Synthesis and physicochemical evaluation of phosphorus(III) and phosphorus(V) substituted benzoxaboroles

This study presents a one-pot synthesis of phosphorus(III) benzoxaboroles using hypophosphorous acid to yield H-phosphinates. These H-phosphinates, together with their phosphonate congeners, were systematically evaluated for their physicochemical properties, including pK_a, diol-binding affinity, and oxidative stability in buffer. The presence of the phosphorus atom as either phosphorus(III) or phosphorus(V) provided high aqueous water solubility. The results demonstrated that the nature of the phosphorus substituent significantly influenced the acidity and binding behavior of the benzoxaborole core. Notably, the phosphorus(III) derivatives exhibited strong diol binding and exceptional oxidative resistance. Overall, this work introduces new H-phosphinyl and phosphoryl substituents to tune organoboron properties for use as sensors, therapeutics, or chemical probes.