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Ch. 17 - Reactions at the Alpha-Carbon
Bruice - Organic Chemistry 8th Edition
Bruice8th EditionOrganic ChemistryISBN: 9780135213711당신이 사용하는 게 아니라요?교과서 변경
17장, 문제 20a

What aldol addition product is formed from each of the following compounds?
a. Structural formula of an aldehyde with a carbonyl group and a long carbon chain.

검증된 단계별 안내
1
Step 1: Identify the compound provided in the image. The structure is a ketone with an aldehyde functional group, specifically 4-methylpentanal.
Step 2: Recognize the reaction conditions. The presence of NaOH and H2O indicates that this is an aldol addition reaction, which involves the formation of a β-hydroxy carbonyl compound.
Step 3: Determine the enolate formation. Under basic conditions (NaOH), the α-hydrogen adjacent to the carbonyl group is abstracted, forming an enolate ion. The enolate is stabilized by resonance between the α-carbon and the carbonyl oxygen.
Step 4: Analyze the nucleophilic attack. The enolate ion acts as a nucleophile and attacks the carbonyl carbon of another molecule of 4-methylpentanal, forming a new C-C bond. This results in the formation of a β-hydroxy aldehyde.
Step 5: Write the structure of the aldol addition product. The product will have a hydroxyl group (-OH) on the β-carbon relative to the aldehyde group, and the new C-C bond will connect the α-carbon of one molecule to the carbonyl carbon of the other.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Aldol Addition

Aldol addition is a reaction between two carbonyl compounds, typically aldehydes or ketones, in the presence of a base, leading to the formation of a β-hydroxy aldehyde or ketone. This reaction involves the nucleophilic attack of an enolate ion on the carbonyl carbon of another molecule, resulting in a new carbon-carbon bond. The product can further undergo dehydration to form an α,β-unsaturated carbonyl compound.
추천 영상:
09:51
Crossed Aldol

Enolate Ion Formation

Enolate ions are formed when a carbonyl compound is deprotonated at the alpha carbon by a strong base, such as NaOH. This ion is resonance-stabilized and acts as a nucleophile in aldol reactions. The ability to form enolate ions is crucial for the aldol addition process, as it allows for the nucleophilic attack on another carbonyl compound, facilitating the formation of the aldol product.
추천 영상:
02:26
Formation of Enolates

Dehydration of Aldol Products

After the aldol addition, the β-hydroxy aldehyde or ketone can undergo dehydration, where a molecule of water is eliminated, resulting in the formation of an α,β-unsaturated carbonyl compound. This step is often favored under conditions of heat or in the presence of acid or base, and it enhances the stability of the product by forming a conjugated system. Understanding this dehydration step is essential for predicting the final products of aldol reactions.
추천 영상:
09:51
Crossed Aldol