2 minutes doesn't sound unreasonable to me. Get your setup done, use a stand in and be 100% ready by the time you ask for them to step in. I realize it depends on exactly what kind of photo you're generating (environmental might take more time), but 2 minutes should be sufficient to get a reasonable posture and expression.
I think it's good that you asked for the time and got it, but I'm not sure I see how the CEO was being rude.
Just rude. I had an assignment to photograph a CEO, upon my arrival in a rude obnoxious way, he told me in no uncertain terms, I had 2-minutes to make the photograph because he was very busy. I said perhaps then we should reschedule at a better time, because I would not be able to do the photographs well or to what was expected of me in 2-minutes. He then said well, how long do you need and I said I can be out in 15 minutes, to which he agreed.