Using a Set Curriculum

I don't use a set curriculum, except for math. And he loved math, was exceptional at it, until I started using this curriculum in November, then he hated it! But he has gotten used to it, I really had to set a schedule for that, one day a week for 20 minutes. But heaven forbid if I try to go beyond that time limit, he watches the clock like a hawk. I try to follow his interests, but even if I find something I know he would love, he resists me. I do try to discipline him when he starts with a bad attitude, usually sending him to his room to think about the situation and he can come down when he is ready. But I make sure he knows he still has to finish the schoolwork when he returns.