Final answer:
Electron-withdrawing groups withdraw electrons from aromatic rings through the inductive effect, increasing the ring's susceptibility to nucleophilic attack, thereby facilitating nucleophilic aromatic substitution reactions.
Step-by-step explanation:
Electron-withdrawing groups (EWGs) affect the electronics of aromatic rings through the inductive effect, pulling electron density away from the ring. This occurs because EWGs are more electronegative than the carbon atoms of the aromatic ring and can stabilize a negative charge through resonance in structures like nitro groups and carbonyl moieties. This electron-withdrawing ability facilitates certain reactions, like nucleophilic aromatic substitution, where an electron-poor aromatic ring is more susceptible to attack by a nucleophile, contrasting with electrophilic aromatic substitution, where an electron-rich ring is targeted by electrophiles.
In both types of substitution reactions, the stability of the aromatic ring plays a crucial role. In electrophilic aromatic substitutions, the ring forms an unstable intermediate that quickly sheds a proton to regain aromatic stability. Similarly, in nucleophilic aromatic substitutions, the presence of a strong electron-withdrawing group and a good leaving group are necessary to favor the reaction.