I can't think any reason why you can't. Just remember magnolias need slightly acidic soil so you might have to make soil amendment with aluminum sulfate. You can get it at the garden center/hardware store. Be careful not to over do it though. If you have conifers grown nearby, the acidity should be fine and ready to go.

Check the ultimate height and width of the Magnolia when choosing the variety though as you won't be able to move if it gets too big.