Undesired polysubstitution of an aromatic nucleus is most likely to be encountered in the case of:

Understand the Problem

The question is asking which method is most likely to lead to undesired polysubstitution of an aromatic nucleus in organic chemistry. It presents several options related to electrophilic aromatic substitution reactions.

More Information

Friedel-Crafts alkylation involves introducing alkyl groups to an aromatic ring, which activates the ring and can lead to multiple substitutions. The electron-donating nature of alkyl groups increases the reactivity of the phenyl ring, leading to further substitutions.

Tips

A common mistake is confusing alkylation with acylation. Acylation actually reduces the reactivity of the aromatic ring, preventing polysubstitution.

Sources

• Undesired polysubstitution of an aromatic nucleus is | Chegg - chegg.com
• Undesired polysubstitution of a benzene ring | Study.com - homework.study.com