Textbook Question
Draw the enol tautomers for each of the following compounds. For compounds that have more than one enol tautomer, indicate the one that is more stable.
f.
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Ch. 17 - Reactions at the Alpha-Carbon
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 18, Problem 5c
Rank the compounds in each of the following groups from strongest acid to weakest acid:
c. 
Verified step by step guidance1
Step 1: Analyze the functional groups present in each compound. Compound (a) contains a ketone group (C=O), compound (b) contains an ester group (C=O and C-O), and compound (c) contains an amide group (C=O and NH).
Step 2: Recall the general trend in acidity for these functional groups. Ketones are less acidic compared to esters, and amides are generally the least acidic due to the electron-donating nature of the nitrogen atom.
Step 3: Consider the resonance stabilization of the conjugate base formed after deprotonation. Esters can stabilize the conjugate base better than ketones due to the additional oxygen atom, while amides have reduced resonance stabilization due to the nitrogen's lone pair.
Step 4: Evaluate the inductive effects. The electronegativity of oxygen in esters contributes to a stronger inductive effect, increasing acidity compared to ketones. In amides, the nitrogen's lone pair reduces the inductive effect, making them less acidic.
Step 5: Rank the compounds based on their acidity: Compound (b) (ester) is the strongest acid, followed by compound (a) (ketone), and compound (c) (amide) is the weakest acid.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acidity and pKa
Acidity in organic chemistry is often measured by the pKa value, which indicates the strength of an acid. A lower pKa value corresponds to a stronger acid, meaning it can donate protons (H+) more readily. Understanding the relationship between structure and acidity is crucial for ranking compounds based on their acidic strength.
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07:45
Identifying pKa values
Resonance Stabilization
Resonance stabilization occurs when a molecule can be represented by multiple valid Lewis structures, allowing for the delocalization of electrons. This delocalization can stabilize the conjugate base formed after deprotonation, enhancing the acidity of the original compound. Compounds with greater resonance stabilization of their conjugate bases tend to be stronger acids.
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03:43The radical stability trend.
Inductive Effect
The inductive effect refers to the electron-withdrawing or electron-donating influence of substituents on a molecule. Electronegative atoms or groups can stabilize negative charges on conjugate bases through inductive withdrawal, increasing acidity. Conversely, electron-donating groups can destabilize the conjugate base, leading to weaker acids.
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01:47Understanding the Inductive Effect.
Related Practice
Textbook Question
Draw the enol tautomers for each of the following compounds. For compounds that have more than one enol tautomer, indicate the one that is more stable.
d.
e.
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Textbook Question
Explain why the -hydrogen of an N,N-disubstituted amide is less acidic (pKa = 30) than the -hydrogen of an ester (pKa = 25).
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Textbook Question
Rank the compounds in each of the following groups from strongest acid to weakest acid:
a.
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Textbook Question
Explain why a base can remove a proton from the α-carbon of N,N-dimethylethanamide but not from the α-carbon of either N-methylethanamide or ethanamide.
Textbook Question
Explain why 92% of 2,4-pentanedione exists as the enol tautomer in hexane but only 15% of this compound exists as the enol tautomer in water.
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