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

Cyanohydrin

Organic Chemistry

21. Aldehydes and Ketones: Nucleophilic Addition

Cyanohydrin

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1:15 minutes

Problem 16a

Textbook Question

Show how you would accomplish the following syntheses.
(a) acetophenone → acetophenone cyanohydrin

Verified step by step guidance

Identify the functional group transformation: The problem involves converting acetophenone (a ketone) into acetophenone cyanohydrin (a cyanohydrin, which contains both a hydroxyl group and a nitrile group attached to the same carbon). This transformation is a nucleophilic addition reaction.

Recall the mechanism of cyanohydrin formation: Cyanohydrins are formed when a ketone reacts with hydrogen cyanide (HCN) in the presence of a catalytic amount of a base, such as NaOH or KCN. The base deprotonates HCN to generate the cyanide ion (CN⁻), which acts as the nucleophile.

Write the reaction conditions: Add HCN to acetophenone in the presence of a catalytic base. The cyanide ion (CN⁻) will attack the carbonyl carbon of acetophenone, forming a tetrahedral intermediate.

Explain the intermediate step: The tetrahedral intermediate will have a negatively charged oxygen atom. This oxygen atom will then be protonated by HCN or another proton source in the reaction mixture, resulting in the formation of the cyanohydrin.

Summarize the product: The final product is acetophenone cyanohydrin, which has a hydroxyl group (-OH) and a nitrile group (-C≡N) attached to the same carbon atom that was originally part of the carbonyl group in acetophenone.

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Key Concepts

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

Nucleophilic Addition

Nucleophilic addition is a fundamental reaction in organic chemistry where a nucleophile attacks an electrophilic carbon atom, leading to the formation of a new bond. In the case of synthesizing acetophenone cyanohydrin, the nucleophile (cyanide ion) attacks the carbonyl carbon of acetophenone, resulting in the formation of a cyanohydrin. Understanding this mechanism is crucial for predicting the products of reactions involving carbonyl compounds.

Carbonyl Compounds

Carbonyl compounds, characterized by the presence of a carbonyl group (C=O), include aldehydes and ketones. Acetophenone is a ketone, and its reactivity is largely due to the electrophilic nature of the carbonyl carbon. Recognizing the properties and reactivity of carbonyl compounds is essential for understanding their transformations, such as the conversion to cyanohydrins.

Cyanohydrin Formation

Cyanohydrin formation involves the addition of hydrogen cyanide (HCN) to a carbonyl compound, resulting in a compound that contains both a hydroxyl group (-OH) and a nitrile group (-CN). This reaction is significant in organic synthesis as cyanohydrins can serve as intermediates for further transformations. Knowing the conditions and mechanisms for cyanohydrin formation is vital for successfully synthesizing acetophenone cyanohydrin.

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