大一下-有机化学化学ch8ether

Organic

ChemistryApril

22,

2015for

Students

of

Medicine

and

Biology大学化学III和大学化学III（2）EthersR-O-R’C2H5-O-C2H5Diethyl

etherDiethyl

EtherCheck

the

“fine

print”8.1.1

Structure,

classificationand

nomenclatureCOC110。醚键1.18Dgeneral

formula:

R-O-R’symmetrical

ether

单mixedethercyclicether混环四氢酚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环醚环氧化合物

(epoxide)大环多醚(4)

Cyclic

ether1OH3CCH2CHCH33CHCH2CH3O12CH232,

3-Dimethyl

oxirane2-Ethyl

oxirane大环多醚(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.比同数碳原子的醇低得多。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、碱性和弱酸性条件下稳定，常用作溶剂C上连有氧，H易被氧化碳有亲电性，但难亲核取代碳有亲电性，可亲核取代较好的离去基氧有碱性，可与酸结合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不易断裂C

O

CH形成氧正离子后吸电子能力增强

C－O键更易断裂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机制断裂，叔烷基醚按SN1机制断裂，芳基烷基醚总是烷氧键断裂。CH3

O

CH3HICH3OH

+

CH3I

HI

CH3I机理(SN2)：CH3

O

CH3+

H+CH3

O

CH3HCH3

O

CH3H+

I－CH3OH

+

CH3ICH3

O

C(CH3)3HICH3OH

+

(CH3)3CI机理(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检验：过氧化物＋FeSO4Fe2(SO4)3K3Fe(SCN)6红色除去：在蒸馏前，加入5％FeSO4溶液EPOXIDESCCOC

CRCO3H中文书：P778.2OHHOOOOHOOHTriptolide雷公藤内酯醇免疫抑制剂7R,8S)-DisparlureGypsy

moth

pheromone雌舞毒蛾引诱剂OCC1,

2－环氧化合物Epoxides

Oxiranes（IUPAC）Epoxides---Reaction

of

Opening

RingOH2C

CH2OC

C110。<110。1.18D1.18D张力环能溶于水、乙醇、乙醚发生亲核取代，重要有机H2COCH2＋

Nu－HOCH2CH2NuH+H2COCH2H2O/H+ROH/H+

HX

HCNBH3NH3RMgXLiAlH4HOCH2CH2OHROCH2CH2OHXCH2CH2OH(CH3CH2O)3BNH2CH2CH2OHRCH2CH2OHCH3CH2OHRMgX

+CH2

CH2ORCH2CH2OHCH3ONa

+CH2

CH2OCH3OCH2CH2OH1.

Acid

catalyst:

亲核试剂进攻取代较多的环氧烷碳原子(SN1)(1)CH3CHCH2Nu－(2)OHOCH3CHCH2H+CH3CHHOCH2Nu2.Base

catalyst：亲核试剂进攻取代较少的环氧烷碳原子(SN2)(1)CH3CHO(2)CH2Nu–Nu－CH3CH

CH2O(1)位阻较大＋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

冠醚的络合反应和相转移催化腔体直径0.35012-C-415－C－518－C－621－C－7金属离子直径NaLiK铵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.冠醚与金属离子所形成的络合物可溶于低极性的着负离子一起进入，并且随带中。OOOOOOK4MnO

－溶于苯中。紫色苯Phase-transfer

catalyst相转移催化剂能使互不相溶的两相中的物质发生反应或加速反应的催化剂。CH3COOHKMnO4,

Benzene二环己基－18－冠－6100%界面传递CN－传递Cl－水相有机相OOOOOOKOOOOOOKCN－Cl－KCl

＋K＋CN－

＋OOOOOOKCN－RCl

＋OOOOOKOCl–RCN

＋RX

+

KCNPTCRCN

+

KX8.4

Preparationof

ether(醚的

)1.醇的分子间脱水—简单醚的2ROHH2SO4

ROR

+

H

O2HOCH2CH2CH2CH2OH

H2SO4O2.Willianmson

法—混合醚的RONaArONaROR'ArOR'+

R'X不能用叔卤代烷，以减少消除；芳基烷基醚的

总是用酚钠。例1：

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

C不能用C2H5ONa和(CH3)3CBr,因为此时以消除反应为主。CH3CH3BrC2H5ONaCH3

CCH3C