$\begin{array}{*{20}{c}}
{\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,C{H_3}} \\
|
\end{array}} \\
{C{H_3} - C - C{H_3}} \\
| \\
H
\end{array}{\mkern 1mu} $ $\mathop {\xrightarrow{{C{H_3}OBr}}}\limits_{C{H_3}OH} $
$Ph - C \equiv C - Ph \to $