大一下-有機化學化學ch8ether

Organic

ChemistryApril

22,

2015for

Students

of

Medicine

and

Biology大學化學III和大學化學III（2）EthersR-O-R’C2H5-O-C2H5Diethyl

etherDiethyl

EtherCheck

the

“fine

print”8.1.1

Structure,

classificationand

nomenclatureCOC110。醚鍵1.18Dgeneral

formula:

R-O-R’symmetrical

ether

單mixedethercyclicether混環(huán)四氫酚Marijuana（）Nomenclature1.Names

of

alkyl

(or

aryl

)

+

ether(1)

symmetrical

etherCH3-O-CH3dimethyl

ethermethyl

etherOphenyl

ether(2)

Mixed

ether:

AlphabeticallyOEthyl

methyl

etherOEthyl

isopropyl

etherO-CH3methyl

phenyl

etherOCH2CH3Cyclopentyl

ethyl

ether(3)

Complicated

ether:-OR

alkoxyOCH2CH33-ethoxy-4-methyloctaneOCH3OH2-methoxyphenol環(huán)醚環(huán)氧化合物

(epoxide)大環(huán)多醚(4)

Cyclic

ether1OH3CCH2CHCH33CHCH2CH3O12CH232,

3-Dimethyl

oxirane2-Ethyl

oxirane大環(huán)多醚(OCH2CH2)n冠醚（Crown

ether）OOO

OO

O18-冠-6(18-Crown-6)OOO

OO

O二苯并-18-冠-618Crown6OOOOO

O18-Crown-6X-K+8.1.2

Physical

propertyb.p.比同數碳原子的醇低得多。CH3OCH3b.p.

－24.9C2H5OC2H534.6C2H5OHb.p.

78.4CH3CH2CH2CH2OH

Chemical

propertyChemical

property

is

stable，often

assolvent.C－O－C

bond

could

be

brokenunder

extreme

condition.醚在中性、堿性和弱酸性條件下穩(wěn)定，常用作溶劑C上連有氧，H易被氧化碳有親電性，但難親核取代碳有親電性，可親核取代較好的離去基氧有堿性，可與酸結合O

RR'

CHH+HHR'

C

OR1.

Reactionwithcold

concentratedacids(formationofoxonium

salt)：Cl-CH3CH2OCH2CH3+HClHCH3CH2OCH2CH3+protonated

ether

,unstable+2H

OCl-HCH3CH2OCH

2CH

3CH3CH2OCH

2CHH

O3+3

+

+Cl-+C

O

C不易斷裂C

O

CH形成氧正離子后吸電子能力增強

C－O鍵更易斷裂R

O

R'

+

HXROH

+

R'XReaction

activity：HI>HBr>HCl2.

Cleavage

of

ethers

by

hot

acids(HI,

HBr,

HCl)伯烷基醚按SN2機制斷裂，叔烷基醚按SN1機制斷裂，芳基烷基醚總是烷氧鍵斷裂。CH3

O

CH3HICH3OH

+

CH3I

HI

CH3I機理(SN2)：CH3

O

CH3+

H+CH3

O

CH3HCH3

O

CH3H+

I－CH3OH

+

CH3ICH3

O

C(CH3)3HICH3OH

+

(CH3)3CI機理(SN1):CH3

O

C(CH3)3

HI

H+

CH3 O

C(CH3)3H(CH3)3C

+

CH3OHI－3

3（CH

)

CI3CH

IOCH3

57%HI

120--130

COH

+

CH3I3.

Formation

of

peroxide.hydrogenof

α-carbonCH3CH2O2O

CHCH3

CH3CH2HO

CHCH3OOH檢驗：過氧化物＋FeSO4Fe2(SO4)3K3Fe(SCN)6紅色除去：在蒸餾前，加入5％FeSO4溶液EPOXIDESCCOC

CRCO3H中文書：P778.2OHHOOOOHOOHTriptolide雷公藤內酯醇免疫抑制劑7R,8S)-DisparlureGypsy

moth

pheromone雌舞毒蛾引誘劑OCC1,

2－環(huán)氧化合物Epoxides

Oxiranes（IUPAC）Epoxides---Reaction

of

Opening

RingOH2C

CH2OC

C110。<110。1.18D1.18D張力環(huán)能溶于水、乙醇、乙醚發(fā)生親核取代，重要有機H2COCH2＋

Nu－HOCH2CH2NuH+H2COCH2H2O/H+ROH/H+

HX

HCNBH3NH3RMgXLiAlH4HOCH2CH2OHROCH2CH2OHXCH2CH2OH(CH3CH2O)3BNH2CH2CH2OHRCH2CH2OHCH3CH2OHRMgX

+CH2

CH2ORCH2CH2OHCH3ONa

+CH2

CH2OCH3OCH2CH2OH1.

Acid

catalyst:

親核試劑進攻取代較多的環(huán)氧烷碳原子(SN1)(1)CH3CHCH2Nu－(2)OHOCH3CHCH2H+CH3CHHOCH2Nu2.Base

catalyst：親核試劑進攻取代較少的環(huán)氧烷碳原子(SN2)(1)CH3CHO(2)CH2Nu–Nu－CH3CH

CH2O(1)位阻較大＋Nu－CH3CH

CH2O（2）CH3CHNuCH2OHH2ONu－:RO－、PhO－、RMgXC

COHHCH3CH3CH3ONa

+?Unsymmetrical

EpoxideCH3OHC

COHHHCCH333CH

ONa

+BasicLeast

Hindered3CH

OHC

COHHCH3CH3+ACIDIC

CONDITIONS?H+CH3OHC

COHHCH3CH3H+C

CHOHHCH3CH3CCOHHHCH3CH3CCOHHHCH3OCH3CH3Most

Substituted8.3

冠醚的絡合反應和相轉移催化腔體直徑0.35012-C-415－C－518－C－621－C－7金屬離子直徑NaLiK銨OOOOOCrown

etherO18-Crown-6Phase-transfer

agentThe

crown–g

omplexis

called

an

inclusioncompound.The

ability

of

a

host

to

bind

only

certain

guests

isan

example

of

molecular

recognition.Molecular

recognition

explains

how

enzymesrecognize

their

substrates,

how

antibodies

recognize ,

howdrugs

recognize

receptors,

and

many

other

biochemical

processes.冠醚與金屬離子所形成的絡合物可溶于低極性的著負離子一起進入，并且隨帶中。OOOOOOK4MnO

－溶于苯中。紫色苯Phase-transfer

catalyst相轉移催化劑能使互不相溶的兩相中的物質發(fā)生反應或加速反應的催化劑。CH3COOHKMnO4,

Benzene二環(huán)己基－18－冠－6100%界面?zhèn)鬟fCN－傳遞Cl－水相有機相OOOOOOKOOOOOOKCN－Cl－KCl

＋K＋CN－

＋OOOOOOKCN－RCl

＋OOOOOKOCl–RCN

＋RX

+

KCNPTCRCN

+

KX8.4

Preparationof

ether(醚的

)1.醇的分子間脫水—簡單醚的2ROHH2SO4

ROR

+

H

O2HOCH2CH2CH2CH2OH

H2SO4O2.Willianmson

法—混合醚的RONaArONaROR'ArOR'+

R'X不能用叔鹵代烷，以減少消除；芳基烷基醚的

總是用酚鈉。例1：

CH3CH2OC(CH3)3解：(CH3)3CONa+CH3CH2BrC2H5OC(CH3)3CH3

C不能用C2H5ONa和(CH3)3CBr,因為此時以消除反應為主。CH3CH3BrC2H5ONaCH3

CCH3C