OChem Tosylation Reaction: Predicting Major Product with p-TsOH Catalyst

  • Thread starter Adsit_Deus
  • Start date
In summary, the conversation discusses predicting the major product of a reaction involving a molecule with two -OH groups and the use of tosic acid. The main point of confusion is whether the tosic acid will replace one or both of the -OH groups. It is determined that the second -OH group is part of a carboxylic acid functional group and therefore must be treated differently. This clarification leads to a better understanding and resolution of the original doubts.
  • #1
Adsit_Deus
16
0

Homework Statement



Predict the major product in the following reaction (Hint: Consider intra-molecular reaction)

Homework Equations



HO2C-(CH2)3-CH(OH)-CH3 ------------cat. p-TsOH, heat----------> ?

The Attempt at a Solution



Essentially what I cannot figure out is if the tosic acid is going to replace the -OH group of the carboxylic acid, the other standalone -OH group, or both. I would assume that it would only replace one since the molecule would likely be more stable, and for that same reason I would also assume that it would replace the 2 prime -OH rather than the -OH attached to the carboxylic acid group.
 
Physics news on Phys.org
  • #2
Adsit_Deus said:

Homework Statement



Predict the major product in the following reaction (Hint: Consider intra-molecular reaction)

Homework Equations



HO2C-(CH2)3-CH(OH)-CH3 ------------cat. p-TsOH, heat----------> ?

The Attempt at a Solution



Essentially what I cannot figure out is if the tosic acid is going to replace the -OH group of the carboxylic acid, the other standalone -OH group, or both. I would assume that it would only replace one since the molecule would likely be more stable, and for that same reason I would also assume that it would replace the 2 prime -OH rather than the -OH attached to the carboxylic acid group.
A screenshot of the molecule in Marvin Sketch is attached
 

Attachments

  • Screen Shot 2015-01-17 at 2.08.22 PM.png
    Screen Shot 2015-01-17 at 2.08.22 PM.png
    30.1 KB · Views: 477
  • #3
Adsit_Deus said:
and for that same reason I would also assume that it would replace the 2 prime -OH rather than the -OH attached to the carboxylic acid group.
And, your doubts regarding your assumption are what?
 
  • #4
My original thought was stability, but I am not sure. We were never shown an example problem where there was any more than one -OH group in class, nor were we shown what could happen if there are two oxygen-centric functional groups. I just do not know how to go about dealing with them since we only worked one or two problems with run-of-the-mill 1 and 2 prime alcohols.
 
  • #5
The second "-OH" group you're worried about doesn't work as such; it's part of the carboxylic acid functional group and has to be treated as being part of that group rather as another alcohol group. Feel a little more comfortable?
 
  • #6
Extremely, thank you. I was mainly unsure of that exact point. "Is is still treated as a lone hydroxyl group, or is it treated as a part of a group that does not necessarily obey that tosylate rule?" That clears everything up.
 

1. What is the purpose of the tosylation reaction in organic chemistry?

The tosylation reaction, also known as the tosylate or tosyl chloride reaction, is a common method used in organic chemistry to introduce a tosyl group (-SO2CH3) onto a compound. This group serves as a leaving group in subsequent reactions, making the tosylation reaction a valuable tool in synthetic chemistry.

2. What is the role of p-TsOH in the tosylation reaction?

p-TsOH, or para-toluenesulfonic acid, is a catalyst used in the tosylation reaction. It helps to activate the leaving group and promote the substitution of the tosyl group onto the compound. It also helps to prevent side reactions and increase the yield of the desired product.

3. How do you predict the major product in a tosylation reaction?

The major product in a tosylation reaction can be predicted by considering the stability of the intermediate formed. Generally, the most stable intermediate will be the major product. Additionally, factors such as steric hindrance and electronic effects can also influence the product formation.

4. Can a tosylation reaction be used on any type of compound?

Tosylation reactions are commonly used on compounds with hydroxyl (-OH), amine (-NH2), and carboxylic acid (-COOH) functional groups. However, they can also be used on other types of compounds as long as they have a suitable leaving group for substitution.

5. Are there any limitations or drawbacks to using the tosylation reaction?

One limitation of the tosylation reaction is that it can only be used on compounds with a suitable leaving group. Additionally, the tosyl group can sometimes be difficult to remove in subsequent reactions, requiring harsh conditions. This can lead to unwanted side reactions and lower yields. Careful consideration of the compound and reaction conditions is necessary to overcome these limitations.

Similar threads

  • Biology and Chemistry Homework Help
Replies
28
Views
4K
  • Biology and Chemistry Homework Help
Replies
2
Views
1K
  • Biology and Chemistry Homework Help
Replies
1
Views
2K
  • Biology and Chemistry Homework Help
Replies
1
Views
5K
  • Biology and Chemistry Homework Help
Replies
2
Views
2K
  • Biology and Chemistry Homework Help
Replies
3
Views
8K
  • Biology and Chemistry Homework Help
Replies
4
Views
7K
Replies
2
Views
1K
  • Biology and Chemistry Homework Help
Replies
8
Views
3K
  • Biology and Chemistry Homework Help
Replies
4
Views
3K
Back
Top