B–N, B–O, and B–CN Bond Formation via Palladium-Catalyzed Cross-Coupling of B‑Bromo-Carboranes

Carboranes
are boron-rich molecules that can be functionalized
through metal-catalyzed cross-coupling. Here, for the first time,
we report the use of bromo-carboranes in palladium-catalyzed cross-coupling
for efficient B–N, B–O, and unprecedented B–CN
bond formation. In many cases bromo-carboranes outperform the traditionally
utilized iodo-carborane species. This marked difference in reactivity
is leveraged to circumvent multistep functionalization by directly
coupling small nucleophiles (-OH, -NH2, and -CN) and multiple
functional groups onto the boron-rich clusters.