTIONAttherootofallscienceisourownunquenchablecuriosityaboutourselvesandourworld.
Wemarvel,asourancestorsdidthousandsofyearsago,whenre-ieslightupasummerevening.
Thecolorsandsmellsofnaturebringsubtlemessagesofinnitevariety.
Blindfolded,weknowwhetherweareinapineforestorneartheseashore.
Wemarvel.
Andwewonder.
HowdoesthereyproducelightWhatarethesubstancesthatcharacterizethefragranceofthepineforestWhathappenswhenthegreenleavesofsummerarereplacedbythered,orange,andgoldoffallTHEORIGINSOFORGANICCHEMISTRYAsoneofthetoolsthatfosteredanincreasedunderstandingofourworld,thescienceofchemistry—thestudyofmatterandthechangesitundergoes—developedslowlyuntilneartheendoftheeighteenthcentury.
Aboutthattime,inconnectionwithhisstudiesofcombustiontheFrenchnoblemanAntoineLaurentLavoisierprovidedthecluesthatshowedhowchemicalcompositionscouldbedeterminedbyidentifyingandmeasuringtheamountsofwater,carbondioxide,andothermaterialsproducedwhenvarioussub-stanceswereburnedinair.
BythetimeofLavoisier'sstudies,twobranchesofchem-istrywerebecomingrecognized.
Onebranchwasconcernedwithmatterobtainedfromnaturalorlivingsourcesandwascalledorganicchemistry.
Theotherbranchdealtwithsubstancesderivedfromnonlivingmatter—mineralsandthelike.
Itwascalledinorganicchemistry.
Combustionanalysissoonestablishedthatthecompoundsderivedfromnat-uralsourcescontainedcarbon,andeventuallyanewdenitionoforganicchemistryemerged:organicchemistryisthestudyofcarboncompounds.
Thisisthedenitionwestillusetoday.
BERZELIUS,WHLER,ANDVITALISMAstheeighteenthcenturygavewaytothenineteenth,JnsJacobBerzeliusemergedasoneoftheleadingscientistsofhisgeneration.
Berzelius,whosetrainingwasinmedi-cine,hadwide-ranginginterestsandmadenumerouscontributionsindiverseareasofchemistry.
Itwashewhoin1807coinedtheterm"organicchemistry"forthestudyofcompoundsderivedfromnaturalsources.
Berzelius,likealmosteveryoneelseatthetime,subscribedtothedoctrineknownasvitalism.
Vitalismheldthatlivingsystemspossesseda"vitalforce"whichwasabsentinnonlivingsystems.
Compoundsderivedfromnaturalsources(organic)werethoughttobefundamentallydifferentfrominorganiccompounds;itwasbelievedinorganiccompoundscouldbesynthesizedinthelaboratory,butorganiccompoundscouldnot—atleastnotfrominorganicmaterials.
In1823,FriedrichWhler,freshfromcompletinghismedicalstudiesinGermany,traveledtoStockholmtostudyunderBerzelius.
AyearlaterWhleracceptedapositionteachingchemistryandconductingresearchinBerlin.
Hewentontohaveadistinguishedcareer,spendingmostofitattheUniversityofGttingen,butisbestrememberedforabriefpaperhepublishedin1828.
Whlernotedthatwhenheevaporatedanaqueoussolutionofammoniumcyanate,heobtained"colorless,clearcrystalsoftenmorethananinchlong,"whichwerenotammoniumcyanatebutwereinsteadurea.
ThetransformationobservedbyWhlerwasoneinwhichaninorganicsalt,ammoniumcyanate,wasconvertedtourea,aknownorganicsubstanceearlierisolatedfromurine.
Thisexperimentisnowrecognizedasascienticmilestone,therststeptowardover-turningthephilosophyofvitalism.
AlthoughWhler'ssynthesisofanorganiccompoundinthelaboratoryfrominorganicstartingmaterialsstruckatthefoundationofvitalistdogma,vitalismwasnotdisplacedovernight.
Whlermadenoextravagantclaimscon-cerningtherelationshipofhisdiscoverytovitalisttheory,butthediewascast,andoverthenextgenerationorganicchemistryoutgrewvitalism.
WhatparticularlyseemedtoexciteWhlerandhismentorBerzeliusaboutthisexperimenthadverylittletodowithvitalism.
