Question

Predict the major products of the following reactions.(e) p-methylanisole + acetyl chloride + AlCl3

Accepted Answer

Identify the type of reaction: This is a Friedel-Crafts acylation reaction, where an aromatic compound reacts with an acyl chloride in the presence of a Lewis acid catalyst (AlCl₃). The reaction introduces an acyl group (-COCH₃) onto the aromatic ring. Analyze the structure of p-methylanisole: p-Methylanisole has two substituents on a benzene ring: a methoxy group (-OCH₃) and a methyl group (-CH₃) in the para position relative to each other. Both groups are electron-donating and activate the ring towards electrophilic substitution, directing incoming groups to the ortho and para positions relative to themselves. Determine the most reactive positions: The methoxy group is a stronger electron-donating group than the methyl group, so it will dominate the directing effects. The ortho and para positions relative to the methoxy group are the most reactive. However, the para position relative to the methoxy group is already occupied by the methyl group, so the acyl group will primarily add to the ortho positions relative to the methoxy group. Generate the intermediate: The acetyl chloride (CH₃COCl) reacts with AlCl₃ to form the acylium ion (CH₃C⁺=O), which is the electrophile in this reaction. This electrophile will attack the most reactive positions on the aromatic ring, leading to the formation of a sigma complex (arenium ion). Complete the reaction: The sigma complex will lose a proton to regenerate the aromaticity of the ring, resulting in the major product. The major product will be p-methylanisole with an acetyl group (-COCH₃) added to the ortho position relative to the methoxy group.

Predict the major products of the following reactions.
(e) p-methylanisole + acetyl chloride + AlCl₃

비슷한 문제에 대한 검증된 영상 답변:

주요 개념

Electrophilic Aromatic Substitution

Activating and Deactivating Groups

Regioselectivity