Each time he does it, calmly tell him no. If he persists, put him in
another room for 5 to 10 minutes. Let him out and try again.
Rinse. Repeat. Wipe hands on pants. *LOL*

He'll get the picture eventually. This will require a good deal of
patience and consistency on your part.

Also, if you work for hours and he has no playmate, he's probably bored
out of his little mind. Bored cats are bratty cats. They want attention.
You didn't say what toys, if any, you have for him. I recommend a large
cat tree if you can, with dangly toys, catnip, and a little tunnel to
hide in. By the window is a bonus. Animated mousey toys can be great
fun, too.

Reward him if he leaves you alone for longer than he usually does. Stop
what you're doing and play with him for a few minutes. Increase the time
required for reward. Say he normally starts bothering you after 5
minutes. If he waits 7 minutes, reward him. Keep that up until he always
waits at least 7 minutes, then go to 10. And so on.

It's going to take some time, of course.