Berzeliuswasinterestedincasesinwhichtwoclearlydifferentmaterialshadthesameelementalcomposition,andheinventedthetermisomerismtodeneit.
Thefactthataninorganiccompound(ammoniumcyanate)ofmolecularformulaCH4N2Ocouldbetransformedintoanorganiccompound(urea)ofthesamemolecularformulahadanimportantbearingontheconceptofisomerism.
NH4OCN±Ammoniumcyanate(aninorganiccompound)OC(NH2)2Urea(anorganiccompound)2IntroductionThearticle"WhlerandtheVitalForce"intheMarch1957issueoftheJournalofChemicalEducation(pp.
141–142)describeshowWhler'sexperimentaf-fectedthedoctrineofvital-ism.
AmorerecentaccountofthesignicanceofWh-ler'sworkappearsintheSeptember1996issueofthesamejournal(pp.
883–886).
ThisGermanstampdepictsamolecularmodelofureaandwasissuedin1982tocom-memoratethehundredthan-niversaryofWhler'sdeath.
Thecomputergraphicthatopenedthisintroductorychap-terisalsoamodelofurea.
Lavoisierasportrayedona1943Frenchpostagestamp.
A1979Swedishstamphonor-ingBerzelius.
THESTRUCTURALTHEORYItisfromtheconceptofisomerismthatwecantracetheoriginsofthestructuraltheory—theideathataprecisearrangementofatomsuniquelydenesasubstance.
Ammoniumcyanateandureaaredifferentcompoundsbecausetheyhavedifferentstruc-tures.
Tosomedegreethestructuraltheorywasanideawhosetimehadcome.
Threesci-entistsstandout,however,inbeingcreditedwithindependentlyproposingtheelementsofthestructuraltheory.
ThesescientistsareAugustKekulé,ArchibaldS.
Couper,andAlexanderM.
Butlerov.
ItissomehowttingthatAugustKekulé'searlytrainingattheuniversityinGiessenwasasastudentofarchitecture.
Kekulé'scontributiontochemistryliesinhisdescriptionofthearchitectureofmolecules.
TwothemesrecurthroughoutKekulé'swork:criticalevaluationofexperimentalinformationandagiftforvisualizingmoleculesasparticularassembliesofatoms.
TheessentialfeaturesofKekulé'stheory,developedandpresentedwhilehetaughtatHeidelbergin1858,werethatcarbonnormallyformedfourbondsandhadthecapacitytobondtoothercarbonssoastoformlongchains.
Isomerswerepossiblebecausethesameelementalcomposition(say,theCH4N2Omolec-ularformulacommontobothammoniumcyanateandurea)accommodatesmorethanonepatternofatomsandbonds.
Shortlythereafter,butindependentlyofKekulé,ArchibaldS.
Couper,aScotwork-inginthelaboratoryofCharles-AdolpheWurtzatthecoledeMedicineinParis,andAlexanderButlerov,aRussianchemistattheUniversityofKazan,proposedsimilartheories.
ELECTRONICTHEORIESOFSTRUCTUREANDREACTIVITYInthelatenineteenthandearlytwentiethcenturies,majordiscoveriesaboutthenatureofatomsplacedtheoriesofmolecularstructureandbondingonamoresecurefounda-tion.
Structuralideasprogressedfromsimplyidentifyingatomicconnectionstoattempt-ingtounderstandthebondingforces.
In1916,GilbertN.
LewisoftheUniversityofCal-iforniaatBerkeleydescribedcovalentbondingintermsofsharedelectronpairs.
LinusPaulingattheCaliforniaInstituteofTechnologysubsequentlyelaboratedamoresophis-ticatedbondingschemebasedonLewis'ideasandaconceptcalledresonance,whichheborrowedfromthequantummechanicaltreatmentsoftheoreticalphysics.
Oncechemistsgainedanappreciationofthefundamentalprinciplesofbonding,alogicalnextstepbecametheunderstandingofhowchemicalreactionsoccurred.
MostIntroduction3A1968Germanstampcom-binesadrawingofthestruc-tureofbenzenewithaportraitofKekulé.
TheUniversityofKazanwashometoanumberofpromi-nentnineteenth-centuryor-ganicchemists.
