Question #43978

Consider the following reaction sequence starting with 4-chlorobenzoic acid:

$\text{4-chlorobenzoic acid} \xrightarrow[\text{(ii) } H_2O]{\text{(i) } CH_3CH_2Cl \text{ (1 eq.), anhydrous } AlCl_3 \text{, } \Delta} \text{P}$

$\text{P} \xrightarrow{SOCl_2 \text{, Pyridine, reflux}} \text{Q}$

$\text{Q} \xrightarrow[\text{(ii) } H_2O]{\text{(i) Toluene (excess), anhydrous } AlCl_3 \text{, 298 K}} \text{R}$

$\text{R} \xrightarrow[\text{(ii) } H_3O^+]{\text{(i) } KMnO_4 \text{, } KOH \text{, } \Delta} \text{S}$

Identify the major organic product \textbf{S}.