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Updated: Mar 13, 2026
Harnessing the Bioorthogonal Inverse Electron Demand Diels-Alder Cycloaddition for Pretargeted PET Imaging
Published on: February 3, 2015
Optimized Tetrazine Derivatives for Rapid Bioorthogonal Decaging in Living Cells
Xinyuan Fan1,2, Yun Ge1, Feng Lin1
1Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
Abstract:
The inverse-electron-demand Diels-Alder (iDA) reaction has recently been repurposed as a bioorthogonal decaging reaction by accelerating the elimination process after an initial cycloaddition between trans-cyclooctene (TCO) and tetrazine (TZ). Herein, we systematically surveyed 3,6-substituted TZ derivatives by using a fluorogenic TCO-coumarin reporter followed by LC-MS analysis, which revealed that the initial iDA cycloaddition step was greatly accelerated by electron-withdrawing groups (EWGs) while the subsequent elimination step was strongly suppressed by EWGs. In addition, smaller substituents facilitated the decaging process. These findings promoted us to design and test unsymmetric TZs bearing an EWG group and a small non-EWG group at the 3- and 6-position, respectively. These TZs showed remarkably enhanced decaging rates, enabling rapid iDA-mediated protein activation in living cells.
