Unexpected synthesis of 4,4'-bis(1,2,3-triazole)s from calcium carbide as an acetylene source via a click reaction

4,4'-Bis(1,2,3-triazole)s were efficiently constructed in one step at room temperature through a click reaction, utilizing calcium carbide as the alkyne source, sodium azide as the nitrogen source, and benzyl halides as the substrate, with simultaneous formation of two C-N bonds and one C-C bond. This protocol has the advantages of an easily handled, cost effective alkyne source, simple and efficient synthesis steps, a wide substrate range, satisfactory yields and good selectivity. Moreover, this atomically efficient reaction involving two calcium carbide molecules is expected to greatly increase the utilization of calcium carbide, and the method can be scaled up to the gram scale.