Palladium-Catalyzed Direct Dialkenylation of Cage BH Bonds in o-Carboranes through Cross-Coupling Reactions

Palladium‐catalyzed direct dialkenylation of cage B(4,5)H bonds in o‐carboranes has been achieved with the help of a carboxylic acid directing group, leading to the preparation of a series of 4,5‐[trans‐(ArCHCH)]2‐ocarboranes in high yields with excellent regioselectivity. The traceless directing group, eliminated during the course of the reaction, is responsible for controlling regioselectivity and dialkenylation. A possible catalytic cycle is proposed, involving a tandem sequence of PdII‐initiated cage BH activation, alkene insertion, β‐H elimination, reductive elimination, and decarboxylation. Giving directions: Pd‐catalyzed direct dialkenylation of cage B(4,5)H bonds in o‐carboranes has been achieved using a carboxylic acid directing group, leading to the preparation of a series of 4,5‐[trans‐(ArCHCH)]2‐o‐carboranes in high yields and with excellent regioselectivity.