Paragraph: The reaction of compound $\mathbf{P}$ with $\mathrm{CH}_{3} \mathrm{MgBr}$ (excess) in…

Paragraph: The reaction of compound $\mathbf{P}$ with $\mathrm{CH}_{3} \mathrm{MgBr}$ (excess) in $\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{O}$ followed by addition of $\mathrm{H}_{2} \mathrm{O}$ gives $\mathbf{Q}$. The compound $\mathbf{Q}$ on treatment with $\mathrm{H}_{2} \mathrm{SO}_{4}$ at $0^{\circ} \mathrm{C}$ gives $\mathbf{R}$. The reaction of $\mathbf{R}$ with $\mathrm{CH}_{3} \mathrm{COCl}$ in the presence of anhydrous $\mathrm{AlCl}_{3}$ in $\mathrm{CH}_{2} \mathrm{Cl}_{2}$ followed by treatment with $\mathrm{H}_{2} \mathrm{O}$ produces compound $\mathbf{S}$. [Et in compound $\mathbf{P}$ is ethyl group]

Question: The reactions, $\mathbf{Q}$ to $\mathbf{R}$ and $\mathbf{R}$ to $\mathbf{S}$, are

1. Dehydration and Friedel-Crafts acylation
2. Friedel-Crafts alkylation, dehydration, and Friedel-Crafts acylation
3. Aromatic sulfonation and Friedel-Crafts acylation
4. Friedel-Crafts alkylation and Friedel-Crafts acylation

Solution

The reaction of an ester (other than format) with Grignard’s reagent followed by hydrolysis in acidic medium produces a tertiary alcohol. The dehydration of $3^{\mathrm{o}}$-alcohol at ${\text{O}}^{\text{o}}\text{C}$ in the given compound produces an alkyl group in the benzene ring. This compound on reaction with ${\text{CH}}_{\text{3}}{\text{COCl}}_{\text{2}}$ in ${\text{CH}}_2{\text{Cl}}_{\text{2}}$ and shows Friedel craft's alkylation reaction

Asked in: JEE Advanced 2017 (Paper 2)

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