8

2010-03

8 (Aromatic Compounds)

2010-03

Many compouds isolated from nature sources

are aromatic in part. In addition to benzene,benzalhyde and toluene,such compouds as the steroidal hormone estrone and well-known analgesic morphine have aromatic rings.

estronemorphinebenzenebenzalhydetoluene,

8 1 2 3

8.1 1 1825Meacheal Faraday, CH;1834: E. Mitscherlich , CFGerhardt,78C6H6

1825(Michael Faraday,1791 1867)19

1834(EEMitscherlich,1794 1863),

(CFGerhardt,1815 1856)78C6H6

2 kekule1865 a: :C6H6 b: c:

Kekule

Kekule snake dream

---------------------------------------------

189025

Kekule d:

e:f:

kJ / mol 119.5 231.8 119.53=358.5 208.5 () () () ()

C=C 119.5 115.9 119.5 69.5kJ / mol 358.5 - 208.5 = 150 kJ / mol 231.8 - 208.5 = 23.3 kJ / mol

g:

3

Each sp2 hybridized C in the ring has an unhybridized p orbital perpendicular to the ring which overlaps around the ring.

Each sp2 hybridized C in the ring has an unhybridized p orbital perpendicular to the ring which overlaps around the ring.

4

8.2 Benzen phenyl benzyl phenyl methyl)

(Aryl) (Ph)C6H5-1

2 ortho-meta-para-

12-13-14-

2--5- 3--5-

3 1 C7H7Cl

2 C8H9Br

4

8.3

One of the most important reactions of arenes is electrophilic aromatic substitution, in which an electrophile reacts with the ring, forming a new bond to a ring carbon with the loss of one hydrogen. In general, these reactions require a Lewis acid catalyst, as shown below for the reaction of bromine with benzene, catalyzed by FeBr3. The role of the FeBr3 is to complex the bromine to form a bromonium cation-like species (which is often simply referred to as Br+) which is the actual electrophilic agent.

1

a:

b:XeF2 , XeF4 , XeF6Cl2+FeCl3 , HOClBr2 , Br2 + Fe , Br2 + I , HOBr , CH3COOBrICl , I2 + HNO3 , I2 + HgO, KI

c:Cl22Cl + Cl + HCl+ Cl2+ Cl h*

d:+ Cl2FeCl3+58% (bp159oC)42% (bp162oC)+ Br2FeBr3130-140oC+ HBr75%

Cl2 hCl2 hCl2 h-H2O-H2OH2OH2OH2O

2 + HNO3 +H2SO450-60oC, 98%+ H2O HNO3 + 2H2SO4 H3O+ + +NO2 + 2 HSO4-+ +NO2NO2+ HSO4-+ H2SO4NO2

3

4 Friedel-Crafts reaction.

(1)Friedel-Crafts acylation reaction

2Friedel-Crafts alkylation reaction.

5 , .6 : .

1

1 :

2 :

3 A or B or C

8.41

2 (1) ;(2);(3).3 :().

4

> 60%G

>40% G

(1) (2)

: .

,,:5

: .,. .

(1)(8).,.1

EABCDB CDA

2 456

3

6 1A B

2

123

123

123

8.5 1 2 1 V2O5+ O2V2O5 400-500oC

2 KMnO4 K2Cr2O7-H2SO4

3 CrO3 +Ac2O CrO3 +Ac2OH2O4 MnO2MnO2H2SO4

MnO2 H2SO4

* CrO3 +Ac2O K2Cr2O7-H2SO4, KMnO4-H2O, KMnO4-H2SO4-H2O HNO3 V2O5

3 1 2 3 H2/C6H6Cl63Cl23H2 Pt h+

3 Birch

1 2Li Na 3 14- 25-

4 C=C5 14-

Na + NH3Na+ + e-) NH3CH3OH -CH3O-(e-) NH3CH3OH

8.6 12-1

CH2Cl2 C6H5CH2C6H5

C6H6 + ClCH2CH2Cl C6H5CH2CH2C6H5

CHCl3 (C6H5)3CH

CCl4 (C6H5)3CClAlCl3 - 2

(C6H5)3CH (C6H5)3COH

(C6H5)3CH (C6H5)3CBr

(C6H5)3CH + Na+NH2 (C6H5)3C-Na+ + NH3 H2CrO4 HOAc3 * * Br2 CH3CH3 C6H5CH3 NH3 (C6H5)3CH (C6H5)3CH CH=CH

pka ~50 41 34-35 34 31.5 25

Ph3C Gomberg 19002Ph3CClPh3C-O-O-CPh3Ph3C-CPh3Zn or AgZn O2mp:185oC C 88% H 6% 94%2Ph3CClZn CO2Ph3C

Ph3C-O-O-CPh31M2% 0.01M10% 100%.1968

22- 24-1

2 1* 2C6H6 C6H5-C6H5 + H2 2*3*4*3

2 1,4,5,82,3,6,71,4,5,82,3,6,79,101-82-73-64-59-10910 1

sp21 O3 2 1 O3 2

13

2

+ Cl21,4- 1,2- Cl2 -HCl-2HCl1,4-1,2,3,4-1,4-1-3

*1 ----4

HOMO-----

*2

*3

*3

*5 --

6767

*6 Cl2I2 HNO3-HOAc80oCH2SO4>150oCC6H5NO2 , AlCl3H2SO4HNO3

4 C2H5OHC2H5OHC2H5OHNa/NH3()Na/NH3()Na/NH3()5 KMnO4

8.7 1

= 2.2D = 1.75D

:

370(1) * .2

(2)

3 psp2-sp2(1) 1973IRsp2

(2)A. *+ CH3(CH2)4ONOCH2Cl2H++ H2O + CH3(CH2)4OH+ CO2 + N2

B. 25-50oCM THF-MFM=Li, Mg+ CH3CH2CH2CH2Li-25-35oCLi-LiCleg 2eg 1

360oC NaNH210% NaOHC.

(3)A. eg 1B eg 2eg 3*ROH, RO-, RLi, NH3, RNH2 , RCOO-, RCHO+H+NaNH2

C

4A. 1NH3(l)NH3(l)NH3(l)NaNH2-NH22

3Na NH3(l)KNH2NH3(l)++

4 NH3(l)+KNH2 ArBr > ArI > ArCl >> ArFSN2Ar

Cl>>F C-XB. Br>I

C 1 2

8.9 1 4n + 2 ( n = 0, 1, 2..)

2

3 SbF5 SO2-75oC, -2Cl

SbF5, SO2-75oC, -2Cl- .

+ Ph3C+Br-AgNO3+ AgBrBr-189119541954HO3577123456

4HCCHNi(CN)215-20 atm, 50oC70%2KC-C1.40A*K

4 (2) 10- [10](CH)10(1) (CH)n n10

1 234n+210-C 14- 16- 18- (3)

5 -2Na+ H2 6

131.0D

6 4n+2

4n+2