Hi mate, personally I wouldn't do that, although it would probably work initially. The hub is designed as your main power source, so it should be plugged into a stable mains supply, and then other equipment can be plugged/connected to it.
I understand what you're trying to achieve but, I think you would have fluctuation issues, and not worth the risk.
Recently on site, I saw a chap with a CTL 26 plugged into the mains, and he had a three way extension plugged into the CTM with, with a sander, jigsaw and circular saw plugged into the the three way, and was using the tools singularly, swapping the extractor hose each time a different tool was used.
I asked him if it was ok setting it up that way? he said he'd been doing that for a long time without problems. An electrician would be best to ask though.
I wouldn't plug the hub into the extractor though. It's designed for direct mains power.