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

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SUMMARY

The discussion focuses on predicting the major product of a tosylation reaction involving HO2C-(CH2)3-CH(OH)-CH3 with p-TsOH as a catalyst. Participants clarify that the -OH group attached to the carboxylic acid is not treated as a standalone hydroxyl group but as part of the carboxylic acid functional group. Consequently, the tosylation will likely occur at the secondary -OH group rather than the carboxylic acid -OH, leading to a more stable product. This understanding is crucial for accurately predicting the outcome of the reaction.

PREREQUISITES
  • Understanding of tosylation reactions and their mechanisms
  • Familiarity with carboxylic acids and alcohol functional groups
  • Knowledge of p-TsOH (p-toluenesulfonic acid) as a catalyst
  • Experience with intramolecular reactions in organic chemistry
NEXT STEPS
  • Study the mechanism of tosylation reactions in detail
  • Learn about the stability of reaction intermediates in organic synthesis
  • Explore examples of intramolecular reactions involving multiple functional groups
  • Investigate the role of p-TsOH in various organic transformations
USEFUL FOR

Chemistry students, organic chemists, and anyone interested in understanding the intricacies of tosylation reactions and their applications in organic synthesis.

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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.
 
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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
 

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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?
 
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.
 
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?
 
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.
 

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