Not Minding!

My son is a lil over 2 1/2. He's always been a mommy's baby. But in the last few months I've realized that he almost refuses to mind. He does things that he's not supposed to deliberately. I've tried timeouts, appropriate spankings for his age, and talking to him. Nothing seems to work. If there's anyone out there that's gone through this with their children please let me know. I just want to eliminate the issue and move forward. How did you get yours out of this?