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

We report a copper-catalyzed alkynylation of azadipeptides using ethynylbenziodoxolone (EBX) reagents. Nonsymmetrical ynehydrazides could be obtained in 25-97% yield using azaglycine derivatives as nucleophiles. The transformation 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 alpha-alkynyl azaglycine products could be further functionalized by nucleophilic attack or cycloaddition on the triple bond.

Automated summary

In this study, a copper-catalyzed alkynylation of azadipeptides using ethynylbenziodoxolone (EBX) reagents was reported. Nonsymmetrical ynehydrazides could be obtained in high yields using azaglycine derivatives as nucleophiles. The reaction is compatible with various functional groups naturally occurring on amino acid side chains and allows the transfer of different substituents. The obtained products can be further functionalized.