Reações de Compostos Aromáticos

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Solutions for Reactions of Aromatic Compounds
20 continued
C CH2CH2CH3
O
Cl
C CH2CH2CH3
O
CH2CH2CH2CH3
(g)
1) AlCl3
2) H2O
workup
Zn(Hg), HCl
HNO3
H2SO4
NO2
Fe
HCl
NH2
O
O O
"Ac2O"
NH
O
(h)
O
Cl
AlCl3
NH
O
H3C
O
This reaction appears in 
text section 12—sorry!
Another example of this 
amide reacting by E.A.S. 
is Problem 10(c).
H2O workup
+
F
C
AB
BA
HC
F Nuc
NO2
NO2
21 Another way of asking this question is this: Why is fluoride ion a good leaving group from A but not 
from B (either by SN1 or SN2)? Nuc = a nucleophile
Nuc
Formation of the anionic sigma complex A is the rate-determining (slow) step in nucleophilic aromatic 
substitution. The loss of fluoride ion occurs in a subsequent fast step where the nature of the leaving group 
does not affect the overall reaction rate. In the SN1 or SN2 mechanisms, however, the carbon-fluorine bond 
is breaking in the rate-determining step, so the poor leaving group ability of fluoride does indeed affect the 
rate.
en
er
gy
en
er
gy
en
er
gy
BB
A
nucleophilic aromatic 
substitution
SN1
F – leaves—
fast
F – leaves—
slow
F – leaves—
slow
SN2
Clemmensen
394