Why does the epoxide not react?

  • Thread starter Saitama
  • Start date
In summary: If it's not stable as you say, then why the epoxide ring is formed in the product?Alkoxide is a strong nucleophile, and Cl is an excellent leaving group, so it will just leave and epoxide will form. This is step 2, different story altogether.
  • #1
Saitama
4,243
93

Homework Statement


https://www.box.com/s/qs19ng6qvcget7g69ad3 [Broken]

Homework Equations


The Attempt at a Solution


I think that there are two possibilities. First, C2H5O- can attack at the epoxide ring by the SN2 mechanism (i guess the attack will take place at the less substituted carbon in the epoxide ring) and the second is that nucleophilic substitution can place at the carbon attached to oxygen by the SN2 mechanism.
But which of the two possibilities would happen and why? I am stuck here.

The answer given is D but why does the epoxide ring does not react?

Any help is appreciated. :smile:
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
Epoxide ring is reacting. See, in the question, Epoxide was on C-14 atom, but in the answer you mentioned, Epoxide is not on C-14 atom.

Here's my take.

C1%2520-%2520Copy.png
 
Last edited:
  • #3
AGNuke said:
Epoxide ring is reacting. See, in the question, Epoxide was on C-14 atom, but in the answer you mentioned, Epoxide is not on C-14 atom.

Here's my take.

C1%2520-%2520Copy.png

I too was thinking that the neighbouring group mechanism would follow but why doesn't nucleophilic subsitution take place at the carbon attached to Cl?
 
  • #4
Pranav-Arora said:
I too was thinking that the neighbouring group mechanism would follow but why doesn't nucleophilic subsitution take place at the carbon attached to Cl?
If you are talking for the first step, my guess would be that the major product formed will be from the reaction which is easier to proceed and the result is more stable.

In the case of epoxide, you can see that sp3 carbon with bond angle 60° is not the best idea for stability. So, the major product should involve in breaking this epoxide ring, so it happens in Step 1.

It is another story that Intramolecular SN2 happens in Step 2. Basic Environment causes the formation of Alkoxide ion, which is highly reactive and a strong Nucleophile. So, it forms epoxide at the cost of Cl atom leaving. Intramolecular SN2 Substitution
 
Last edited:
  • #5
AGNuke said:
In the case of epoxide, you can see that sp3 carbon with bond angle 60° is not the best idea for stability. So, the major product should involve in breaking this epoxide ring, so it happens in Step 1.

If it's not stable as you say, then why the epoxide ring is formed in the product?
 
  • #6
Read the next line. Alkoxide is a strong nucleophile, and Cl is an excellent leaving group, so it will just leave and epoxide will form. This is step 2, different story altogether.

Who said that "less" stable products can't be formed. And I didn't said epoxide not stable. Only "Less" stable, owing to the account the angle strain of sp3 bonds.
 

What is an epoxide?

An epoxide is a three-membered ring compound with an oxygen atom bonded to two adjacent carbon atoms.

What causes epoxide to not react?

Epoxides are highly strained molecules due to the three-membered ring structure. This strain makes it difficult for the molecule to undergo reactions, resulting in low reactivity.

Why do some reactions with epoxide fail?

The high reactivity of epoxides can also cause them to react with other molecules in the reaction mixture before the desired reaction can occur. This can lead to side reactions and failure of the main reaction.

Is there a way to increase the reactivity of epoxides?

Yes, there are several methods to increase the reactivity of epoxides, such as using a catalyst or using an acid or base to open the ring and activate the molecule.

What are some common reactions involving epoxides?

Epoxides are commonly used in organic synthesis reactions, such as the Williamson ether synthesis, where an epoxide is opened with an alcohol to form an ether. They are also used in the synthesis of alcohols, amines, and carboxylic acids.

Similar threads

Replies
11
Views
2K
Replies
5
Views
3K
  • Biology and Chemistry Homework Help
Replies
2
Views
2K
  • Biology and Chemistry Homework Help
Replies
2
Views
1K
  • Computing and Technology
2
Replies
52
Views
3K
  • Biology and Chemistry Homework Help
Replies
1
Views
6K
  • Biology and Chemistry Homework Help
Replies
4
Views
4K
  • Biology and Chemistry Homework Help
Replies
4
Views
7K
  • Biology and Chemistry Homework Help
Replies
2
Views
2K
  • Biology and Chemistry Homework Help
Replies
2
Views
2K
Back
Top