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

10. Addition Reactions

Addition Reaction

Organic Chemistry

10. Addition Reactions

Addition Reaction

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4:15 minutes

Problem 42a

Textbook Question

Using any necessary inorganic reagents, show how you would convert acetylene and isobutyl bromide to
(a) meso-2,7-dimethyloctane-4,5-diol, (CH₃)₂CHCH₂CH(OH)CH(OH)CH₂CH(CH₃)₂.

Verified step by step guidance

Step 1: Deprotonate acetylene (C₂H₂) using a strong base such as sodium amide (NaNH₂) to generate the acetylide ion (C≡C⁻). This ion is a strong nucleophile and will be used in the next step.

Step 2: Perform an alkylation reaction by reacting the acetylide ion with isobutyl bromide ((CH₃)₂CHCH₂Br). This will result in the formation of 2-methyl-1-butyne ((CH₃)₂CHCH₂C≡CH).

Step 3: Perform a second alkylation reaction. Deprotonate the terminal alkyne in 2-methyl-1-butyne using NaNH₂ to form another acetylide ion. Then react this ion with another equivalent of isobutyl bromide to form 2,7-dimethyloct-3-yne ((CH₃)₂CHCH₂C≡CCH₂CH(CH₃)₂).

Step 4: Reduce the triple bond in 2,7-dimethyloct-3-yne to a cis-alkene using Lindlar's catalyst. This will yield cis-2,7-dimethyloct-3-ene ((CH₃)₂CHCH₂CH=CHCH₂CH(CH₃)₂).

Step 5: Perform a syn-dihydroxylation of the cis-alkene using reagents such as osmium tetroxide (OsO₄) followed by hydrogen peroxide (H₂O₂). This will add hydroxyl groups (-OH) to the 4th and 5th carbons, resulting in meso-2,7-dimethyloctane-4,5-diol ((CH₃)₂CHCH₂CH(OH)CH(OH)CH₂CH(CH₃)₂).

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Key Concepts

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

Alkyne Reactivity

Acetylene is a simple alkyne that can undergo various reactions, including hydrogenation and nucleophilic addition. Understanding the reactivity of alkynes is crucial for converting them into more complex molecules. In this case, acetylene can be transformed into a more functionalized compound through reactions with inorganic reagents, which can facilitate the formation of alcohols in the final product.

Nucleophilic Substitution

Nucleophilic substitution is a fundamental reaction mechanism in organic chemistry where a nucleophile replaces a leaving group in a molecule. In this question, isobutyl bromide serves as a substrate for nucleophilic attack, which is essential for forming the desired alcohols in the final product. Understanding the conditions that favor either SN1 or SN2 mechanisms will help in predicting the outcome of the reaction.

Stereochemistry

Stereochemistry involves the study of the spatial arrangement of atoms in molecules and how this affects their chemical behavior. The target compound, meso-2,7-dimethyloctane-4,5-diol, has specific stereochemical requirements, including the presence of chiral centers and a plane of symmetry. Recognizing how to control stereochemistry during synthesis is vital for achieving the correct configuration in the final product.

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Related Practice

Textbook Question

Show how you might use olefin metathesis to assemble the following alkenes from smaller units:

(a)

(b)

Textbook Question

Starting with ethyne, describe how the following compounds can be synthesized:

a. (3S,4R)-4-bromo-3-hexanol and (3R,4S)-4-bromo-3-hexanol

Multiple Choice

Predict the major organic product of the following reaction.

Textbook Question

Synthesize the following molecules beginning with only organic molecules containing three carbons or fewer.

(g)

Textbook Question

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

a. ethyl bromide

b. tert-butyl bromide

c. formaldehyde

Textbook Question

Show how you would accomplish the following synthetic conversions.

c. 1-methylcyclopentanol → 2-chloro-1-methylcyclopentanol

Problem-Solving Hint: The opening of a halonium ion is driven by its electrophilic nature. The weak nucleophile attacks the carbon bearing more positive charge.

Textbook Question

Using 1,2-dimethylcyclohexene as your starting material, show how you would synthesize the following compounds. (Once you have shown how to synthesize a compound, you may use it as the starting material in any later parts of this problem.) If a chiral product is shown, assume that it is part of a racemic mixture.

(h)

Textbook Question

Show what products you would expect from the following metathesis reactions, using the Schrock or Grubbs catalysts.

(a)

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