A direct B(4)–H monoacyloxylation via a Pd-catalyzed regioselective B(4)–H activation of o-carborane acids with phenyliodonium dicarboxylates was developed, and a series of B(4)–H monoacyloxylated o-carboranes decorated with active groups were synthesized with moderate to good yields as well as excellent selectivity. In addition, a direct B­(4,5)–H diacetoxylation from o-carborane acids with phenyliodonium diacetate was demonstrated.

Transition-metal-free synthetic method for o-carborane-fused pyrazoles as a new scaffold has been developed from the reaction of B(4)-acylmethyl or B­(3,5)-diacylmethyl o-carborane with 2-azido-1,3-dimethyl­imidazolinium hexafluorophosphate (ADMP) in the presence of DBU in acetonitrile through sequential diazotization and cyclization reaction in one pot, consequently allowing twofold C–N bond formation under extremely mild conditions and high functional group tolerance.

A ruthenium‐catalyzed selective B4 amidation of o‐carboranes with a variety of alkyl‐, aryl‐, and heteroaryl‐substituted dioxazolones is developed by carboxylic acid‐assisted B(4)‐H bond activation in o‐carborane acids, affording a multitude of (4)‐amidated o‐carboranes in good yields with the evolution of carbon dioxide. In addition, the two‐fold selective decarboxylative amidation reaction of the cage B(4)‐H bond in o‐carborane was accomplished.