The moon's synchronous rotation has a lot to do with what's called tidal locking. Besides our own moon, the other moons that orbit other planets in our own solar system are affected by this. It has to do with one face or side of our moon for example always facing the earth. The earths gravitational pull locks that side of the moon in place if you will. So In the moons case, it is the side with all of the maria, or dark areas called the seas of the moon. Which are volcanic deposits laid across the moon eons ago. Hopefully this is somewhat of an answer or explanation you were looking for.