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

22. Carboxylic Acid Derivatives: NAS

Nucleophilic Acyl Substitution

Organic Chemistry

22. Carboxylic Acid Derivatives: NAS

Nucleophilic Acyl Substitution

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5:36 minutes

Problem 44d,e,f

Textbook Question

Predict the major products formed when benzoyl chloride (PhCOCl) reacts with the following reagents.
(d) anisole and aluminum chloride
(e) excess phenylmagnesium bromide, then dilute acid
(f) LiAlH(O-t-Bu)₃

Verified step by step guidance

Step 1: For part (d), recognize that the reaction involves anisole (methoxybenzene) and aluminum chloride (AlCl₃). This is a Friedel-Crafts acylation reaction. Benzoyl chloride (PhCOCl) will react with AlCl₃ to form an acylium ion (PhCO⁺), which is the electrophile in this reaction. The methoxy group (-OCH₃) on anisole is an electron-donating group, activating the aromatic ring and directing the electrophile to the ortho and para positions.

Step 2: For part (e), identify that the reaction involves excess phenylmagnesium bromide (a Grignard reagent) followed by dilute acid. The carbonyl group in benzoyl chloride (PhCOCl) is highly reactive toward nucleophiles. The Grignard reagent will attack the carbonyl carbon, forming a tetrahedral intermediate. Since excess Grignard reagent is present, a second equivalent will react with the intermediate to form a tertiary alcohol after acid workup.

Step 3: For part (f), understand that LiAlH(O-t-Bu)₃ is a bulky reducing agent. It selectively reduces acid chlorides (like benzoyl chloride) to aldehydes without further reducing the aldehyde to an alcohol. The steric hindrance of the bulky tert-butoxy groups prevents over-reduction.

Step 4: For part (d), predict the major products by considering the regioselectivity of the Friedel-Crafts acylation. The acylium ion (PhCO⁺) will add to the ortho and para positions of anisole, but the para product is typically favored due to steric hindrance at the ortho position.

Step 5: For parts (e) and (f), confirm the products by analyzing the reaction mechanisms. In part (e), the final product is a tertiary alcohol formed after the Grignard reagent reacts twice with the carbonyl group. In part (f), the product is benzaldehyde, as the reduction stops at the aldehyde stage due to the bulky reducing agent.

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Key Concepts

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

Electrophilic Aromatic Substitution

Electrophilic aromatic substitution (EAS) is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. In the case of benzoyl chloride reacting with anisole in the presence of aluminum chloride, the electrophilic carbon of the benzoyl group can react with the nucleophilic aromatic ring of anisole, leading to the formation of a substituted product.

Grignard Reagents

Grignard reagents, such as phenylmagnesium bromide, are highly reactive organomagnesium compounds that act as nucleophiles. When excess phenylmagnesium bromide reacts with benzoyl chloride, it can attack the carbonyl carbon, leading to the formation of a tertiary alcohol after subsequent acid workup. Understanding the reactivity of Grignard reagents is crucial for predicting the products of such reactions.

Reduction Reactions

Reduction reactions involve the gain of electrons or the decrease in oxidation state of a molecule. In the context of the reaction with LiAlH(O-t-Bu)3, a selective reducing agent, the carbonyl group of benzoyl chloride is reduced to a corresponding alcohol. This concept is essential for understanding how different reducing agents can selectively convert functional groups in organic compounds.

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