Can Biomimetic Zinc Compounds Assist a (3 + 2) Cycloaddition Reaction? A Theoretical Perspective

Compounds bearing tetrazole rings are valuable facets in numerous branches of chemistry including metabolic imaging and the production of drugs and high-energy materials. Synthesis of tetrazoles with the help of organocatalysts has intensively been explored, while enzyme-directed click chemistry has attracted less attention and was only used in inhibitor design so far. Herein, we have investigated the possibility of a biomimetic catalyst based on a Lewis acid approach by exploring the anionic cycloaddition of azide and acetonitrile catalyzed by ZnBr2 in comparison with different biomimetic Zn(II) models. Density functional based calculations in the gas phase and with implicit solvation indicate that a variety of bioinspired zinc complexes should be able to catalyze tetrazole formation with catalytic enhancements comparable to zinc bromide salts. Such bioinspired routes could provide new possibilities for the stereo- and regioselectively controlled synthesis of tetrazoles.