Palladium‐Catalyzed Cascade Deboronation/Regioselective B−P Coupling of closo‐Carboranes

Abstract A cascade deboronation/regioselective B−P coupling of closo ‐carboranes is disclosed using a combination of palladium catalysts and nitrogen or phosphine‐containing directing groups. Unsymmetric C‐substituted closo ‐carboranes, including C‐monosubstituted and unsymmetric 1,2‐disubstituted closo ‐carboranes, are tolerated. Select closo ‐carboranes bearing other directing groups, such as benzoxazole, and diphenylphosphine, are compatible substrates for this reaction. Phosphine and arsenic can be utilized as effective coupling partners. Furthermore, a catalytic amount of palladium salt mediates the regioselective B−H activation process. Readily available closo ‐carboranes as the starting materials for direct one‐pot synthesis of functionalized nido ‐carboranes and the in‐situ formation of nido ‐carborane intermediates without purification are important features in terms of practical applications.