Methylcyclopropene-containing monosaccharides can be used to attach methylcyclopropene groups to glycoconjugates via metabolic labeling [1-3] followed by subsequent labeling with Tetrazine-containing detection reagents via Cu(I)-free Tetrazine-Cyclopropene Ligation.
A number of CLICKable monosaccharides are available for metabolic glycan labeling.
 Spaete et al. (2014) Expanding the scope of cyclopropene reporters for the detection of metabolically engineered glycoproteins by Diels–Alder reactions. Beilstein J. Org. Chem. 10:2235.
 Spaete et al. (2014) Rapid labeling of metabolically engineered cell-surface glycoconjugates with a carbamate-linked cyclopropene reporter. Bioconj. Chem. 25:147.
 Patterson et al. (2014) Improved cyclopropene reporters for probing protein glycosylation. Mol. BioSyst. 10:1693.
 Patterson et al. (2012) Functionalized cyclopropenes as bioorthogonal chemical reporters. J. Am. Chem. Soc. 134:18643.