Substituent Effects in Bioorthogonal Diels-Alder Reactions of 1,2,4,5-Tetrazines.

ABSTRACT: 1,2,4,5-Tetrazines are increasingly used as reactants in bioorthogonal chemistry due to their high reactivity in Diels-Alder reactions with various dienophiles. Substituents in the 3- and 6-positions of the tetrazine scaffold are known to have a significant impact on the rate of cycloadditions; this is commonly explained on the basis of frontier molecular orbital theory. In contrast, we show that reactivity differences between commonly used classes of tetrazines are not controlled by frontier molecular orbital interactions. In particular, we demonstrate that mono-substituted tetrazines show high reactivity due to decreased Pauli repulsion, which leads to a more asynchronous approach associated with reduced distortion energy. This follows the recent Vermeeren-Hamlin-Bickelhaupt model of rea

SUBMITTER: Houszka N 

PROVIDER: S-EPMC10946812 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature