Base-Promoted Decarboxylative Azo-Coupling: Construction of Unsymmetrical Azocarboranes.

Base-promoted decarboxylative azo couplings of carboranyl carboxylic acids with diazo salts have been developed to provide trans-azocarboranes in high yields (up to 94%). This approach is simple, efficient, and compatible with various functional groups. Mechanistically, the coupling has been proven to proceed in a nonradical pathway, which is distinct from those classical decarboxylative couplings.