Systematic Evaluation of Halogen Substitution in ortho-Benzoxy Phenylboronic Acid Catalysts for Amidation Reactions

Boronic acids have emerged as powerful catalysts for amidation reactions. Based on a previously identified orthobenzoxy phenylboronic acid motif, a systematic structure-activity study was performed. A catalyst library spanning F, Cl, Br, and I substitution on the ortho-benzoxy substituent was synthesized and evaluated as catalysts in amidation reactions. Catalytic activity increased in the order F < Cl < Br < I and followed the substitution pattern ortho < para < meta, with the meta-iodo derivative showing the highest conversion. This systematic comparison established structure-activity relationships within the catalyst library and provides a basis for the design of more efficient amidation catalysts