Classic/killer/easy application for the deuterium kinetic isotope effect?

I'm a physicist. While visiting someone's o-chem class I learned about the existence of the deuterium kinetic isotope effect. This seems like an extremely sweet example of zero-point energy, and I would like to use it as an example when teaching the basic quantum mechanics that we teach in freshman physics at a community college.


In this context, I would like to be able to give a good example where we actually care about the deuterium kinetic isotope effect. Ideally this would be an example that would be at least somewhat understandable to people who (like me) have no clue about organic chemistry. Something like:


* Without the deuterium kinetic isotope effect, we wouldn't be able to synthesize x (where x is nail polish, fullerenes, methamphetamine, ...)
* Historically, there was intense controversy about how this mysterious chemical process in x worked (where x is learning in slime molds, work-hardening of bronze, ...), but then they injected their (slime mold, ...) with deuterium and used the deuterium kinetic isotope effect to prove that ...


Related: [Why is a C–D bond stronger than a C–H bond?](https://chemistry.stackexchange.com/questions/70128/why-is-a-c-d-bond-stronger-than-a-c-h-bond)


