EAS reactions Flashcards

1
Q

Mechanism in EAS:

  1. electrophile reagent + catalyst
  2. The more reactive electrophile attacks aromatic ring – formation of sigma complex or stabilized carbocation
  3. Loss of proton – regeneration of pi bonds and aromatic ring
A

Mechanism in EAS:

  1. electrophile reagent + catalyst
  2. The more reactive electrophile ATTACKED BY aromatic ring – formation of sigma complex or stabilized carbocation
  3. Loss of proton – regeneration of pi bonds and aromatic ring
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2
Q

Mechanism in EAS:

  1. electrophile reagent + catalyst
  2. The more reactive electrophile attacks aromatic ring – formation of sigma complex or stabilized carbocation
  3. Loss of proton – regeneration of pi bonds and aromatic ring
A

Mechanism in EAS:

  1. electrophile reagent + catalyst
  2. The more reactive electrophile ATTACKED BY aromatic ring – formation of sigma complex or stabilized carbocation
  3. Loss of proton – regeneration of pi bonds and aromatic ring
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3
Q

What are the EAS reaction?

A

-Halogenation: Bomination, Chlorination, Iodination
-Nitration
-Sulfonation
-Freidel Crafts: Alkylation
-Freidel Crafts:
Acylation

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4
Q

Bromination:

  • Electrophilic reagent
  • Catalyst
  • product
A

Br2
FeBr3
Bromobenzene

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5
Q

Chlorination:

  • Electrophilic reagent
  • Catalyst
  • product
A

Cl2
FeCL3
Chlorobenzene

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6
Q

Iodonation:

  • Electrophilic reagent
  • Catalyst
  • product
A

I2 /oxidation w HNO3 catalyst = I+

Iodobenzene

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7
Q

Nitration:

  • Electrophilic reagent
  • Catalyst
  • product
A

E reagent prepared by sulfuric acid H2SO4 w/ nitric acid HNO3 to form the Ereagent nitronium ion electrophile.

Product: Nitrobenzene

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8
Q

Formation of Aminobenze

A

Reaction with Zn, tin Sn, or Fe in dilute acid like HCl forms amino benzene

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9
Q

Sulfonation:

  • Electrophilic reagent
  • Catalyst
  • product
A

SO3
H2SO4
Benzenesulofnic acid

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10
Q

Friedel–Crafts Alkylation:

  • Electrophilic reagent
  • Catalyst
  • product
A
Alkyl halide (C-X)
AlCl3 lewis acid which produces the carbocation = electrophile

Product depend on the alkyl halide

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11
Q

Friedel–Crafts Acylation:

  • Electrophilic reagent
  • Catalyst
  • product
A
Carbocation from C-X + Lewis acid = Acylium ion (RC--O)
AlCl3
Phenyl Ketone (RCR)
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12
Q

Alkylation by Protonation of Alkenes

Alkene is protonated by?

A

HF, hydroflouride. Weak nucleophile and will not react to the carbocation.

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13
Q

Protonation of Alcohol

Catalyst?
Product

A

H2SO4 = Electrophile used is carbocation CH3CH2 protonated C

Ethylbenzene

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14
Q

What are the EAS reaction?

A

-Halogenation: Bomination, Chlorination, Iodination
-Nitration
-Sulfonation
-Freidel Crafts: Alkylation
-Freidel Crafts:
Acylation

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15
Q

Bromination:

  • Electrophilic reagent
  • Catalyst
  • product
A

Br2
FeBr3
Bromobenzene

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16
Q

Chlorination:

  • Electrophilic reagent
  • Catalyst
  • product
A

Cl2
FeCL3
Chlorobenzene

17
Q

Iodonation:

  • Electrophilic reagent
  • Catalyst
  • product
A

I2 /oxidation w HNO3 catalyst = I+

Iodobenzene

18
Q

Nitration:

  • Electrophilic reagent
  • Catalyst
  • product
A

E reagent prepared by sulfuric acid H2SO4 w/ nitric acid HNO3 to form the Ereagent nitronium ion electrophile.

Product: Nitrobenzene

19
Q

Formation of Aminobenze

A

Reaction with Zn, tin Sn, or Fe in dilute acid like HCl forms amino benzene

20
Q

Sulfonation:

  • Electrophilic reagent
  • Catalyst
  • product
A

SO3
H2SO4
Benzenesulofnic acid

21
Q

Halogens: Activating or Deactivating? What is the orientation?

A

Deactivating but the orientation ortho and para.

22
Q

Friedel–Crafts Acylation:

  • Electrophilic reagent
  • Catalyst
  • product
A
Carbocation from C-X + Lewis acid = Acylium ion (RC--O)
AlCl3
Phenyl Ketone (RCR)
23
Q

Alkylation by Protonation of Alkenes

Alkene is protonated by?

A

HF, hydroflouride. Weak nucleophile and will not react to the carbocation.

24
Q

Protonation of Alcohol

Catalyst?
Product

A

H2SO4 = Electrophile used is carbocation CH3CH2 protonated C

Ethylbenzene

25
Q

Limitations of Friedel–Crafts

Reaction fails if benzene has a substituent that is less deactivating than halogens

A

False.

Reaction fails if benzene has a substituent that is MORE deactivating than halogens.

26
Q

Limitations of Friedel–Crafts

Rearrangement causes Mixture of products

A

True. Formation of carbocation due to lone pairs. Results to low yield of monosubti benzene

27
Q

Effect of substituents on EAS reactions

A

Reactivity (act or deact) and direction of Orientation (o, m, p) of the electrophilic attack.

28
Q

Orientations

A

Ortho - 1,2
Meta - 1, 3
Para - 1, 4

29
Q

What is activating group?

A

Donating E, has high reactivity. Has Ortho and Para direction

30
Q

Alkyl groups stabilize sigma complex by resonance.

A

False. by INDUCTION.

Donates electron density through sigma bond.

31
Q

Lone pair of e- stabilize sigma complex by resonsance.

A

True.

32
Q

What is deactivating group?

A

Has low reactivity. Directs to meta position. It deactivates all positions on the ring but less in the meta position.

33
Q

For multiple substituents. Reaction is where?

A

In the position of the strongest activating substituent. Product could be mixtures.