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

13. Alcohols and Carbonyl Compounds

Nucleophilic Addition

Organic Chemistry

13. Alcohols and Carbonyl Compounds

Nucleophilic Addition

Previous problemNext problem

1:56 minutes

Problem 75c,d

Textbook Question

What product is formed when 3-methyl-2-cyclohexenone reacts with each of the following reagents?
c. HBr
d. CH₃CH₂SH

Verified step by step guidance

Identify the structure of 3-methyl-2-cyclohexenone. It is a cyclohexenone ring with a methyl group attached to the third carbon and a double bond between carbons 2 and 3. The carbonyl group is located at carbon 1.

For part (c), HBr is a strong acid and a source of bromide ions (Br⁻). The reaction will proceed via electrophilic addition to the double bond. The proton (H⁺) from HBr will add to the less substituted carbon of the double bond (Markovnikov's rule), forming a carbocation intermediate at the more substituted carbon.

The bromide ion (Br⁻) will then attack the carbocation, resulting in the formation of a bromo-substituted product. The final product will have a bromine atom attached to the more substituted carbon of the original double bond.

For part (d), CH3CH2SH is a thiol (a sulfur-containing compound). In the presence of a base or acidic catalyst, the thiol can act as a nucleophile. The carbonyl group in 3-methyl-2-cyclohexenone is electrophilic and can undergo nucleophilic addition. The sulfur atom of CH3CH2SH will attack the carbonyl carbon, forming a thioether (sulfur-containing compound) as the product.

Ensure to draw the structures of the products for both reactions to visualize the changes. For part (c), the product will have a bromine atom added to the cyclohexenone ring. For part (d), the product will have a CH3CH2S group attached to the former carbonyl carbon.

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.

Electrophilic Addition

Electrophilic addition is a fundamental reaction mechanism in organic chemistry where an electrophile reacts with a nucleophile, typically involving alkenes or alkynes. In the case of 3-methyl-2-cyclohexenone reacting with HBr, the double bond acts as a nucleophile, attacking the electrophilic hydrogen, leading to the formation of a bromoalkane. Understanding this mechanism is crucial for predicting the products of reactions involving unsaturated compounds.

Nucleophilic Substitution

Nucleophilic substitution is a reaction where a nucleophile replaces a leaving group in a molecule. When 3-methyl-2-cyclohexenone reacts with CH3CH2SH, the sulfur atom acts as a nucleophile, attacking the carbon atom bonded to the leaving group (if present) or the carbonyl carbon. This concept is essential for understanding how different nucleophiles can interact with electrophilic centers in organic compounds.

Regioselectivity

Regioselectivity refers to the preference of a chemical reaction to occur at one location over another in a molecule, leading to the formation of a specific product. In the reactions of 3-methyl-2-cyclohexenone with HBr and CH3CH2SH, the regioselectivity will determine which carbon atom the electrophile or nucleophile will bond to, influencing the final product's structure. Recognizing regioselectivity is vital for predicting the outcomes of organic reactions.

Watch next

Master Nucleophilic Addition with a bite sized video explanation from Johnny

Start learning