TheircontributionsarerecognizedintwoarticlespublishedintheJanuaryandFebruary1994issuesoftheJournalofChemicalEducation(pp.
39–42and93–98).
LinusPaulingisportrayedonthis1977Voltastamp.
Thechemicalformulasdepictthetworesonanceformsofben-zene,andtheexplosioninthebackgroundsymbolizesPaul-ing'seffortstolimitthetestingofnuclearweapons.
notableamongtheearlyworkersinthisareaweretwoBritishorganicchemists,SirRobertRobinsonandSirChristopherIngold.
Bothheldanumberofteachingpositions,withRobinsonspendingmostofhiscareeratOxfordwhileIngoldwasatUniversityCollege,London.
Robinson,whowasprimarilyinterestedinthechemistryofnaturalproducts,hadakeenmindandapenetratinggraspoftheory.
HewasabletotakethebasicelementsofLewis'structuraltheoriesandapplythemtochemicaltransformationsbysuggestingthatchemicalchangecanbeunderstoodbyfocusingonelectrons.
Ineffect,Robinsonanalyzedorganicreactionsbylookingattheelectronsandunderstoodthatatomsmovedbecausetheywerecarriedalongbythetransferofelectrons.
Ingoldappliedthequanti-tativemethodsofphysicalchemistrytothestudyoforganicreactionssoastobetterunderstandthesequenceofevents,themechanism,bywhichanorganicsubstanceisconvertedtoaproductunderagivensetofconditions.
Ourcurrentunderstandingofelementaryreactionmechanismsisquitegood.
Mostofthefundamentalreactionsoforganicchemistryhavebeenscrutinizedtothedegreethatwehavearelativelyclearpictureoftheintermediatesthatoccurduringthepassageofstartingmaterialstoproducts.
Extensionoftheprinciplesofmechanismtoreactionsthatoccurinlivingsystems,ontheotherhand,isanareainwhichalargenumberofimportantquestionsremaintobeanswered.
THEINFLUENCEOFORGANICCHEMISTRYManyorganiccompoundswereknowntoandusedbyancientcultures.
Almosteveryknownhumansocietyhasmanufacturedandusedbeveragescontainingethylalcoholandhasobservedtheformationofaceticacidwhenwinewastransformedintovinegar.
EarlyChinesecivilizations(2500–3000BC)extensivelyusednaturalmaterialsfortreatingill-nessesandpreparedadrugknownasmahuangfromherbalextracts.
Thisdrugwasastimulantandelevatedbloodpressure.
Wenowknowthatitcontainsephedrine,anorganiccompoundsimilarinstructureandphysiologicalactivitytoadrenaline,ahor-monesecretedbytheadrenalgland.
Almostalldrugsprescribedtodayforthetreatmentofdiseaseareorganiccompounds—somearederivedfromnaturalsources;manyoth-ersaretheproductsofsyntheticorganicchemistry.
Asearlyas2500BCinIndia,indigowasusedtodyeclothadeepblue.
TheearlyPhoeniciansdiscoveredthatapurpledyeofgreatvalue,Tyrianpurple,couldbeextractedfromaMediterraneanseasnail.
Thebeautyofthecoloranditsscarcitymadepurplethecolorofroyalty.
Theavailabilityofdyestuffsunderwentanabruptchangein1856whenWilliamHenryPerkin,an18-year-oldstudent,accidentallydiscoveredasimplewaytoprepareadeep-purpledye,whichhecalledmauveine,fromextractsofcoaltar.
Thisledtoasearchforothersyntheticdyesandforgedapermanentlinkbetweenindustryandchemicalresearch.
Thesyntheticberindustryasweknowitbeganin1928whenE.
I.
DuPontdeNemours&CompanyluredProfessorWallaceH.
CarothersfromHarvardUniversitytodirecttheirresearchdepartment.
InafewyearsCarothersandhisassociateshadpro-ducednylon,therstsyntheticber,andneoprene,arubbersubstitute.
Syntheticbersandelastomersarebothproductsofimportantcontemporaryindustries,withaneconomicinuencefarbeyondanythingimaginableinthemiddle1920s.
COMPUTERSANDORGANICCHEMISTRYAfamiliararrangementofthesciencesplaceschemistrybetweenphysics,whichishighlymathematical,andbiology,whichishighlydescriptive.
