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

12. Alcohols, Ethers, Epoxides and Thiols

Leaving Group Conversions Summary

Organic Chemistry

12. Alcohols, Ethers, Epoxides and Thiols

Leaving Group Conversions Summary

Previous problemNext problem

7:17 minutes

Problem 49a,b,c

Textbook Question

Predict the major products (including stereochemistry) when cis-3-methylcyclohexanol reacts with the following reagents.
(a) PBr₃
(b) SOCl₂
(c) Lucas reagent

Verified step by step guidance

Step 1: Analyze the structure of cis-3-methylcyclohexanol. It is a cyclohexane ring with a hydroxyl (-OH) group and a methyl (-CH3) group attached. The hydroxyl group is in the cis configuration relative to the methyl group, meaning both substituents are on the same side of the ring.

Step 2: For reaction (a) with PBr3 (phosphorus tribromide), understand that PBr3 is used to convert alcohols into alkyl bromides via an SN2 mechanism. The hydroxyl group will be replaced by a bromine atom. Since the reaction proceeds via inversion of configuration (due to the SN2 mechanism), the stereochemistry of the product will be inverted relative to the starting material.

Step 3: For reaction (b) with SOCl2 (thionyl chloride), recognize that SOCl2 converts alcohols into alkyl chlorides. This reaction typically proceeds via an SN2 mechanism when pyridine is present, leading to inversion of configuration. The hydroxyl group will be replaced by a chlorine atom, and the stereochemistry of the product will be inverted.

Step 4: For reaction (c) with Lucas reagent (a mixture of ZnCl2 and concentrated HCl), note that this reagent is used to convert alcohols into alkyl chlorides. The reaction mechanism depends on the type of alcohol. Since cis-3-methylcyclohexanol is a secondary alcohol, the reaction proceeds via an SN1 mechanism, forming a carbocation intermediate. The stereochemistry of the product will be racemic due to the planar nature of the carbocation intermediate.

Step 5: Summarize the major products for each reaction: (a) 3-bromo-3-methylcyclohexane with inverted stereochemistry, (b) 3-chloro-3-methylcyclohexane with inverted stereochemistry, and (c) racemic 3-chloro-3-methylcyclohexane due to the SN1 mechanism.

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.

Reactions of Alcohols

Alcohols can undergo various reactions, including substitution and elimination. In the presence of reagents like PBr3 and SOCl2, alcohols are converted into alkyl halides through nucleophilic substitution. Understanding the mechanism of these reactions is crucial for predicting the products formed, including the stereochemistry of the resulting compounds.

Stereochemistry

Stereochemistry refers to the spatial arrangement of atoms in molecules and how this affects their chemical behavior. In the case of cyclic compounds like cyclohexanol, the orientation of substituents can lead to different stereoisomers. Recognizing the stereochemical implications of reactions is essential for accurately predicting the major products, especially when dealing with chiral centers.

Lucas Test

The Lucas test is a qualitative test used to classify alcohols based on their reactivity with Lucas reagent (a mixture of zinc chloride and hydrochloric acid). This reagent facilitates the conversion of alcohols to alkyl chlorides, with tertiary alcohols reacting faster than secondary and primary. Understanding the Lucas test helps in predicting the outcome of reactions involving alcohols and their corresponding halides.

Watch next

Master Comparing and contrasting the Alcohol Conversions. with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

Using cyclohexanone as the starting material, describe how each of the following compounds can be synthesized:

Textbook Question

Both cis- and trans-2-methylcyclohexanol undergo dehydration in warm sulfuric acid to give 1-methylcyclohexene as the major alkene product. These alcohols can also be converted to alkenes by tosylation using TsCl and pyridine, followed by elimination using KOC(CH₃)₃ as a strong base. Under these basic conditions, the tosylate of cis-2-methylcyclohexanol eliminates to give mostly 1-methylcyclohexene, but the tosylate of trans-2-methylcyclohexanol eliminates to give only 3-methylcyclohexene. Explain how this stereochemical difference in reactants controls a regiochemical difference in the products of the basic elimination, but not in the acid-catalyzed elimination.

Textbook Question

Predict the major products (including stereochemistry) when cis-3-methylcyclohexanol reacts with the following reagents.

(d) concentrated HBr

(e) TsCl/pyridine, then NaBr

Textbook Question

Show how you would synthesize the following compounds. As starting materials, you may use any alcohols containing four or fewer carbon atoms, cyclohexanol, and any necessary solvents and inorganic reagents.

(g)

Textbook Question

Suggest how you would convert trans-4-methylcyclohexanol to

a. trans-1-chloro-4-methylcyclohexane.

b. cis-1-chloro-4-methylcyclohexane.

Textbook Question

What stereoisomers do the following reactions form?

Textbook Question

What stereoisomers do the following reactions form?

Textbook Question

When SOCl₂ is used in place of HCl, only one product results. Why are these conditions better?

Show more practices