Copper-Catalyzed C(sp)-H Bond Hydrazidation.

A catalytic, direct synthetic strategy for preparing ynehydrazides with terminal alkynes and dialkyl azodicarboxylates is described. The protocol utilizes a cheap copper catalyst in combination with a catalytic amount of a weak base. The high sustainability, good practicality, broad substrate scope, and wide functional group tolerance comprised the advantages of this reaction. Synthetic applications and preliminary mechanistic studies have been conducted.