Hydrogen Peroxide-Responsive Triggers Based on Borinic Acids: Molecular Insights into the Control of Oxidative Rearrangement.

Arylborinic acids represent new, efficient, and underexplored hydrogen peroxide-responsive triggers. In contrast to boronic acids, two concomitant oxidative rearrangements are involved in the complete oxidation of these species, which might represent a major limitation for an efficient effector (drug or fluorophore) release. Herein, a comprehensive study of H 2 O 2 -mediated unsymmetrical arylborinic acid oxidation to investigate the factors that could selectively guide their oxidative rearrangement is described. The o-CF 3 substituent was found to be an excellent directing group allowing a complete regioselectivity on borinic acid models. This result was successfully applied to synthesizing new borinic acid-based fluorogenic probes, which exclusively release the fluorescent moiety upon H 2 O 2 treatment. These compounds maintained their superior kinetic properties compared to boronic acids, thus further enhancing the potential of arylborinic acids as valuable new H 2 O 2 -sensitive triggers.