Does it feel more like disrespect? Or defiance?
Are your requests disrespectful to him? If you want him to put his plate in the sink, are you asking in a respectful way? Or using a sing-songy voice? Or in a demanding tone? "I need you to put your plate in the sink please... thank you". Then, expect that he will. If he doesn't, leave it there, and serve his next meal off of that same plate. If he wants a clean plate, he'll need to put his dirty plate in the sink and get himself a clean plate. (maybe leave one on the counter for him)
I only ask the kids once. (if I know they heard me...it's unfair to make a request when the child is busy, and expect them to have comprehended it) Anyway.. I ask once. "Lets get in the car". If they don't get in the car, we don't go. I sit back down, turn on the TV, and we don't go. (you have to manipulate this... you can't pull this on a school day, pick something reasonably fun, but unimportant) Or if Dad is home, You go, and leave him home. "Well, Mommy needed you to get in the car, but you didn't... sorry, maybe next time".
One of the reasons he behaves well at school is that they are firm, yet patient. They say what they want done, and expect it to be done. If it's not done, it's the student's problem, not the teacher's problem. If you can find a way to make him responsible for his own behavior like they do in school, you might see a change.
But, don't use baby talk, don't end ANY request with "O.K?" If it sounds weak or optional, then it is optional.
Don't make requests or say "no" when it's not that important. If you are constantly asking for something of him, he will stop listening. My husband does this to me.... I can be busy with four things, and he will say "Can you look online for that number I need?" Then, he will stand there and wait. So, I need to stop everything to go do the thing that JUST popped into his head. It's beyond irritating.
Other people here do not like this book, but I love the one I have. "Love and Logic". You can't read it and take ALL of it seriously. It's like any form of discipline, you take only what works for you and leave the rest. It's best to read several different books and form your own mix of the books you like.