Boron breaks C–H bonds without metal

Abstract

Creating new carbon-carbon bonds is the backbone of synthesizing drugs and natural products. Ultimately, many chemists do this through a Suzuki coupling reaction, which marries an organohalide to an organoboron to beget the desired C–C bond. Now, two independent groups have come up with a simpler way to insert the necessary B atoms, an advance that could make it easier to make organoboron compounds (Angew. Chem., Int. Ed. 2019, DOI:10.1002/anie.201909786 and Nature 2019, DOI: 10.1038/s41586-019-1640-2). Both groups used indoles, bicyclic compounds made up of a benzene ring fused to a pyrrole ring, to figure out their new coupling reactions. Indoles are important precursors to many biomolecules and drugs, and their chemistry is well understood. Chemists know how to get a boron atom onto the pyrrole’s C-2 and C-3 positions of an indole, but they have had a harder time cracking the benzyl backbone. “Reactivity in the pyrrolic unit has lower