Abstract:
Let $G$ be a finite simple group with Sylow 2-subgroup $T$. If there is an extra-special sub-group of index 2 in $T$, then $G$ is isomorphic to one of the following groups:
$$ \begin{array}{llllll}
A_8,&A_9,&M_{11},&M_{12}\\
L_2(q),&L_3(q),&U_3(q),&G_2(q),&D_4^2(q),&PSp_4(q)
\end{array} $$
for an appropriate odd $q$.