Textbook Question
Show how the following compounds can be made using the malonic ester synthesis.
(a) 3-phenylpropanoic acid
(b) 2-methylpropanoic acid
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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 50
Wade 9th EditionCh. 22 - Condensations and Alpha Substitutions of Carbonyl CompoundsProblem 50Chapter 22, Problem 50
Show how the following ketones might be synthesized by using the acetoacetic ester synthesis.
Verified step by step guidance1
Step 1: Understand the acetoacetic ester synthesis. This is a method used to synthesize ketones by alkylating the enolate ion of ethyl acetoacetate (acetoacetic ester) followed by hydrolysis and decarboxylation. The general reaction involves three main steps: enolate formation, alkylation, and decarboxylation.
Step 2: For each ketone (a), (b), and (c), identify the carbon skeleton and determine the alkyl group(s) that need to be added to the acetoacetic ester. This involves analyzing the structure of the target ketone and breaking it down into the acetoacetic ester precursor and the alkyl halide(s) required for alkylation.
Step 3: Write the reaction mechanism for the synthesis of each ketone. Start with the deprotonation of the acetoacetic ester using a strong base (e.g., ethoxide ion) to form the enolate ion. Then, show the nucleophilic attack of the enolate ion on the appropriate alkyl halide to form the alkylated acetoacetic ester.
Step 4: Perform hydrolysis and decarboxylation. After alkylation, the alkylated acetoacetic ester is hydrolyzed under acidic or basic conditions to form a β-keto acid. This β-keto acid then undergoes decarboxylation (loss of CO₂) upon heating to yield the desired ketone.
Step 5: Repeat the process for each ketone (a), (b), and (c), ensuring that the correct alkyl halides and reaction conditions are used for each case. Verify that the final product matches the structure of the target ketone.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acetoacetic Ester Synthesis
Acetoacetic ester synthesis is a method for synthesizing ketones through the reaction of an acetoacetic ester with an alkyl halide. This process involves the formation of a β-keto ester, which can be hydrolyzed and decarboxylated to yield the desired ketone. It is particularly useful for creating ketones with a specific carbon chain length and branching.
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Nucleophilic Substitution
Nucleophilic substitution is a fundamental reaction mechanism in organic chemistry where a nucleophile attacks an electrophile, resulting in the replacement of a leaving group. In the context of acetoacetic ester synthesis, the nucleophile is typically the enolate ion formed from the acetoacetic ester, which attacks the alkyl halide to form a new carbon-carbon bond.
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Enolate Ion Formation
Enolate ions are reactive intermediates formed when a deprotonated carbon adjacent to a carbonyl group (like in acetoacetic ester) becomes negatively charged. This species is crucial in acetoacetic ester synthesis as it acts as a nucleophile in the substitution reaction, allowing for the introduction of new alkyl groups and ultimately leading to the formation of the target ketone.
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Related Practice
Textbook Question
Show how the following compounds can be made using the malonic ester synthesis.
(c) 4-phenylbutanoic acid
(d) cyclopentanecarboxylic acid
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Textbook Question
In Solved Problem 22-9, the target molecule was synthesized using a Michael addition to form the bond that is β,γ to the upper carbonyl group. Another approach is to use a Michael addition to form the bond that is β,γ to the other (lower) carbonyl group. Show how you would accomplish this alternative synthesis.
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Textbook Question
Show the ketones that would result from hydrolysis and decarboxylation of the following β-keto esters.
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Textbook Question
Show how an acetoacetic ester synthesis might be used to form a δ-diketone such as heptane-2,6-dione.
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Textbook Question
Show how cyclohexanone might be converted to the following δ-diketone (Hint: Stork).
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