Show how you would accomplish the following syntheses.
(c) benzene → p-methoxybenzaldehyde

검증된 단계별 안내

Step 1: Begin with benzene as the starting material. Perform a Friedel-Crafts acylation reaction using paraformaldehyde (CH2O) and an acid catalyst such as AlCl3 to introduce a formyl group (-CHO) at the para position relative to the benzene ring.

Step 2: Protect the aldehyde group by converting it into an acetal. React the aldehyde with methanol (CH3OH) in the presence of an acid catalyst (e.g., HCl) to form the dimethyl acetal derivative.

Step 3: Introduce the methoxy group (-OCH3) at the para position. Perform an electrophilic aromatic substitution reaction using methanol and a Lewis acid catalyst (e.g., AlCl3) to replace the hydrogen atom at the para position with the methoxy group.

Step 4: Deprotect the acetal group to regenerate the aldehyde. Use an acidic hydrolysis reaction (e.g., HCl in water) to convert the acetal back into the aldehyde group.

Step 5: Verify the structure of the final product, p-methoxybenzaldehyde, ensuring the methoxy group is at the para position relative to the aldehyde group on the benzene ring.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

영상 길이:

주요 개념

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

Electrophilic Aromatic Substitution (EAS)

Electrophilic Aromatic Substitution is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. This process is crucial for modifying aromatic compounds, such as benzene, to introduce various functional groups. Understanding the mechanism of EAS, including the role of the electrophile and the stability of the carbocation intermediate, is essential for synthesizing compounds like p-methoxybenzaldehyde.

Ortho/Para Directing Groups

In EAS reactions, substituents on the aromatic ring can influence the position where new groups are added. Electron-donating groups, such as methoxy (-OCH3), are ortho/para directing, meaning they favor substitution at the ortho or para positions relative to themselves. Recognizing how these directing effects operate is vital for predicting the outcome of the synthesis from benzene to p-methoxybenzaldehyde.

Formylation of Aromatic Compounds

Formylation is the introduction of a formyl group (-CHO) into an aromatic compound, typically achieved through the Vilsmeier-Haack reaction or the Gattermann-Koch reaction. This step is essential in the synthesis of p-methoxybenzaldehyde, as it allows for the conversion of the methoxy-substituted aromatic compound into the desired aldehyde. Understanding the conditions and reagents required for effective formylation is crucial for successful synthesis.

Show how you would accomplish the following syntheses. (c) benzene → p-methoxybenzaldehyde