Propose products (if any) and mechanisms for the following AlCl 3 -catalyzed reactions: a. chlorocyclohexane with benzene

Welcome back. Every once in another video, propose a mechanism and identify the products formed when benzene undergoes iron three bromide catalyze reaction with Bromy Oben. So let's go ahead and draw Bromy Pens. We can start by drawing a five member drain and we are going to add our bromo group. Now, this structure essentially is going to react with iron three bromide. We're going to observe in a Luis acid Lewis base reaction. Let's remember that we are forming a complex. So essentially what we want to do is draw the result on complex understanding that iron three bromide has a free the orbital in which it can accept those electrons coming from bromine, right. So we're going to to the resultant complex. Now, let's go ahead and bond bromine to iron. And from here, we understand that iron gets a formal negative charge and bromine gets a formal positive charge. This essentially allows us to weaken the carbon bromine bond. We can form a carbo cion. However, it's not a very stable secondary carbo carion that we can form, right. However, we are weakening the bond and this is where we are going to perform the attack right. Specifically, we want to draw a benzene and we're going to draw the nucleic attack on the electro pilic carbon. And the electro pilic carbon is directly bonded to bromine. So we're going to observe a nucleic attack, followed by the loss of the leaving group here, we're going to form iron with four bromine atoms attached to it. Iron still has a formal negative charge. And now the next structure that we're getting is our sigma complex. So we can essentially take benzene, we're breaking our pipe band. That's because we are essentially attaching our five member grain. Now, we have formed a carbo cion that's really important to understand. So we're going to add a positive charge on carbon. And our final step is the de protonation step. We want to restore aromatic, right. And to do that, we are just going to draw hydrogen and we essentially need a base. Let's expand the structure of Febr four. We also have to understand that the sigma complex is a resonance stabilized, but there is definitely no necessity to draw out the resonance forms. Essentially, we are interested in only one form. So it's sufficient to have just one. Let's draw the bromine atoms bonded to iron. And now we're essentially going to have the electron transfer in the formation of H pr. This allows us to restore the catalyst iron three bromide we're also forming H PR and of course, our final product. Well, then we have our final mechanism. So let's label it as our final answer. Thank you for watching.

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1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
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19. Reactions of Aromatics: EAS and Beyond

EAS:Friedel-Crafts Alkylation Mechanism

Organic Chemistry

19. Reactions of Aromatics: EAS and Beyond

EAS:Friedel-Crafts Alkylation Mechanism

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5:05 minutes

Problem 15a

Textbook Question

Propose products (if any) and mechanisms for the following AlCl₃-catalyzed reactions:
a. chlorocyclohexane with benzene

Verified step by step guidance

Step 1: Recognize that this reaction involves Friedel-Crafts alkylation, a common electrophilic aromatic substitution reaction catalyzed by AlCl₃. The chlorocyclohexane serves as the alkylating agent, and benzene acts as the aromatic substrate.

Step 2: Understand the role of AlCl₃. It acts as a Lewis acid and interacts with the chlorine atom in chlorocyclohexane, forming a complex that generates a cyclohexyl carbocation (C₆H₁₁⁺). This carbocation is the electrophile in the reaction.

Step 3: Benzene, as an aromatic compound, has a high electron density in its π-system. The cyclohexyl carbocation attacks the benzene ring, leading to the formation of a sigma complex (arenium ion). This intermediate temporarily disrupts the aromaticity of benzene.

Step 4: The sigma complex undergoes deprotonation at the site of electrophilic attack, restoring the aromaticity of benzene. The final product is cyclohexylbenzene (C₆H₅-C₆H₁₁).

Step 5: Regenerate the AlCl₃ catalyst. The chloride ion (Cl⁻) released during the deprotonation step combines with the AlCl₃ complex to reform AlCl₄⁻, ensuring the catalyst is available for further reactions.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Electrophilic Aromatic Substitution

Electrophilic aromatic substitution (EAS) is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. In this context, the benzene acts as a nucleophile, attacking the electrophile generated from chlorocyclohexane in the presence of AlCl3, which enhances the electrophilicity of the chlorocyclohexane.

Lewis Acid Catalysis

Lewis acid catalysis involves the use of a Lewis acid, such as AlCl3, to facilitate chemical reactions by accepting an electron pair. In this reaction, AlCl3 coordinates with the chlorine atom of chlorocyclohexane, forming a more reactive carbocation that can then participate in the electrophilic aromatic substitution with benzene.

Carbocation Stability

Carbocation stability is crucial in determining the outcome of reactions involving carbocations. The stability of the carbocation formed during the reaction influences the likelihood of substitution occurring. In this case, the stability of the carbocation generated from chlorocyclohexane will affect the efficiency of the electrophilic attack on the benzene ring.

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