${C_2}{H_5}I\,\xrightarrow{{Alc.\,KOH}}X\xrightarrow{{B{r_2}}}Y\xrightarrow{{KCN}}Z$
$[Figure]$ $\xrightarrow[{S_N2}]{{KOH}}$
$\begin{array}{*{20}{c}}
{C{H_3}}\\
{|\,\,\,\,\,}\\
{{C_6}{H_5}C{H_2} - C - C{H_2} - C{H_3}}\\
{|\,\,\,\,\,}\\
{Br\,\,\,}
\end{array}$ $\xrightarrow[{{C_2}{H_5}OH}]{{{C_2}{H_5}ONa}}$