PHENOL SYNTHESIS Chemistry Specialist

Chemistry Specialist: Alicia Hart
UC Davis - SASC
PHENOL SYNTHESIS
a) Nucleophilic Aromatic Substitution (NAS) - Ipso Substitition
X
OH
NO2
NO2
NaOH
NO2
NO2
OH (or another nucleophile like -NH2) subs in at the ipso position (C w/ the LG on it)
In general, occurs w/ an EWG (through resonance) in ortho and/or para position to the halogen
If EWG in meta position, N.R.
b) NAS - Benzyne Intermediate
X
OH
OH
1. NaOH, high T, high P
2. H3O+
+
OH subs in at the ipso position (C w/ the LG on it) AND next door to ipso (due to benzyne intermediate)
In general, occurs w/ an EWG (induction only) or EDG on it
EX Ipso or Benzyne?
Br
OH
F3C
F3C
NaOH
* went through benzyne intermediate, major product
has OH attacking next door to ipso bc negative charge in the intermediate
is stabilized on the C next to the EWG CF3 (via induction)
c) via Nitrosation of Aniline
N2
NH2
OH
H2O
NaNO2, H2SO4, 0 C
d) via Metal Catalyst
X
OH
Pd, KOH, PR3
e) Ether Cleavage
OH
OR
HX
+
RX

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