Chapter 12 Electrophilic Aromatic Substitution rxns sections 12'312'7

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Chapter 12Electrophilic Aromatic
Substitution(rxns sections 12.3-12.7)
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Energy Diagram for EAS Mechanism ( ref. Section
12.2)
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Example of a Synthesis Using EAS Reactions (
ref. Section 12.16)
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Problems with the Friedel-Crafts Alkylation
Reaction ( ref. Sections 12.6 12.8)
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Friedel-Crafts Alkylation is subject to
rearrangments
What is the product here?

(CH3)2CHCH2Cl
Isobutyl chloride
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Rearrangements in Friedel-Crafts Alkylation

• t-butyl cation is the electrophile so you see
  a rearrangement here

(CH3)2CHCH2Cl
Isobutyl chloride
tert-Butylbenzene(66)
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Friedel-Crafts Acylation of Benzene
What is the product here?
O
AlCl3

CH3CH2CCl
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Friedel-Crafts Acylation of Benzene
O
O
CCH2CH3
AlCl3

CH3CH2CCl

HCl
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However you need two steps Acylation Reduction
Acylate the ring , then reduce the carbonyl
using the Clemmensen reduction or
RCCl
AlCl3
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Acylation-Reduction
Acylate the ring , then reduce the carbonyl
using the Wolff_Kishner reduction
RCCl
H2NNH2, KOH,triethylene glycol,heat
AlCl3
CH2R