One of nature’s most potent and versatile strategies for transformation of unactivated carbon centres involves activation of O₂ at an Fe(ii) cofactor to form an Fe(iv)-oxo (ferryl) intermediate that can either react as an electrophile or abstract a hydrogen atom (H˙) to initiate the installation of a diverse array of functional groups. A large and biologically important subset of enzymes that employ this strategy generate their key ferryl intermediates by coupling activation of O₂ at non-haem Fe(ii) cofactors to the oxidative decarboxylation of 2-oxoglutarate (2OG) to succinate and CO₂.^1–3...