$\begin{matrix}
O\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \,\, \\
||\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
N\equiv C-C{{H}_{2}}-C-C{{H}_{2}}-CH=C{{H}_{2}}\to \\
\end{matrix}$ $\begin{matrix}
OH\,\,\,\,\,\,\,\,\, \\
|\,\,\,\,\,\,\,\,\, \,\,\,\, \\
N\equiv C-C{{H}_{2}}-\underset{H}{\mathop{C}}\,-C{{H}_{2}}-CH=C{{H}_{2}} \\
\end{matrix}$
$C{H_3}C{H_2}C{H_2}OH\,\xrightarrow{{PC{l_5}}}\,A\,\xrightarrow{{alc.\,\,KOH}}\,B$