Iron-Salen Complexes for Hydroboration of Ketones: Enhancing Reactivity via Ligand Modulation at the Phenylene Bridge

Two iron salen complexes, Fe─di─F and Fe─di─Me, have been synthesized by incorporating substituents that possess distinct electronic properties to the phenyl diimine bridge of salen ligands, aiming to enhance the catalytic efficiency. These structural modifications enabled the di-fluoro substituted precatalyst, Fe─di─F, to exhibit a significant improvement in hydroboration of ketones. A diverse range of ketones were selectively hydroborated in the presence of various functional groups, even at minimal catalyst loading. The incorporation of fluorine atoms into the salen ligand proved to be a highly effective approach for boosting the catalytic efficiency of iron salen complexes in hydroboration reactions.