Amongchemistry'ssubdisci-4IntroductionThediscovererofpenicillin,SirAlexanderFleming,hasap-pearedontwostamps.
This1981Hungarianissuein-cludesbothalikenessofFlem-ingandastructuralformulaforpenicillin.
Manycountrieshavecele-bratedtheirchemicalindustryonpostagestamps.
Thestampshownwasissuedin1971byArgentina.
plines,organicchemistryislessmathematicalthandescriptiveinthatitemphasizesthequalitativeaspectsofmolecularstructure,reactions,andsynthesis.
Theearliestapplica-tionsofcomputerstochemistrytookadvantageofthe"numbercrunching"powerofmainframestoanalyzedataandtoperformcalculationsconcernedwiththemorequan-titativeaspectsofbondingtheory.
Morerecently,organicchemistshavefoundthegraph-icscapabilitiesofminicomputers,workstations,andpersonalcomputerstobewellsuitedtovisualizingamoleculeasathree-dimensionalobjectandassessingitsabilitytointer-actwithanothermolecule.
Givenabiomoleculeofknownstructure,aprotein,forexam-ple,andadrugthatactsonit,molecular-modelingsoftwarecanevaluatethevariouswaysinwhichthetwomayttogether.
Suchstudiescanprovideinformationonthemechanismofdrugactionandguidethedevelopmentofnewdrugsofgreaterefcacy.
Theinuenceofcomputersonthepracticeoforganicchemistryisasignicantrecentdevelopmentandwillberevisitednumeroustimesinthechaptersthatfollow.
CHALLENGESANDOPPORTUNITIESAmajorcontributortothegrowthoforganicchemistryduringthiscenturyhasbeentheaccessibilityofcheapstartingmaterials.
Petroleumandnaturalgasprovidethebuildingblocksfortheconstructionoflargermolecules.
Frompetrochemicalscomesadazzlingarrayofmaterialsthatenrichourlives:manydrugs,plastics,syntheticbers,lms,andelastomersaremadefromtheorganicchemicalsobtainedfrompetroleum.
Asweenteranageofinadequateandshrinkingsupplies,theusetowhichweputpetroleumloomslargeindeterminingthekindofsocietywewillhave.
Alternativesourcesofenergy,especiallyfortransportation,willallowagreaterfractionofthelimitedpetroleumavail-abletobeconvertedtopetrochemicalsinsteadofbeingburnedinautomobileengines.
Atamorefundamentallevel,scientistsinthechemicalindustryaretryingtodevisewaystousecarbondioxideasacarbonsourceintheproductionofbuildingblockmolecules.
Manyofthemostimportantprocessesinthechemicalindustryarecarriedoutinthepresenceofcatalysts.
Catalystsincreasetherateofaparticularchemicalreactionbutarenotconsumedduringit.
Insearchingfornewcatalysts,wecanlearnagreatdealfrombiochemistry,thestudyofthechemicalreactionsthattakeplaceinlivingorgan-isms.
Allthesefundamentalreactionsarecatalyzedbyenzymes.
Rateenhancementsofseveralmillionfoldarecommonwhenonecomparesanenzyme-catalyzedreactionwiththesamereactionperformedinitsabsence.
Manydiseasesaretheresultofspecicenzymedecienciesthatinterferewithnormalmetabolism.
Inthenalanalysis,effec-tivetreatmentofdiseasesrequiresanunderstandingofbiologicalprocessesatthemolec-ularlevel—whatthesubstrateis,whattheproductis,andthemechanismbywhichsub-strateistransformedtoproduct.
Enormousadvanceshavebeenmadeinunderstandingbiologicalprocesses.
Becauseofthecomplexityoflivingsystems,however,wehaveonlyscratchedthesurfaceofthisfascinatingeldofstudy.
Spectacularstrideshavebeenmadeingeneticsduringthepastfewyears.
Althoughgenerallyconsideredabranchofbiology,geneticsisincreasinglybeingstudiedatthemolecularlevelbyscientiststrainedaschemists.
Gene-splicingtechniquesandmethodsfordeterminingtheprecisemolecularstructureofDNAarejusttwoofthetoolsdrivingthenextscienticrevolution.
