Heterocyclization of enediynes promoted by sodium azide: a case of ambiguity of X-ray data and structure revision.

It has been shown that contrary to the literature data the tandem cyclization of (Z)-1-aryl-3-hexen-1,5-diynes promoted by sodium azide results in the formation of the corresponding [1,2,3]triazolo[1,5-a]pyridines, not 1H-benzotriazole derivatives. Apparently, incorrect structure elucidation made by previous investigators originates from misinterpretation of X-ray data. A number of new transformations of this type as well as X-ray and NMR experiments are discussed.