Amine-Borane Complexes: Air-and Moisture-Stable Partners for Palladium-Catalyzed Borylation of Aryl Bromides and Chlorides

A method for using amine-borane complexes directly in palladium catalyzed borylation has been developed. The reaction proceeds through the sequential formation of a boronium species followed by deprotonation leading to the aminoborane. This reagent is then directly used in the borylation process leading, after work-up, to various boronic acid derivatives. The reaction was applied to (hetero)aryl triflates, iodides, bromides and chlorides.