Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

21. Aldehydes and Ketones: Nucleophilic Addition

DIBAL

Organic Chemistry

21. Aldehydes and Ketones: Nucleophilic Addition

DIBAL

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Problem 40b

Textbook Question

The esters shown differ only by the alkoxy group.
(i) Predict the product(s) obtained when these react with DIBAl-H.
(ii) Based on your answer, in a sequence like this, would there ever be a need to convert from one ester to another?
(b)

Verified step by step guidance

Identify the ester functional group in the given compound. The ester is characterized by the presence of a carbonyl group (C=O) adjacent to an alkoxy group (O-R).

Understand the role of DIBAl-H (Diisobutylaluminum hydride) in the reaction. DIBAl-H is a reducing agent that selectively reduces esters to aldehydes at low temperatures, such as -78°C.

Predict the product of the reaction. When the ester reacts with DIBAl-H, the alkoxy group is replaced by a hydrogen atom, converting the ester into an aldehyde.

Consider the need to convert from one ester to another. Since DIBAl-H reduces the ester to an aldehyde, the specific alkoxy group in the ester does not affect the final aldehyde product. Therefore, there is generally no need to convert from one ester to another in this sequence.

Conclude that the reaction with DIBAl-H is efficient for reducing esters to aldehydes without the need for altering the alkoxy group, as the alkoxy group does not influence the final product in this context.

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Key Concepts

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

DIBAl-H Reactivity

DIBAl-H (Diisobutylaluminum hydride) is a selective reducing agent commonly used in organic chemistry to reduce esters to aldehydes. Understanding its reactivity is crucial, as it allows chemists to predict the outcome of reactions involving esters. When an ester reacts with DIBAl-H, the carbonyl group is reduced, while the alkoxy group remains intact, leading to the formation of an aldehyde.

Alkoxy Group Influence

The alkoxy group in an ester can significantly influence the reactivity and properties of the compound. Different alkoxy groups can affect steric hindrance and electronic effects, which in turn can alter the reaction pathways and products formed during chemical reactions. Recognizing how these groups interact with reagents like DIBAl-H is essential for predicting reaction outcomes.

Ester Interconversion

Ester interconversion refers to the process of transforming one ester into another, often involving changes in the alkoxy group. This can be necessary for various synthetic strategies, especially when specific reactivity or selectivity is required in subsequent reactions. Understanding the conditions and mechanisms for ester interconversion is important for effective synthetic planning in organic chemistry.

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