Having established the compatibility of the reaction with different amino acids, we next explored the variety of alkynes that could be transferred with azapeptide 2b as partner. A variety of EBXs could be easily prepared by using established procedures or the most recent protocol developed by our group (1 h reaction time, no additives, no purification). High yields of alkynylated azapeptides could be maintained when replacing the TIPS group by a simple phenyl (3b) or mesityl (3c) substituent. The structure of 5b was determined by X-ray diffraction and displayed a trans-amide geometry in the solid state. Electron-withdrawing substituent on the aryl ring such as fluoride or bromide were well tolerated affording 5c and 5d with only a slight decrease in yield. Alkyl substituted alkynes could also be transferred. Alkynylated azapeptide 5e bearing a methyl group was obtained in 40% yield, and higher yield could be obtained with a cyclopropyl group (5f). Having a chloride on the alkyl chain was tolerated and 5g could be obtained in 53% yield. Scheme 3. Scope of EBX reagents.