Palladium‐Catalyzed Carbonylative Annulation of 1‐Hydroxy‐o‐Carborane and Internal Alkynes via Regioselective B‐H Activation

Abstract A Pd‐catalyzed three‐component carbonylative‐annulation of 1‐hydroxy‐ o ‐carborane, internal alkyne and carbon monoxide has been achieved via direct and regioselective cage B−H activation. A class of C,B‐substituted carborano‐coumarin derivatives with potential applications in pharmaceuticals were facilely prepared in moderate to high yields with excellent chemoselectivity and regioselectivity. A plausible reaction mechanism including CO insertion, electrophilic B−H metalation, alkyne insertion and reductive elimination was proposed.