Iridium(III)-Catalyzed Regioselective B(4)-H Allenylation of o -Carboranes by Ball Milling.

We disclose an iridium(III)-catalyzed regioselective B(4)-H allenylation of o -carboranes from o -carborane acids and propargyl carbonates under ball-milling conditions. This study sheds light on a novel method to accomplish regioselective B(4)-allenylation of o -carborane that cannot be realized through conventional solution-based reactions. Control experiments, including solution, neat, microwave, and high-temperature reactions, reveal that the B(4)-H allenylation of o -carborane is unique for ball-milling conditions.