Asymmetric Palladium Migration for Synthesis of Chiral-at-Cage o-Carboranes

Metal migration strategy can offer BH functionalization of o-carboranes at different positions from where initial bond activation occurs to achieve bifunctionalized o-carboranes in one reaction. We report in this article an enantioselective 3,4-bifunctionalization of o-carboranes via asymmetric Pd migration with a high efficiency and up to 98 % ee. This asymmetric catalysis has a broad substrates scope, leading to the preparation of a class of chiral-at-cage o-carborane derivatives. The enantiocontrol model is suggested on the basis of density functional theory (DFT) results, where the chiral Trost ligand plays a crucial role in this enantioselective Pd migration from exo-alkenyl sp² C to the cage B(4) position of o-carborane.