Iron-catalyzed decarbonylative borylation enables the one-pot diversification of (Hetero)Aryl and alkyl carboxylic acids

Carboxylic acids are cheap, abundant, and environmentally friendly and are widely employed as partners in cross-coupling reactions. Transition-metal-catalyzed carboxylic acid transformations are typically achieved at extreme temperatures (usually >150°C), significantly limiting their practicality. Here, iron-catalyzed decarbonylation of aryl and alkyl carboxylic acids has been developed, providing the corresponding borylated products with good efficiency. This protocol features excellent functional group compatibility, mild conditions, and the late-stage borylation of bio-relevant carboxylic acids, thus offering excellent opportunities for applications in medicinal chemistry and organic synthesis. Preliminary mechanistic studies suggest that the iron(I)-boryl species may be the crucial intermediate and that a decarbonylative process is involved in this catalytic transformation.