Boron Asymmetry in a BODIPY Derivative

A boradiazaindacene (BODIPY) fluorophore with a chirality held on the central boron has been synthesized and the racemate resolved. Dissymetrization of the BODIPY core was obtained by oxidation of the 3-methyl group to the corresponding carboxaldehyde. A hydrogen bond between the aldehyde proton and the fluorine on the boron atom was evidenced by both 1H NMR and X-ray diffraction. Chiral high-performance liquid chromatography as well as circular dichroism confirm the persistence of both enantiomers.