${\left(C{H}_3\right)}_{2}CHBr\underset{\begin{array}{l}ii)CuI\\ iii){\left(C{H}_3\right)}_{2}CHC{H}_{2}Br\end{array}}{\overset{i)Li}{\to }}\left(A\right)$, This is Corey House method of synthesis of ‘A’ which