Treatment of benzene with $\mathrm{CO} / \mathrm{HCl}$ in the presence of anhydrous $\mathrm{AlCl}_3 / \mathrm{CuCl}$ followed by reaction with $\mathrm{Ac}_2 \mathrm{O} / \mathrm{NaOAc}$ gives compound $\mathbf{X}$ as the major product. Compound $\mathbf{X}$ upon reaction with $\mathrm{Br}_2 / \mathrm{Na}_2 \mathrm{CO}_3$, followed by heating at 473 K with moist KOH furnishes $\mathbf{Y}$ as the major product. Reaction of $\mathbf{X}$ with $\mathrm{H}_2 / \mathrm{Pd}-\mathrm{C}$, followed by $\mathrm{H}_3 \mathrm{PO}_4$ treatment gives $\mathbf{Z}$ as the major product.
The compound Y is