1. Benzene and Aromatic Compounds
Benzene and Aromaticity

6. Huckel’s Rule
a ring
planar
each atom supplies a p orbital for electron delocalization
number of delocalized electrons = 4n + 2, where n = 0, 1, 2, ...

7. 4n + 2 = 4
n = 0.5
not aromatic
antiaromatic

8. 4n + 2 = 8
n = 1.5
nonplanar
nonaromatic

9. 4n + 2 = 10
n = 2

24. 4n + 2 = 6

25. Nomenclature of Substituted Benzenes

26. Reactions of Aromatic Compounds
Electrophilic Aromatic Substitution

27. Reactions of Aromatic Compounds
Electrophilic Aromatic Substitution

31. Electrophiles: Carbocations
C=C + H+
ROH + H+
Friedel-Crafts alkylation: RCl + AlCl3

35. Electrophiles: Acylium Ions
Friedel-Crafts acylation

39. Electrophiles: Halogen
Br FeBr3

43. Electrophiles: NO2+
HNO H2SO4

46. Electrophiles: SO3

51. Acylbenzenes