Reactivity Features of ortho-Carboranillithium towards 3,6-Diaryl-1,2,4,5-tetrazines

The reaction of ortho-carboranilithium with 3,6-di(2-pyridyl)-1,2,4,5-tetrazine, considered as an example of the “from challenging to simple” strategy in the chemistry of carboranes, leads to the previously unknown 3-ortho-carboranyl-[1,2,3]triazolo[1,5-a]pyridine as a result of cleavage of the tetrazine cycle and subsequent formation of the triazole cycle with nitrogen elimination. The structure of the obtained compound was confirmed by the spectroscopic and X-ray diffraction studies. The reaction mechanism, which was additionally confirmed by quantum-chemical calculations of electron densities and the Fukui function, was proposed.