Compounds undergoing Friedel-Crafts alkylation

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    Organic chemistry
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Discussion Overview

The discussion revolves around the ability of various compounds to undergo Friedel-Crafts alkylation, focusing on the influence of substituents such as NH2 and CH3 groups on reactivity. Participants explore the conditions under which certain compounds can participate in this reaction, including the role of catalysts like AlCl3.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that the 2nd, 3rd, and 6th compounds can undergo Friedel-Crafts alkylation, while the 4th compound cannot.
  • One participant questions the reactivity of the 4th compound, noting its NH2 group and comparing it to the 2nd compound with a CH3 group.
  • Another participant suggests that the NH2 group loses its lone pair in the presence of AlCl3, forming an NH3+ cation, which is highly deactivating.
  • It is proposed that the CH3 group in the 2nd compound is activating and does not donate electrons, allowing for the substitution reaction to proceed.
  • Clarifications are made regarding the role of the chlorine substituent in the 2nd compound, indicating that it is not the chlorine that is removed during the reaction.

Areas of Agreement / Disagreement

Participants express differing views on the reactivity of the 4th compound compared to the 2nd compound, with no consensus reached on the underlying reasons for these differences.

Contextual Notes

Participants discuss the effects of substituents on reactivity without resolving the implications of lone pair donation or the specific roles of activating versus deactivating groups in Friedel-Crafts alkylation.

jolly_math
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Homework Statement
Which of the following compounds can undergo Friedel-Crafts alkylation?
Relevant Equations
Friedel-Crafts alkylation
1713022840300.png

The answer is that the 2nd, 3rd and 6th compounds can undergo Friedel-Crafts alkylation.

I don't understand why the 4th compound cannot undergo a Friedel-Crafts alkylation reaction, but the 2nd compound can. It has an activating NH2 group and a weakly deactivating Br group, and it's similar to the 2nd compound which has an activating CH3 group and a weakly deactivating Cl group – what makes it different?

Thank you.
 
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What happens to the NH2 group in the presence of the Friedel-Crafts catalyst?
 
jolly_math said:
Homework Statement: Which of the following compounds can undergo Friedel-Crafts alkylation?
Relevant Equations: Friedel-Crafts alkylation

View attachment 343324
The answer is that the 2nd, 3rd and 6th compounds can undergo Friedel-Crafts alkylation.

I don't understand why the 4th compound cannot undergo a Friedel-Crafts alkylation reaction, but the 2nd compound can. It has an activating NH2 group and a weakly deactivating Br group, and it's similar to the 2nd compound which has an activating CH3 group and a weakly deactivating Cl group – what makes it different?

Thank you.
The thing is the 4th compound has a NH2 group which has a lone pair but in presence of AlCl3 a strong electrophile , the NH2 gives up its lone pair and forms NH3+ cation which is a -M group and highly deactivating, but in the 2nd compound CH3 have activating nature and cannot give any electrons so the chlorine gets removed and CH3 gets added i think
 
PhysicsEnjoyer31415 said:
The thing is the 4th compound has a NH2 group which has a lone pair but in presence of AlCl3 a strong electrophile , the NH2 gives up its lone pair and forms NH3+ cation which is a -M group and highly deactivating, but in the 2nd compound CH3 have activating nature and cannot give any electrons so the chlorine gets removed and CH3 gets added i think
Im sorry but to clarify , not the chlorine on the compound
 

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