Description
Tetrazines demonstrate exceptionally fast cycloaddition kinetics (up to 30 000 M-1 s-1) with trans-cyclooctenes (TCO) as the dienophile, the fastest kinetics ever reported for any bioorthogonal reaction. In addition, inverse-Electron-Demand Diels-Alder reaction of tetrazines trans-cyclooctenea forms a stable covalent bond and does not require Cu-catalyst or elevated temperatures. In applications such as in vivo cancer imaging or pre‐targeted cell labeling studies where rapid reaction kinetics is a must, a faster hydrogen substituted Cy®5 Tetrazine probe would be a probe of choice.