$\begin{matrix}
Ph-C=CH-OH \\
|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
\,\,OH\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \\
\end{matrix}$ $\overset{Toutomerises}{\longleftrightarrow}$ $\begin{array}{*{20}{c}}
{O\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\\
{||\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\\
{Ph - C - C{H_2} - OH}
\end{array}$