Textbook Question
Predict the products of the following aldol condensations. Show the products both before and after dehydration.
(e)
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Ch. 22 - Condensations and Alpha Substitutions of Carbonyl Compounds
Wade9th EditionOrganic ChemistryISBN: 9780135213728
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Table of contents
- Ch.1 - Structure and Bonding107
- Ch. 2 - Acids and Bases; Functional Groups115
- Ch.3 - Structure and Stereochemistry of Alkanes100
- Ch.4 - The Study of Chemical Reactions99
- Ch.5 - Stereochemistry93
- Ch.6 - Alkyl Halides; Nucleophilic Substitution118
- Ch. 7 - Structure and Synthesis of Alkenes; Elimination158
- Ch.8 - Reactions of Alkenes171
- Ch.9 - Alkynes91
- Ch.10 - Structure and Synthesis of Alcohols143
- Ch.11 - Reactions of Alcohols104
- Ch. 12 - Infrared Spectroscopy and Mass Spectrometry22
- Ch. 13 - Nuclear Magnetic Resonance Spectroscopy45
- Ch. 14 - Ethers, Epoxides, and Thioethers72
- Ch. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy89
- Ch. 16 - Aromatic Compounds74
- Ch. 17 - Reactions of Aromatic Compounds126
- Ch. 18 - Ketones and Aldehydes193
- Ch. 19 - Amines129
- Ch. 20 - Carboxylic Acids77
- Ch. 21 - Carboxylic Acid Derivatives141
- Ch. 22 - Condensations and Alpha Substitutions of Carbonyl Compounds175
- Ch. 23 - Carbohydrates and Nucleic Acids93
- Ch. 24 - Amino Acids, Peptides, and Proteins54
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Wade 9th EditionCh. 22 - Condensations and Alpha Substitutions of Carbonyl CompoundsProblem 62b
Wade 9th EditionCh. 22 - Condensations and Alpha Substitutions of Carbonyl CompoundsProblem 62bChapter 22, Problem 62b
Predict the products of the following aldol condensations. Show the products both before and after dehydration.
(b) 
Verified step by step guidance1
Step 1: Identify the functional groups in the molecule. The given compound is a cyclic ketone with two carbonyl groups (C=O). These groups are reactive in aldol condensation reactions under acidic conditions.
Step 2: Determine the enolate formation. Under acidic conditions, one of the alpha-hydrogens adjacent to a carbonyl group is removed, forming an enolate ion. This enolate ion acts as a nucleophile in the reaction.
Step 3: Predict the nucleophilic attack. The enolate ion attacks the electrophilic carbonyl carbon of the other ketone group, forming a new carbon-carbon bond. This results in the formation of a β-hydroxyketone intermediate.
Step 4: Consider dehydration. Under acidic conditions, the β-hydroxyketone undergoes dehydration (loss of water) to form an α,β-unsaturated ketone. This step involves the elimination of a hydroxyl group (-OH) and a hydrogen atom from adjacent carbons.
Step 5: Draw the final products. The product before dehydration is the β-hydroxyketone, and the product after dehydration is the α,β-unsaturated ketone. Ensure the correct placement of double bonds and functional groups in the final structure.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Aldol Condensation
Aldol condensation is a reaction between aldehydes or ketones that contain at least one alpha-hydrogen. In this reaction, one molecule acts as a nucleophile and attacks the carbonyl carbon of another molecule, forming a beta-hydroxy aldehyde or ketone. This intermediate can then undergo dehydration to yield an α,β-unsaturated carbonyl compound, which is often the final product of the reaction.
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Dehydration Reaction
Dehydration in the context of aldol condensation refers to the elimination of a water molecule from the beta-hydroxy aldehyde or ketone intermediate. This step is crucial as it leads to the formation of a double bond between the alpha and beta carbons, resulting in a more stable conjugated system. The dehydration can occur under heat or acidic/basic conditions, facilitating the conversion to the final product.
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Product Prediction
Predicting the products of an aldol condensation involves understanding the structure of the starting materials and the mechanism of the reaction. By identifying the reactive sites (alpha-hydrogens and carbonyl groups) and considering the possible combinations of these molecules, one can determine the expected aldol product. Additionally, recognizing the conditions that favor dehydration helps in predicting the final product structure.
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Related Practice
Textbook Question
Predict the products of the following aldol condensations. Show the products both before and after dehydration.
(d)
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Textbook Question
Predict the products of the following aldol condensations. Show the products both before and after dehydration.
(a)
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Textbook Question
2. Indicate which compounds would be more than 99% deprotonated by a solution of sodium ethoxide in ethanol.
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Textbook Question
Predict the products of the following aldol condensations. Show the products both before and after dehydration.
(c)
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Textbook Question
1. Rank the following compounds in order of increasing acidity.
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