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

Abstract

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. • Iron-catalyzed decarbonylative borylation under mild conditions • The generation of low-valent iron species in the iron/borane/alkoxide systems • Iron(I) species may be the crucial intermediate • The involvement of decarbonylative process The transition-metal-catalyzed transformation of carboxylic acids is of great significance. Wen et al. developed an iron-catalyzed decarbonylation of aryl and alkyl carboxylic acids under relatively mild conditions (90°C–130°C), delivering the corresponding borylated products with good efficiency.