Activating hot water recirculation pump in garage via extension cord under kitchen sink
Hi grant welcome to stackexchange. I don't what part of the world you are in but if you are in the US. No you can't do what you are suggesting. I haven't had time to figure out how many code violations are involved, but I will start with the fact that you cannot pass an extension cord through a wall or partition. So let's just say NEC Article 400 in particular 400.12 Uses not permitted pretty much covers why you can't or shouldn't do it.

You might want to bone up on this article before attempting any extension cord additions to your dwelling.

Good luck.