Reactivity and Orientation of Pyrrole, Furan, Thiophene

Pyrrole, Thiophene and Furan give electrophilic aromatic substitution reactions. These Compounds are more reactive compared to Benzene. Electrophiles majorly attack the 2nd position rather than the 3rd position in these heterocyclic compounds. The reason behind it is the more number of the resonating intermediate structure are possible to accommodate the positive charge when electrophile attacks on 2nd position (Three resonating intermediate structure) That makes the intermediate carbocation more stable while if electrophile attacks on the 3rd position then only two resonating intermediate structures are possible as shown in the figure which is comparatively less stable. That's why the attack of electrophiles takes place at the 2nd position in Pyrrole, Furan, Thiophene.