Why Activating Groups Speed Up Ortho and Para

Activating groups on an aromatic ring can speed up electrophilic substitution and direct new groups to the ortho and para positions. Excluding halogens, these ortho-para directors are electron-donating groups. They make the ring carbons more electron-rich and more reactive.

A clear example is ani...

With the exception of halogens, all ortho–para directors are known as activating groups as they increase the reactivity of the aromatic ring towards electrophilic substitution.

For instance, nitration of anisole is faster than benzene under comparable conditions.

Recall that electrophilic aromatic substitution inv...