Pd‐Catalyzed Selective Bifunctionalization of 3‐Iodo‐o‐Carborane by Pd Migration

A palladium‐catalyzed highly selective 3,4‐bifunctionalization of 3‐I‐o‐carborane has been developed, leading to the preparation of 3‐alkenyl‐4‐R‐o‐carboranes (R=alkyl, alkynyl, aryl, allyl, CN, and amido) in high to excellent yields. This protocol combines the sequential activation of cage B(3)−I and B(4)−H bonds by Pd migration from exo‐alkenyl sp2 C to cage B(4), which is driven by thermodynamic force. This represents a brand‐new strategy for selective bifunctionalization of carboranes with two different substituents. A highly regioselective sequential activation of cage B−I and B−H bonds in o‐carborane has been achieved in a one‐pot manner. The thermodynamically favorable migration of Pd from exo‐alkenyl sp2 carbon to cage B(4) serves as a key step in this new process, which represents a new route for regioselective bifunctionalization of o‐carborane with different substituents.