Homework Help is Here – Start Your Trial Now!
Science
Chemistry
4. Aldehydes and ketones can be "protected" as acetals and ketals. Complete the following outlined reactions, showing how the protection is accomplished, and what results after deprotection. Br „MgBr 1) Br 2) H3O* deprotection here

4. Aldehydes and ketones can be "protected" as acetals and ketals. Complete the following outlined reactions, showing how the protection is accomplished, and what results after deprotection. Br „MgBr 1) Br 2) H3O* deprotection here

Chemistry
Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
See similar textbooks
icon
Related questions
icon
Concept explainers
Question
### Protection of Aldehydes and Ketones as Acetals and Ketals Aldehydes and ketones can be "protected" as acetals and ketals. Complete the following outlined reactions, showing how the protection is accomplished, and what results after deprotection. 1. **Starting material:** A benzene ring with a bromomethyl (—CH₂Br) substituent and an aldehyde (—CHO) group attached directly to the ring. 2. **Formation of Acetal:** - The carbonyl group (aldehyde) reacts with a diol (ethylene glycol, C₂H₄(OH)₂) to form a cyclic acetal (with an oxygens in a five-membered ring). - This reaction effectively "protects" the carbonyl group by transforming it into an acetal, which is more stable under basic conditions and prevents it from undergoing unwanted side reactions. 3. **Grignard Reaction:** - The bromo substituent reacts with magnesium (Mg) to form a Grignard reagent (R—MgBr), where R is the benzene ring attached to the oxygens of the acetal. 4. **Reaction with Aldehyde/Ketone:** - The Grignard reagent reacts with a carbonyl compound (another aldehyde or ketone group) leading to the formation of a new carbon-carbon bond. 5. **Deprotection:** - The cyclic acetal is then hydrolyzed (broken down) back to the original carbonyl group using aqueous acid (H₃O⁺), completing the deprotection step, revealing the original functional group. ### Diagram Explanation - The initial chemical structure consists of a benzene ring with a bromomethyl and an aldehyde group. - The aldehyde is protected by forming a cyclic acetal with ethylene glycol. - The bromine is replaced by a Grignard reagent (MgBr). - The Grignard reagent reacts with a new carbonyl compound to form an intermediate. - Finally, the cyclic acetal is hydrolyzed to restore the aldehyde group, completing the deprotection. Complete the reactions to show the final product after deprotection, illustrating the transformation and the utility of protection groups in synthetic organic chemistry.
Transcribed Image Text:### Protection of Aldehydes and Ketones as Acetals and Ketals Aldehydes and ketones can be "protected" as acetals and ketals. Complete the following outlined reactions, showing how the protection is accomplished, and what results after deprotection. 1. **Starting material:** A benzene ring with a bromomethyl (—CH₂Br) substituent and an aldehyde (—CHO) group attached directly to the ring. 2. **Formation of Acetal:** - The carbonyl group (aldehyde) reacts with a diol (ethylene glycol, C₂H₄(OH)₂) to form a cyclic acetal (with an oxygens in a five-membered ring). - This reaction effectively "protects" the carbonyl group by transforming it into an acetal, which is more stable under basic conditions and prevents it from undergoing unwanted side reactions. 3. **Grignard Reaction:** - The bromo substituent reacts with magnesium (Mg) to form a Grignard reagent (R—MgBr), where R is the benzene ring attached to the oxygens of the acetal. 4. **Reaction with Aldehyde/Ketone:** - The Grignard reagent reacts with a carbonyl compound (another aldehyde or ketone group) leading to the formation of a new carbon-carbon bond. 5. **Deprotection:** - The cyclic acetal is then hydrolyzed (broken down) back to the original carbonyl group using aqueous acid (H₃O⁺), completing the deprotection step, revealing the original functional group. ### Diagram Explanation - The initial chemical structure consists of a benzene ring with a bromomethyl and an aldehyde group. - The aldehyde is protected by forming a cyclic acetal with ethylene glycol. - The bromine is replaced by a Grignard reagent (MgBr). - The Grignard reagent reacts with a new carbonyl compound to form an intermediate. - Finally, the cyclic acetal is hydrolyzed to restore the aldehyde group, completing the deprotection. Complete the reactions to show the final product after deprotection, illustrating the transformation and the utility of protection groups in synthetic organic chemistry.
Expert Solution
steps

Step by step

Solved in 2 steps with 1 images

SEE SOLUTIONCheck out a sample Q&A here
Blurred answer
Knowledge Booster
Ethers
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
Chemistry
Chemistry
Chemistry
ISBN:
9781305957404
Author:
Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:
Cengage Learning
Chemistry
Chemistry
Chemistry
ISBN:
9781259911156
Author:
Raymond Chang Dr., Jason Overby Professor
Publisher:
McGraw-Hill Education
Principles of Instrumental Analysis
Principles of Instrumental Analysis
Chemistry
ISBN:
9781305577213
Author:
Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:
Cengage Learning
Organic Chemistry
Organic Chemistry
Chemistry
ISBN:
9780078021558
Author:
Janice Gorzynski Smith Dr.
Publisher:
McGraw-Hill Education
Chemistry: Principles and Reactions
Chemistry: Principles and Reactions
Chemistry
ISBN:
9781305079373
Author:
William L. Masterton, Cecile N. Hurley
Publisher:
Cengage Learning
Elementary Principles of Chemical Processes, Bind…
Elementary Principles of Chemical Processes, Bind…
Chemistry
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY
SEE MORE TEXTBOOKS