Well, my DD16 lived through this age with anxiety/perfectionism/low self-esteem-- and without ASD, though she has always had many spectrum-ey traits.
Our approach to discipline has always been much like Portia's. We are very strict with respect to behavioral CHOICES, and try to foster/coach emotional maturity and control. Still, I don't mind mentioning that the start of adolescence is pretty volatile for any child, and those with other confounding variables, well-- they may find it especially so.
DD found that retreat to low-sensory environments was a good way to manage. Many of my friends have used this approach with volatile children, regardless of LOG or diagnosis. No good can come of escalation in the moment-- for anyone, honestly.
Practice the statements that you would like to use to "cue" a behavioral time-out, and then sit down and rationally (when he's in the proper frame of mind, that is) lay out your behavioral contract, explaining that this is your job as a parent-- to help him learn to manage his behaviors so that he learns how to be functional as a teen and young adult. You can't throw tantrums at other people as a way to manage your frustrations. It just isn't done.
I could tell you what we did, but it's too idiosyncratic to be of use. We had a couple of "spots" in our home that were go-to "chill out" zones. We also developed a few "step down" exercises for use out and about-- though DD never really needed that in particular (again, idiosyncratic, probably).
"You cannot speak to me that way. You need to go to ______ until you are calmed down, please."
"You are acting as though you are two years old right now. If you really were two, I would put you down for a nap. I think that might still be a good idea-- go sit on your bed, please."
"Stairs. Sit. Now."
I also used to walk away SO THAT I WOULD NOT ENGAGE with her.
