Diazaborines Resist H2O2-Mediated Oxidation But React Rapidly with Peroxynitrite in Aqueous Buffer

Arylboronic acids oxidize with H2O2 and peroxynitrite (ONOO-) to yield their corresponding phenols. However, simple arylboronic acids struggle to discriminate between these two biological reactive oxygen species (ROS). Here, we show that diazaborines (DABs) react slowly with H2O2 but rapidly with peroxynitrite in aqueous buffer. Moreover, oxidation of DABs with H2O2 and ONOO- first yields a long-lived intermediate that ultimately converts to the phenol. Taken together, our work shows that diazaborines exhibit enhanced kinetic discrimination between H2O2 and ONOO-, opening up new opportunities for diazaborine-based tools in chemical biology.