para-Selective C-H Borylation of (Hetero)Arenes by Cooperative Iridium/Aluminum Catalysis

Abstract

para-Selective C-H borylation of benzamides and pyridines has been achieved by cooperative iridium/aluminum catalysis. A combination of iridium catalysts commonly employed for arene C-H borylation and bulky aluminum-based Lewis acid catalysts provides an unprecedented strategy for controlling the regioselectivity of C-H borylation to give variously substituted (hetero)arylboronates, which are versatile synthetic intermediates for complex multi-substituted aromatic compounds.

Keywords: C-H activation; Lewis acids; boronate esters; iridium; regioselectivity.