Textbook Question
What are the products of the following reactions?
a.
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Ch. 18 - Reactions of Benzene and Substituted Benzenes
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
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Table of contents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 1)31
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 2)65
- Ch. 2 - Acids and Bases: Central to Understanding Organic Chemistry84
- Ch. 3 - An Introduction to Organic Compounds:Nomenclature, Physical Properties, and Structure183
- Ch. 4 - Isomers: The Arrangement of Atoms in Space121
- Ch. 5 - Alkenes: Structure, Nomenclature, and an Introduction to Reactivity • Thermodynamics and Kinetics83
- Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions175
- Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis119
- Ch. 8 - Delocalized Electrons: Their Effect on Stability, pKa, and the Products of a Reaction • Aromaticity and Electronic Effects: An Introduction to the Reactions of Benzene148
- Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides212
- Ch. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing Compounds131
- Ch. 11 - Organometallic Compounds60
- Ch. 12 - Radicals90
- Ch. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis Spectroscopy62
- Ch. 14 - NMR Spectroscopy95
- Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives123
- Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives141
- Ch. 17 - Reactions at the Alpha-Carbon101
- Ch. 18 - Reactions of Benzene and Substituted Benzenes144
- Ch. 19 - More About Amines • Reactions of Heterocyclic Compounds49
- Ch. 20 - The Organic Chemistry of Carbohydrates80
- Ch. 21 - Amino Acids, Peptides, and Proteins57
- Ch. 22 - Catalysis in Organic Reactions and in Enzymatic Reactions35
- Ch. 23 - The Organic Chemistry of the Coenzymes—Compounds Derived from Vitamins1
- Ch. 28 - Pericyclic Reactions58
Chapter 19, Problem 67b
b. Rank the same esters from most reactive to least reactive in the second slow step of a nucleophilic acyl substitution reaction (collapse of the tetrahedral intermediate).
Verified step by step guidance1
Step 1: Understand the context of nucleophilic acyl substitution. The second slow step involves the collapse of the tetrahedral intermediate, where the leaving group departs and the carbonyl group reforms. The reactivity depends on the stability of the leaving group and the electronic effects of substituents on the ester.
Step 2: Analyze the substituents attached to the aromatic ring or alkyl group in each ester. Electron-withdrawing groups (EWGs) stabilize the negative charge on the leaving group, making the collapse of the tetrahedral intermediate faster. For example, chlorine atoms are strong EWGs.
Step 3: Compare the esters: (A) has a single chlorine substituent on the aromatic ring, (B) has no aromatic ring and is an alkyl ester, (C) has an unsubstituted aromatic ring, and (D) has two chlorine substituents on the aromatic ring. The presence of EWGs (like chlorine) on the aromatic ring increases reactivity.
Step 4: Rank the esters based on the number and position of EWGs. Ester D, with two chlorine substituents, is the most reactive due to the strong electron-withdrawing effect. Ester A, with one chlorine substituent, is next. Ester C, with an unsubstituted aromatic ring, follows. Ester B, an alkyl ester, is the least reactive as it lacks EWGs.
Step 5: Conclude the ranking: D > A > C > B. This ranking is based on the electronic effects of substituents influencing the stability of the leaving group during the collapse of the tetrahedral intermediate.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Nucleophilic Acyl Substitution
Nucleophilic acyl substitution is a fundamental reaction in organic chemistry where a nucleophile attacks the carbonyl carbon of an acyl compound, leading to the formation of a tetrahedral intermediate. This intermediate can collapse, resulting in the substitution of the leaving group (often an alcohol or halide) with the nucleophile. Understanding this mechanism is crucial for predicting the reactivity of different acyl compounds, such as esters.
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01:47
Nucleophiles and Electrophiles can react in Substitution Reactions.
Reactivity of Esters
The reactivity of esters in nucleophilic acyl substitution is influenced by the nature of the substituents attached to the carbonyl carbon. Electron-withdrawing groups, such as halogens, increase the electrophilicity of the carbonyl carbon, making the ester more reactive. Conversely, electron-donating groups can decrease reactivity. Thus, analyzing the substituents on the esters in the question is essential for ranking their reactivity.
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02:39Ester Nomenclature
Tetrahedral Intermediate Stability
The stability of the tetrahedral intermediate formed during nucleophilic acyl substitution plays a significant role in determining the overall reaction rate. Factors such as steric hindrance and electronic effects from substituents can affect the stability of this intermediate. A more stable intermediate will lead to a slower collapse and thus a slower reaction, while an unstable intermediate will collapse more readily, indicating higher reactivity.
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Related Practice
Textbook Question
Use the four compounds shown below to answer the following questions:
b. Why is o-fluorobenzoic acid the weakest of the ortho-halo-substituted benzoic acids?
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Textbook Question
A mixture of 0.10 mol benzene and 0.10 mol p-xylene was allowed to react with 0.10 mol nitronium ion until all the nitronium ion was gone. Two products were obtained: 0.002 mol of one and 0.098 mol of the other.
b. Why was more of one product obtained than of the other?
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Textbook Question
a. Rank the following esters from most reactive to least reactive in the first slow step of a nucleophilic acyl substitution reaction (formation of the tetrahedral intermediate):
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Textbook Question
Use the four compounds shown below to answer the following questions:
a. Why are the ortho-halo-substituted benzoic acids stronger acids than benzoic acid?
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Textbook Question
Does m-xylene or p-xylene react more rapidly with Cl2 + FeCl3? Explain your answer.
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