When naphthalene undergoes an irreversible electrophilic aromatic substitution, the major product is the kinetic product, which proceeds through the most stable arenium ion intermediate. With this in mind, draw the curved arrow mechanism for the first step of the electrophilic aromatic substitution of naphthalene with the acylium ion generated from acetyl chloride and AlCl3. Then draw the curved arrows and a resonance structure in step 2 with an unbroken benzenoid ring. Draw all atoms, electrons, and charges, if necessary, on all structures; draw curved arrows on all structures except the last one. Do not draw any inorganic byproducts or counterions.

In the first part of the problem, we have the electrophilic aromatic substitution (Friedel-crafts reaction) in naphthalene. The first step is the production of the acylium ion by the reaction of acetyl chloride and [tex]AlCl_3[/tex]. Then a double bond attacks the acylium ion to form a new C-C bond. Finally, a hydrogen atom is eliminated and the aromaticity is regenerated in the molecule. (See figure 1)

In the second part of the question, we have to draw the resonance structures in this reaction when benzene is added instead of naphthalene. Where a positive charge is produced in the alpha carbon on the ring. This positive charge, can be moved inside the ring if we move the double bonds and we will have cations on the ortho and para positions. (See figure 2).