RotateAround - opening a door in 2D

If I have a door (in 2D) and I want to swing it open inwards., How would i do this in a 2D game? Is RotateAround the way to go?

I have tried all kinds of variations of RotateAround with no luck. I assume I would want to rotate around the Y axis from 0-90 degrees? My axis I set to be the very right middle of the door. I am not sure what point should be.

Vector3 point = new Vector3(0,1,0); Vector3 axis = new Vector3(doorAxisX, doorAxisY, 0);

Door.transform.RotateAround(point, axis, 50 * Time.deltaTime);

Any ideas how to make this work?

Thanks in advance. --Mike