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

25. Condensation Chemistry

Claisen-Schmidt Condensation

Organic Chemistry

25. Condensation Chemistry

Claisen-Schmidt Condensation

Previous problemNext problem

4:55 minutes

Problem 84a

Textbook Question

What reagents are required to carry out the following synthesis?

Verified step by step guidance

Step 1: Analyze the first transformation (A). The starting material is benzene, and the product is benzaldehyde. This transformation involves the introduction of a formyl group (-CHO) onto the benzene ring. The reaction is typically carried out using the Gattermann-Koch formylation method, which requires carbon monoxide (CO), hydrogen chloride (HCl), and a catalyst such as aluminum chloride (AlCl₃).

Step 2: Analyze the second transformation (B). The starting material is benzaldehyde, and the product is cinnamaldehyde. This transformation involves the formation of a conjugated double bond between the benzene ring and the aldehyde group. This is typically achieved through an aldol condensation reaction, where benzaldehyde reacts with acetaldehyde in the presence of a base such as sodium hydroxide (NaOH) or potassium hydroxide (KOH).

Step 3: For the aldol condensation, ensure that the reaction conditions favor the formation of the α,β-unsaturated aldehyde (cinnamaldehyde). This involves using a catalytic amount of base and controlling the temperature to avoid side reactions.

Step 4: After the aldol condensation, the product may require purification. Techniques such as distillation or recrystallization can be used to isolate cinnamaldehyde from the reaction mixture.

Step 5: Verify the overall synthesis pathway by ensuring that the reagents and conditions used in each step are compatible and lead to the desired product without undesired side reactions.

Verified video answer for a similar problem:

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

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Claisen-Schmidt Condensation

The Claisen-Schmidt condensation is a reaction between an aldehyde and a ketone in the presence of a base, leading to the formation of an α,β-unsaturated carbonyl compound. This reaction is a type of aldol condensation where one of the reactants is an aldehyde, and the other is a ketone. Understanding this mechanism is crucial for identifying the reagents needed for the synthesis shown in the question.

Reagents for Claisen-Schmidt Condensation

The typical reagents required for a Claisen-Schmidt condensation include a strong base, such as sodium ethoxide or sodium hydroxide, and the appropriate aldehyde and ketone. The base deprotonates the aldehyde, generating an enolate ion that can then attack the carbonyl carbon of the ketone, facilitating the condensation reaction. Identifying these reagents is essential for successfully carrying out the synthesis depicted in the image.

Enolate Ion Formation

Enolate ions are formed when a base abstracts a proton from the α-carbon of a carbonyl compound, resulting in a resonance-stabilized anion. This enolate can act as a nucleophile in various reactions, including the Claisen-Schmidt condensation. Understanding how enolate ions are generated and their role in nucleophilic attacks is vital for comprehending the overall reaction mechanism and predicting the products of the synthesis.

Watch next

Master Claisen-Schmidt Reaction with a bite sized video explanation from Johnny

Start learning