Capturing aqueous [18F]-fluoride with an arylboronic ester for PET: Synthesis and aqueous stability of a fluorescent [18F]-labeled aryltrifluoroborate

The aqueous stability of aryltrifluoroborates is of importance to their use in transition metal mediated coupling reactions as well as their potential use in [18F]-labeled aryltrifluoroborate PET imaging agents. Nevertheless, few studies have fully characterized the solvolysis of fluoride from an aryltrifluoroborate in water. Using [19F] NMR, fluorescence and [18F]-labeling techniques, we disclose the composition of an aryltrifluoroborate of exceptional kinetic stability with respect to solvolytic defluoridation. This work not only highlights the potential of using [18F]-labeled aryltrifluoroborates for PET tracers, but provides a chemical platform and a general approach for evaluating the stability of other aryltrifluoroborates.