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

14. Synthetic Techniques

Alkynide Alkylation

Organic Chemistry

14. Synthetic Techniques

Alkynide Alkylation

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5:06 minutes

Problem 52b

Textbook Question

Show how each of the following compounds can be prepared using the given starting material, any needed inorganic reagents, and any organic compound that has no more than four carbons:
b.

Verified step by step guidance

Step 1: Begin with the starting material, acetylene (HC≡CH). Perform a hydroboration reaction using diborane (B2H6) to convert the alkyne into an alkene. This reaction will yield ethene (CH2=CH2).

Step 2: Perform a Markovnikov addition of HBr to ethene. This reaction will produce bromoethane (CH3CH2Br).

Step 3: React bromoethane with magnesium in dry ether to form the Grignard reagent, ethylmagnesium bromide (CH3CH2MgBr).

Step 4: Prepare propanal (CH3CH2CHO) by oxidizing propanol (CH3CH2CH2OH) using PCC (pyridinium chlorochromate). Propanol is an organic compound with no more than four carbons.

Step 5: React the Grignard reagent (CH3CH2MgBr) with propanal (CH3CH2CHO) to form the desired product, 2-bromo-3-methylbutane (CH3CH2CHCH3 with a Br substituent). This reaction involves nucleophilic addition followed by protonation.

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Key Concepts

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

Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. Understanding the functional groups present in both the starting material and the target compounds is essential for determining the appropriate reactions and reagents needed for synthesis.

Reaction Mechanisms

Reaction mechanisms describe the step-by-step process by which reactants are converted into products. Familiarity with common mechanisms, such as nucleophilic substitution or elimination reactions, is crucial for predicting how to transform the starting material into the desired compounds using the specified reagents.

Synthesis Strategies

Synthesis strategies involve planning a series of chemical reactions to construct a target molecule from simpler starting materials. This includes selecting appropriate reagents, considering reaction conditions, and ensuring that the overall pathway is efficient and feasible, especially when limited to organic compounds with four or fewer carbons.

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Related Practice

Textbook Question

How can the following compounds be prepared using ethyne as the starting material?

Textbook Question

Show how each of the following compounds can be synthesized from the given starting materials:

Textbook Question

Suggest a method for synthesizing the following alkynes using an alkyne and an alkyl halide. [There are two correct answers for each product.]

(c)

Textbook Question

When doing synthesis, you will often find yourself repeating the same series of steps. To see this in action, synthesize the following aldehydes beginning with an organic molecule containing three carbons or fewer.

(d)

Textbook Question

Show how each of the following compounds can be synthesized from the given starting materials:

Textbook Question

Predict the products formed when CH₃CH₂–C≡C:^–Na⁺ reacts with the following compounds.

(d) cyclohexanone

(e) CH₃CH₂CH₂CHO

Textbook Question

The application box in the margin of states, “The addition of an acetylide ion to a carbonyl group is used in the synthesis of ethchlorvynol, a drug used to cause drowsiness and induce sleep.” Show how you would accomplish this synthesis from acetylene and a carbonyl compound.

Textbook Question

Show how the following compounds can be prepared, using ethyne as one of the starting materials:

1. 1-pentyn-3-ol

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