英语大一下8单元课件

Chapter8

Alcohols,Phenols,andEthers

YulingWang

Alocoholhasahydroxylgroup(-OH)bondtocarbonatom;

Phenolhasahydroxylgroupbondedtoanaromaticring;

Etherhasanoxygenatombondedtotwoorganicgroups.8.1NamingAlcohols,Phenols,andEtherAlcoholsprimary(1°)secondary(2°)tertiary

(3°)STEP1.

Selectthelongestcarbonchaincontainingthe

hydroxylgroup,andreplacetheending-e

with-ol.STEP2.

Number

theparentchainbeginningattheend

nearerthehydroxylgroup.STEP3.

Writethenamelistingthesubstituents

in

alphabetical

order.123412342-Methyl-2-Pentanolcis-1,4-Cyclohexanediol3-Phenyl-2-butanolSomewell-knownalcoholsalsohavecommonnames:Benzylalcohol

(Phenylmethanol)

tert-Butylalcohol(2-Methyl-2-propanol)

Glycerol(1,2,3-Propanetriol),(2S)(3E)-1-氯-3-戊烯-2-醇COHCH2CLHCHCH3H13425SE(2S)(3E)-1-chloro-3-pentene-2-olPhenols:Phenolsarenamedassubstitutedaromaticcompoundswith

-phenol

astheparentname.m-Methylphenol(m-Cresol)2,4-DinitrophenolEthers:

Simpleethersarenamedbyidentifyingthetwoorganicgroupsandaddingthewordether.tert-ButylmethyletherEthylphenyletherIfmorethanoneetherlinkageispresent,orother

functionalgroupsarepresent,theetherpartisnamedasanalkoxy

substituentontheparentcompound.4-tert-Butoxycyclohexenep-Dimethoxybenzene

Problem8.1GiveIUPACnamesforthefollowingcompounds:5-Methyl-2,4-hexanediol2-Methyl-4-phenyl-2-butanol4,4-Dimethylcyclohexanolcis-2-Bromocyclopentanol

Problem8.2IdentifythealcoholsinProblem8.1asprimary,secondary,ortertiary.SecondaryTertiarySecondarySecondaryProblem8.3.DrawstructurescorrespondingtothefollowingIUPACnames:(a)2-Methyl-2-hexanol(b)1,5-Hexanediol(c)2-Ethyl-2-buten-1-ol(d)3-Cyclohexen-1-ol(e)o-Bromophenol(f)2,4,6-Trinitrophenol

Problem8.4.NamethefollowingethersbyIUPACrules:DiisopropyletherCyclopentyl

propylether1-Bromo-4-methoxybenzeneEthylisobutylether8.2PropertiesofAlcohols,Phenols,andEthers:HydrogenBonding

sp3-hybridizedAlcoholsandphenolsdiffersignificantlyfromthehydrocarbonsandalkylhalides,

alcoholshavehigherboilingpointsofsimilarmolecularweight.Alcoholsandphenolshavehighboilingpointsbecause,likewater,theyformhydrogenbondsintheliquidstate.hydrogenbonds

Ethers,becausetheylackhydroxylgroups,can'tformhydrogenbondsandthereforehavelowerboilingpoints.

8.3PropertiesofAlcoholsandPhenols:AcidityAlcoholsandphenolsarebothweaklybasic

and

weaklyacidic.AsweakLewisbasesarereversiblyprotonatedbystrongacidstoyieldoxoniumions,ROH2+.As

weakacids

dissociate

indiluteaqueoussolutionbydonatingaprotontowatergeneratingH3O+andan

alkoxideion(RO-)oraphenoxideion(ArO-).Alcoholsareas

acidicaswatercan

reactwithalkalimetals

toyieldmetalalkoxidesthatarestrongbases.Potassiumtert-butoxideMethanolSodiummethoxidetert-Butylalcohol

Phenolsareaboutamilliontimesmoreacidicthanalcohols.Sodiutn

phenoxidePhenol8.4SynthesisofAlcohols

Alcoholscanbepreparedbyhydrationofalkenes.1-Methylcyclohexene1-MethylcyclohexanolAlcoholsispreparedby

reductionofcarbonylcompounds.ReductionofAldehydesandKetonesReducing

reagents:

sodium

borohydride,NaBH4

andLithiumaluminumhydride,LiAlH4(morepowerful).ReductionofEstersandCarboxylicAcidsMethyl2-pentenoateProblem8.5.Howwouldyoucarryoutthefollowingreactions?LithiumaluminumhydridesodiumborohydrideProblem8.6WhatcarbonylcompoundsgivethefollowingalcoholsonreductionwithLiAlH4?Showallpossibilities.

