How does an amino, or an hydroxyl group substituted onto a phenyl ring influence the reactivity of the ring?
1 Answer
It activates the ring towards electrophilic substitution.......
Explanation:
Consider substitution of
And so for phenol, or aniline, the substituting group, nitrogen, or oxygen, is MORE electronegative than carbon, however, the lone pairs of electrons on the oxygen or nitrogen atoms are conceived to be delocalized into the carbocycle, and make the ring MORE reactive in electrophilic substitution reactions. Because electron density is donated to the phenyl ring, the
Note that hydroxyl or amine substitution activates all of the carbons on the ring, however, the ortho and para positions, are PARTICULARLY activated due to the resonance effects, i.e. the lone pair on the oxygen or nitrogen can be delocalized to these positions and make this centre more electron rich.
So practically, if we want to brominate benzene, we would treat