Copper-Catalyzed Alkynylation of Hydrazides: An Easy Access to Functionalized Azadipeptides

We report a copper-catalyzed alkynylation of azadipeptides using ethynylbenziodoxolone (EBX) reagents. Non-symmetrical ynehydrazides could be obtained in 25-97% yield using azaglycine derivatives as nucleophiles. The transfor-mation is compatible with most functional groups naturally occurring on amino acid side-chains and allows the transfer of silyl-, alkyl- and aryl-substituted alkynes. The obtained α-alkynyl azaglycine products could be further functionalized by nucleophilic attack or cycloaddition on the triple bond.