Skip to main content
Ch. 17 - Reactions at the Alpha-Carbon
Bruice - Organic Chemistry 8th Edition
Bruice8th EditionOrganic ChemistryISBN: 9780135213711Not the one you use?Change textbook
Chapter 18, Problem 66c

Indicate how each of the following compounds can be synthesized from the given starting material and any other necessary reagents:
c. Synthesis reaction showing acetoacetic ester converting to a cyclohexane derivative with specified reagents.

Verified step by step guidance
1
Step 1: Analyze the starting material and the target compound. The starting material is an ethyl acetoacetate derivative, and the target compound is a ketone with a cyclohexyl group attached. This suggests that a nucleophilic substitution followed by cyclization is required.
Step 2: Perform an alkylation reaction on the ethyl acetoacetate derivative. Use a suitable alkyl halide, such as bromocyclohexane, and a strong base like sodium ethoxide (NaOEt) to deprotonate the alpha-carbon of the starting material. This generates a nucleophilic enolate ion that can attack the alkyl halide, forming a new C-C bond.
Step 3: Hydrolyze the ester group in the alkylated product. Use acidic or basic hydrolysis conditions to convert the ester group into a carboxylic acid. This step prepares the molecule for decarboxylation.
Step 4: Decarboxylate the carboxylic acid under heating conditions. This step removes the carboxyl group, leaving behind the desired ketone structure with the cyclohexyl group attached.
Step 5: Purify the final product using appropriate techniques such as distillation or recrystallization to isolate the target ketone compound.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2m
Was this helpful?

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 forming ketones through the reaction of an acetoacetic ester with an alkyl halide. This process involves the enolate ion of the acetoacetic ester attacking the alkyl halide, leading to the formation of a new carbon-carbon bond. The resulting compound can then undergo hydrolysis and decarboxylation to yield a ketone.
Recommended video:
01:28
Synthesis of Amino Acids: Acetamidomalonic Ester Synthesis Example 2

Enolate Chemistry

Enolates are reactive intermediates formed from the deprotonation of carbonyl compounds, such as esters or ketones. They are crucial in nucleophilic addition reactions, where they can act as nucleophiles to attack electrophiles. Understanding enolate stability and reactivity is essential for predicting the outcomes of reactions involving acetoacetic esters and other carbonyl compounds.
Recommended video:
Guided course
02:26
Formation of Enolates

Reagents and Reaction Conditions

The choice of reagents and reaction conditions significantly influences the outcome of organic reactions. In acetoacetic ester synthesis, common reagents include strong bases (like sodium ethoxide) for deprotonation and alkyl halides for alkylation. Additionally, controlling temperature and solvent can affect the reaction rate and selectivity, making it vital to understand these factors for successful synthesis.
Recommended video:
Related Practice
Textbook Question

Indicate how each of the following compounds can be synthesized from the given starting material and any other necessary reagents:

b.

1
views
Textbook Question

The Reformatsky reaction is an addition reaction in which an organozinc reagent is used instead of a Grignard reagent to add to the carbonyl group of an aldehyde or a ketone. Because the organozinc reagent is less reactive than a Grignard reagent, a nucleophilic addition to the ester group does not occur.

The organozinc reagent is prepared by treating an α-bromo ester with zinc.

Describe how each of the following compounds can be prepared, using a Reformatsky reaction:

c.

1
views
Textbook Question

The ketone whose 1H NMR spectrum is shown here was obtained as the product of an acetoacetic ester synthesis. What alkyl halide was used in the synthesis?

<IMAGE>

2
views
Textbook Question

The Reformatsky reaction is an addition reaction in which an organozinc reagent is used instead of a Grignard reagent to add to the carbonyl group of an aldehyde or a ketone. Because the organozinc reagent is less reactive than a Grignard reagent, a nucleophilic addition to the ester group does not occur. The organozinc reagent is prepared by treating an α-bromo ester with zinc.

Describe how each of the following compounds can be prepared, using a Reformatsky reaction:

a.

5
views
Textbook Question

There are other condensation reactions similar to the aldol and Claisen condensations:

c. The Knoevenagel condensation is the condensation of an aldehyde or a ketone that has no a-hydrogens and a compound such as diethyl malonate that has an a-carbon flanked by two electron-withdrawing groups. Draw the product obtained from the following Knoevenagel condensation:

2
views
Textbook Question

What product is obtained when the product of a Knoevenagel condensation is heated in an aqueous acidic solution?

6
views