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

24. Enolate Chemistry: Reactions at the Alpha-Carbon

Acetoacetic Ester Synthesis

Organic Chemistry

24. Enolate Chemistry: Reactions at the Alpha-Carbon

Acetoacetic Ester Synthesis

Previous problemNext problem

Problem 41a

Textbook Question

What alkyl bromide should be used in the acetoacetic ester synthesis of each of the following methyl ketones? a. 2-pentanone

Verified step by step guidance

Step 1: Understand the acetoacetic ester synthesis. This reaction involves the alkylation of ethyl acetoacetate (a β-keto ester) followed by hydrolysis and decarboxylation to produce a methyl ketone. The key step is identifying the alkyl bromide that will introduce the desired alkyl group to the β-keto ester.

Step 2: Analyze the target molecule, 2-pentanone. The structure of 2-pentanone is CH3-CO-CH2-CH2-CH3. This indicates that the methyl ketone has a CH3 group on one side of the carbonyl and a CH2CH2CH3 group on the other side.

Step 3: Recognize that the CH3 group comes from the ethyl acetoacetate itself. The remaining CH2CH2CH3 group must be introduced via alkylation using an appropriate alkyl bromide.

Step 4: Determine the alkyl bromide needed. To add the CH2CH2CH3 group, the alkyl bromide should be 1-bromopropane (CH3CH2CH2Br). This will react with the enolate of ethyl acetoacetate during the alkylation step.

Step 5: Summarize the process. The synthesis involves deprotonating ethyl acetoacetate to form the enolate, reacting it with 1-bromopropane to introduce the CH2CH2CH3 group, and then performing hydrolysis and decarboxylation to yield 2-pentanone.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

Key Concepts

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

Acetoacetic Ester Synthesis

Acetoacetic ester synthesis is a method for forming ketones through the reaction of an acetoacetic ester with an alkyl halide. This reaction involves the nucleophilic substitution of the ester enolate with the alkyl halide, leading to the formation of a new carbon-carbon bond. Understanding this process is crucial for determining the appropriate alkyl bromide to use for synthesizing specific ketones.

Enolate Formation

Enolate formation is a key step in acetoacetic ester synthesis, where a base abstracts a proton from the alpha carbon of the acetoacetic ester, generating a resonance-stabilized enolate ion. This enolate can act as a nucleophile, attacking the electrophilic carbon of the alkyl halide. Recognizing how to generate and utilize enolates is essential for predicting the outcome of the synthesis.

Alkyl Halides

Alkyl halides, such as alkyl bromides, are organic compounds containing a carbon atom bonded to a halogen atom. The choice of alkyl halide in acetoacetic ester synthesis affects the structure of the resulting ketone. Understanding the reactivity and structure of different alkyl halides is important for selecting the correct one to achieve the desired methyl ketone from the synthesis.

Watch next

Master General Reactions with a bite sized video explanation from Johnny

Start learning