Synthesis, characterization and electrochemical properties of 3-ferrocenylbenzoxaboroles

3-Ferrocenylbenzoxaboroles are organoboron compounds combining the structural features of diol-binding benzoxaborole with redox-active ferrocene. Herein, a two-step method for the preparation of these hitherto unreported compounds is described. First, ferrocenecarboxaldehyde is transformed into 2-halo-1-ferrocenylbenzyl alcohols via halogen-selective transmetallation. Next, the obtained alcohols are subjected to palladium-catalyzed borylation, affording the title benzoxaboroles. All compounds have been characterized spectroscopically by means of NMR and FTIR, and their purity confirmed by elemental analysis. Cyclic voltammetry studies have allowed for the determination of the redox potentials, diffusion coefficients and electron-transfer rate constants of the studied electroactive species.