Direct Decarboxylative Borylation

Decarboxylative borylation provides a powerful route for converting abundant aliphatic carboxylic acids to synthetically versatile alkyl boronates. However, existing radical approaches require substrate preactivation, typically as redox-active esters, which prevents their application in the decarboxylative borylation of free carboxylic acids. Herein, we report an iron ligand-to-metal charge-transfer (LMCT) photocatalytic strategy that enables the direct decarboxylative borylation of nonactivated carboxylic acids. By harnessing the photoinduced inner-sphere electron-transfer reactivity of iron carboxylate complexes, this strategy provides direct access to alkyl boronates from native carboxylic acids, including those embedded in structurally complex and industrially relevant molecules. The method exhibits reactivity orthogonal to established redox-active ester borylation strategies and provides a scalable route to valuable organoboron reagents from chemical feedstocks.