Protection of Boronic Acids Using a Tridentate Aminophenol ONO Ligand for Selective Suzuki-Miyaura Coupling

Boronic acid protecting group chemistry powerfully enhances the versatility of Suzuki-Miyaura cross-coupling. Prominent examples include trifluoroborate salts, N-methyliminodiacetic acid (MIDA) boronates, and 1,8-diaminonaphthalene boronamides. In this work, we present a bis(2-hydroxybenzyl)methylamine (BOMA) ligand that forms tridentate complexes with boronic acids much like the MIDA ligand but the deprotection is facilitated by organic acids. The BOMA boronates showed considerable stability in both aqueous base and acid, and a variety of chemoselective reactions were performed on these boronates, including selective Suzuki-Miyaura coupling, palladium-catalyzed borylation, ester hydrolysis, alkylation, lithiation-borylation, and oxidative hydroxydeboronation.

Automated summary

Boronic acid protecting group chemistry significantly expands the versatility of Suzuki-Miyaura cross-coupling. The BOMA ligand, similar to the MIDA ligand, forms tridentate complexes with boronic acids, but can be deprotected using organic acids. BOMA boronates exhibit excellent stability in both alkaline and acidic conditions, enabling a wide range of chemoselective reactions.