JEE Advanced 2021 · Paper 2, Chemistry question 1

Follow each sequence.

• (A) o-Toluidine is diazotised, CuCN gives o-tolunitrile, DIBAL-H gives o-tolualdehyde, and Wolff-Kishner reduction turns the CHO into $\ce{CH3}$. Product: o-xylene.
• (B) 2-Bromotoluene forms a Grignard reagent, which with $\ce{CO2}$ gives o-toluic acid. $\ce{SOCl2}$ gives the acid chloride, Rosenmund reduction ($\ce{H2}$, Pd-$\ce{BaSO4}$) gives the aldehyde, and Clemmensen reduction gives $\ce{CH3}$. Product: o-xylene.
• (C) Hydroboration-oxidation of 2-methylstyrene gives $\ce{ArCH2CH2OH}$. $\ce{PBr3}$ then Zn/HCl gives $\ce{ArCH2CH3}$. Product: 2-ethyltoluene, not o-xylene.
• (D) Ozonolysis of indene gives $\ce{OHC-C6H4-CH2CHO}$. Wolff-Kishner reduction then gives 2-ethyltoluene, not o-xylene.

(A), (B)