Aromaticity and Electrophilic Substitution An aromatic compound is a hydrocarbon or organic compound that exhibits cyclic structure. Aromatic compounds typi...
Aromaticity and Electrophilic Substitution
An aromatic compound is a hydrocarbon or organic compound that exhibits cyclic structure. Aromatic compounds typically exhibit a conjugated pi system, which consists of delocalized electrons that extend the molecular ring. This conjugated pi system can participate in electrophilic substitution reactions.
Electrophilic substitution is a chemical reaction in which an electrophile (a species that has a partial positive charge) attacks an electrophile site (a species with a partial negative charge). This reaction can occur when an electrophile attacks an electrophile site on an aromatic ring, or when an electrophile attacks an electrophile site on a molecule that contains an aromatic ring.
In aromatic electrophilic substitution reactions, the aromatic ring acts as the nucleophile, and the electrophile attacks an electrophilic site on the ring. This reaction can proceed via a concerted mechanism, in which the electrophile attacks the aromatic ring simultaneously with the loss of a proton. Alternatively, this reaction can proceed via an unimolecular mechanism, in which the electrophile attacks the aromatic ring sequentially.
An example of aromatic electrophilic substitution is the reaction between hydrogen bromide and benzene. In this reaction, the hydrogen bromide ion attacks an electrophilic site on the benzene ring, leading to the formation of the product, phenol