I have been updating my page on patentability / non-obviousness of chiral compounds. While working on it, I read about a new molecule ─ a chiral triaryloxonium ion ─ in Chemical & Engineering News (C&EN). Astoundingly, the stereocenter is the oxygen, rather than a carbon, the atom most famous for its chiral capabilities. Chemists synthesized the first stable molecule whose chirality is solely attributed to a stereogenic oxygen. They published their work in Nature. See, O. Smith et al., Control of Stereogenic Oxygen in a Helically Chiral Oxonium Ion, Nature, 615, 430–435 (2023). 

Link to C&EN article: This New Molecule Owes its Chirality to Oxygen Alone

Can someone patent a chiral oxonium ion?

We do not know if the chemists filed a patent application claiming the composition. But that didn’t stop me from speculating as to such a possibility. I think that a patent application claiming a chiral oxygen would be robust. Firstly, the inventors reduced the molecule to practice. They physically made it. It surely is not an abstract idea. Secondly, if the molecule is truly the first stable molecule, then novelty should be no problem. Thirdly, I think that such a compound is non-obvious and inventive.

Might a chiral oxygen be obvious?

Let’s focus on non-obviousness. Might a chiral oxonium ion be obvious? I think that, most likely, a chiral oxonium ion would not be obvious. As noted on Organic Patent’s page, Obviousness of Stereoisomers & Purified Compounds, critical support for arguing non-obviousness includes evidence of unexpected properties and difficulties associated with resolving compounds. Other secondary considerations / “Graham” factors are super helpful too, such as long felt but unsolved needs. The articles cited above have an abundance of such evidence.

Below are a few powerful quotes:

• “Oxygen has been less cooperative.”
• “Oxonium ions … have the potential to be chiral, but they are notoriously reactive”
• “The few previous examples of chiral oxonium ions are too unstable to be isolated … so the search for chiral oxonium ions languished in the literature”