Nope. Companies can put a small portion of themselves in a foreign country, then say that that small portion is the most important part. I cannot cut off my big toe, mail it to the Cayman Islands, then say that I should be taxed under their laws instead as a result.

That analogous thing would be for a company to stop all business within a country, which is not being done.

They can't put a "small" portion of themselves in another country, that's why Pfizer was trying to buy Astra Zeneca. You need the merger of two relatively sized (by value) companies.

You know what you need to do that? It's in the tax law.

But can't a small portion of themselves be the most important part?

If it's saving them billions dollars a year - then that "small part" just might be your most important asset as a company.