JEE Main · 2023 · 10 Apr 2023 · Shift 2 · Hydrocarbons

With anhydrous $\mathrm{AlC}{\mathrm{l}}_3$ the side-chain $\mathrm{C}-\mathrm{Cl}$ ionises to a secondary carbocation at the carbon bearing the methyl group, which then attacks the ring intramolecularly in a Friedel-Crafts alkylation, closing a six-membered ring to give a tetralin. Ring closure occurs at the position para to the activating methoxy group and meta to the deactivating nitro group, which is also the less hindered site. The methyl group remains on the newly formed benzylic carbon, and the methoxy and nitro groups keep their mutual ortho relationship. The product is the methyl-substituted tetralin carrying the methoxy and nitro groups with the methyl on the benzylic carbon away from the methoxy group.