8.5ReactionsofAlcohols1-Methylcyclohexanol

1-Methylcyclohexene(91%)DehydrationofAlcohols

Alcohols

istreatmentwithastrongacidundergo

dehydration-theeliminationofH2O-togivealkenes.Acid-catalyzeddehydrationsusuallyfollowZaitsev'srule

andyieldthemorehighlysubstitutedalkeneasmajorproduct.(major)(minor)Mechanism:

E1

Problem8.7Predicttheproductsyouwouldexpectfromthefollowingreactions.Indicatethemajorproductineachcase.

Problem8.8.Whatalcoholsmightthefollowingalkeneshavebeenmadefrom?2.OxidationofAlcoholsPrimaryalcoholSecondaryalcoholTertaryalcohol

Primaryalcoholoxidizedtoaldehyde

is

use

of

Pyridinium

chlorochromate(PCC,C5H6NCrO3Cl)

indichloromethane.1-HeptanolHeptanal(78%)

Primaryalcoholoxidizedtocarboxylicacidisuse

of

chromium

trioxide(CrO3)

and

sodiumdichromate

(Na2Cr2O7)inaqueousacid

solution,.1-DecanolDecanoicacid(83%)4-tert-Butylcyclohexanol4-tert-ButylcyclohexanoneProblem8.9Whatalcoholswouldgivethefollowing

productsonoxidation?Problem8.10.WhatproductswouldyouexpecttoobtainfromoxidationofthefollowingalcoholswithCrO3?

(a)Cyclohexanol(b)1-Hexanol(c)2-HexanolProblem8.11.WhatproductswouldyouexpecttoobtainfromoxidationofthealcoholsinProblem8.10withpyridinium

chlorochromate(PCC)?3.Conversion

intoEthersAlcoholsareconvertedintoethersbyalkoxide

ion

react

withanalkylhalide----Williamson

etherSynthesis.CyclopentoxideionCyclopentylmethylether(74%).SN2reactions,primaryalkylhalidesworkbestbecausecompetitiveE2eliminationcanoccurwithmorehindered

substrates.Unsymmetricalethersarepreparedbyreactionofthemorehinderedalkoxidepartnerwiththelesshinderedalkylhalidepartner,ratherthanviceversa.

Problem8.12Treatmentofcyclohexanolwithsodiummetalgivesanalkoxideionthatundergoesreactionwithiodoethanetoyieldcyclohexylethylether.Writethereaction,showingallthesteps.

Problem8.13Howwouldyoupreparethefollowingethers?

8.6synthesisandReactionsofPhenolsSynthesisofPhenolsToluenep-Toluenesulfonicacidp-Methylphenol

Alcohol-LikeReactionsofPhenols(Williamsonethersynthesis)2.ElectrophilicAromaticSubstitution

ReactionsofPhenols

The-OHgroupisanactivating,ortho-andpara-directing

substituentinelectrophilicaromaticsubstitutionreactions.Treatmentofaphenolwithastrongoxidizingagentsuchassodiumdichromateyieldsacyclohexadienedione,orquinone:BenzoquinonePhenol3.OxidationofPhenols:quinones

8.7SynthesisandReactionsofEthersSynthesisofEthersAnalkoxideionAnetherAnalcoholReactionsofEthersEthersundergoonlyonegeneralreaction--theyarecleavedbystrongacidssuchasaqueousHIorHBr.EtherswithonlyprimaryandsecondaryalkylgroupsreactbyanSN2pathwayinwhichnucleophilichalideionattackstheprotonatedetheratthelesshighlysubstitutedsite.EtherswithatertiaryalkylgroupcleavebyanSN1mechanismbecausetheycanproducestableintermediatecarbocations.Problem8.17.WhatproductsdoyouexpectfromthereactionofthefollowingetherswithHI?

SummaryandKeyWordsAlcohols,phenols,andethersareorganicderivativesofwaterinwhichoneorbothofthewaterhydrogenshavebeenreplacedbyorganicgroups.Alcoholsarecompoundsthathavean-OHbondedtoanalkylgroup.Theycanbepreparedinmanyways,includinghydrationofalkenes.Themostgeneralmethodofalcoholsynthesisinvolvesreductionofacarbonylcompound.Aldehydes,esters,andcarboxylicacidsyieldprimaryalcoholsonreduction;ketonesyieldsecondaryalcohols.Alcoholsareweakacidsandcanbeconvertedintotheiralkoxideanionsontreatmentwithastrongbaseorwithanalkalimetal.Alc