$' A ^{\prime} \stackrel{ HNO _3}{\longrightarrow} X ^{\prime} \stackrel{ NaBH _4}{\longrightarrow} \underset{\text { Chiral compound }}{\text { } B ^{}}$
$\begin{array}{*{20}{c}}
{R = - CH - Cl}\\
{|\,\,}\\
{\,\,\,\,C{H_3}}
\end{array}\,\,\,\,,\,\,\,\,\,\,\,\,\,\,\begin{array}{*{20}{c}}
{S = - CH - Cl}\\
{|\,\,}\\
{Br}
\end{array}$