Iron Photocatalysis Enabling Decarboxylative Bromination of (Hetero)Aryl Carboxylic Acids

A decarboxylative bromination protocol of (hetero)aryl carboxylic acids was achieved via iron photocatalysis. The photocatalytic decarboxylative functionalization of carboxylic acids was mostly limited to alkyl carboxylic acids. While several decarboxylative functionalization reactions of aryl carboxylic acids by copper photocatalysis have been disclosed in the last five years, the iron-catalyzed version is still rare. This work takes one step further to iron catalysis and uses NaBrO₃ as both the oxidant and the bromine source, with simple operation and readily available raw materials. A diverse range of (hetero)aryl carboxylic acids can undergo decarboxylative bromination through the iron catalyzed photocatalytic ligand-to-metal charge-transfer (LMCT) process, providing a feasible synthetic approach for multisubstituted bromoarenes.