BTTES is a tris(triazolylmethyl)amine-based ligand for accelerating the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) biocompatible click reactions without apparent toxicity.
Biocompatible Copper(I) Catalysts for in Vivo Imaging of Glycans.[1]
Reference:
[1] D.Soriano del Amo, et al, J. Am. Chem. Soc., 2010, 132(47), pp 16893-16899.