Valve leaking under kitchen sink. Attached to copper with compression valve. When I try to remove it just spins in circle. Can I get it off without cutting it? (There isn't much pipe sticking out of the wall).

There is a special tool to remove the ring.

Valve leaking under kitchen sink. Attached to copper with compression valve. When I try to remove it just spins in circle. Can I get it off without cutting it? (There isn't much pipe sticking out of the wall).

You remove that angle stop, (see image) by holding the valve body with one wrench and backing off the large nut counterclockwixe. That stops the spin and allows the valve to be removed. If you'rereplacing the angle stop you won't need to remove the compression nut and ferrule, simply reuse them.
However, If you wish to remove the nut and ferrule here's the tool KISS spoke of. This tool is a combination handle and ferrule puller. Good luck, Tom

Thank you for your info. Very helpful. I tried reusing the nut & ring but it leaked so just cut the pipe and put new valve. Had just enough to get it on there-next person will have to extend it, I guess. Didn't know about the special tool and had already sawed it off. Will definitely get one for next time.

We're just glad you're fixed up. If you need more help simply click on back, Tom