TCO reagents

TCO (trans-cycloctene) reagents are commonly used in catalyst-free protein-protein bioconjugation, labelling live cells and polymer coupling (such as tetrazine hydrogels). The inverse-electron demand Diels-Alder cycloaddition reaction (IEDDA) between TCO compounds and tetrazines produces a conjugate at extremely high rates and selectivity. The water-tolerant IEDDA reaction is then followed by a retro-DA reaction to eliminate Nitrogen gas.