MATLAB does not support all LaTeX libraries. I therefore find it easiest to create LaTeX expressions interactively in a live script using the interactive equation editor. On the INSERT tab, click Equation. This opens the EQUATION tab, from which you can select elements to add to you equation. Once complete, if I need the LaTeX I can right click on the equation and select "Copy as LaTeX".
Note there are options at the bottom of the menu to adjust the number of colums and rows (starts with a 2x2 grid).
Here is the copied LaTeX expression:
$\left\lbrace \begin{array}{l}
\mathrm{Line}\;1\;\mathrm{here}\\
\mathrm{Line}\;2\;\mathrm{here}\\
\mathrm{Line}\;3\;\mathrm{here}
\end{array}\right.$
I created this using the 'Cases' structure.