Youarestudyingorganicchemistryatatimeofitsgreatestinuenceonourdailylives,atatimewhenitcanbeconsideredamaturescience,whenthechallengingques-tionstowhichthisknowledgecanbeappliedhaveneverbeenmoreimportant.
Introduction5ADNAdoublehelixaspic-turedona1964postagestampissuedbyIsrael.
6IntroductionWHEREDIDTHECARBONCOMEFROMAccordingtothe"big-bang"theory,theuni-versebeganexpandingabout12bil-lionyearsagowhenanincrediblydense(1096gиcm3),incrediblyhot(1032K)ballcontainingallthematterintheuniverseexploded.
Noparticlesmoremassivethanprotonsorneutronsexisteduntilabout100safterthebigbang.
Bythen,thetemper-aturehaddroppedtoabout109K,lowenoughtopermittheprotonsandneutronstocombinetoformheliumnuclei.
Conditionsfavorablefortheformationofhe-liumnucleilastedforonlyafewhours,andtheuni-versecontinuedtoexpandwithoutmuch"chem-istry"takingplaceforapproximatelyamillionyears.
Astheuniverseexpanded,itcooled,andthepositivelychargedprotonsandheliumnucleicom-binedwithelectronstogivehydrogenandheliumatoms.
Together,hydrogenandheliumaccountfor99%ofthemassoftheuniverseand99.
9%ofitsatoms.
Hydrogenisthemostabundantelement;88.
6%oftheatomsintheuniversearehydrogen,and11.
3%arehelium.
Someregionsofspacehavehigherconcentra-tionsofmatterthanothers,highenoughsothattheexpansionandcoolingthatfollowedthebigbangislocallyreversed.
Gravitationalattractioncausesthe"matterclouds"tocollapseandtheirtemperaturetoincrease.
Afterthebigbang,thenuclearfusionofhy-drogentoheliumtookplacewhenthetemperaturedroppedto109K.
Thesamenuclearfusionbeginswhengravitationalattractionheatsmattercloudsto107Kandtheballofgasbecomesastar.
Thestarex-pands,reachingamoreorlesssteadystateatwhichhydrogenisconsumedandheatisevolved.
Thesizeofthestarremainsrelativelyconstant,butitscorebecomesenrichedinhelium.
Afterabout10%ofthehydrogenisconsumed,theamountofheatproducedisinsufcienttomaintainthestar'ssize,anditbeginstocontract.
Asthestarcontractsthetemperatureofthehelium-richcoreincreases,andheliumnucleifusetoformcarbon.
22nTwoneutronsTwoprotonsHeliumnucleusnn3ThreeheliumnucleiNucleusof12Cnn66nFusionofanucleusof12Cwithoneofheliumgives16O.
Eventuallythehelium,too,becomesde-pleted,andgravitationalattractioncausesthecoretocontractanditstemperaturetoincreasetothepointatwhichvariousfusionreactionsgiveyetheav-iernuclei.
Sometimesastarexplodesinasupernova,cast-ingdebrisintointerstellarspace.
Thisdebrisincludestheelementsformedduringthelifeofthestar,andtheseelementsndtheirwayintonewstarsformedwhenacloudofmattercollapsesinonitself.
Ourownsunisbelievedtobea"secondgeneration"star,oneformednotonlyfromhydrogenandhelium,butcontainingtheelementsformedinearlierstarsaswell.
Accordingtoonetheory,earthandtheotherplanetswereformedalmost5billionyearsagofromthegas(thesolarnebula)thattrailedbehindthesunasitrotated.
Beingremotefromthesun'score,thematterinthenebulawascoolerthanthatinthein-teriorandcontracted,accumulatingheavierele-mentsandbecomingtheseriesofplanetsthatnowcirclethesun.
Oxygenisthemostabundantelementonearth.
Theearth'scrustisrichincarbonateandsili-caterocks,theoceansarealmostentirelywater,andoxygenconstitutesalmostonefthoftheairwebreathe.
Carbonranksonlyfourteenthamongtheel-ementsinnaturalabundance,butissecondtooxy-geninitsabundanceinthehumanbody.
Itisthechemicalpropertiesofcarbonthatmakeituniquelysuitableastherawmaterialforthebuildingblocksoflife.
Let'sndoutmoreaboutthosechemicalproperties.