Terrible Two's , oh so terrible

Do they really turn into terrible three's.

whenever my son needed to be disciplined we would put him in time out, all we had to do was point to the chair and he would go run and sit in it and he wouldn't get up until I told him he could. Now it just doesn't work that way anymore. I have to go put him in it and he will keep getting up and then I end up having to stand there and make him and he still will try to get up. spanking doesn't help either, he will just go back to doing what he was doing. I take away toys, turn his shows off, everything and nothing seems to work anymore. I have raised my voice, and I have tried simply just trying to talk in a rational pleasant voice. I even tried rewarding him for good behavior but that doesn't work either. The only time he seems to listen to me anymore when I tell him to do something, is if I say okay clean up your toys and we will have popcorn or go outside to play and he wants to do that then he will do what I ask. Any suggestions, I don't want to have to give him something everytime to make him do something.