Description Building block for the introduction by Fmoc SPPS of an amino acid bearing an alkyne side chain. Such derivatives are useful tools for the synthesis of cyclic peptides by an alkyne-alkyne Glaser coupling, involving Cu(OAc)2/pyridine and heating to 60 °C using microwaves.. Any other use of the reagent may be covered by third party patents and it is the customers′ obligation to check this if they have the intention to use them for other purposes beside the recommended use.