Substituted Diaziridines via [2 + 1] Annulation of Dialkyl Azodicarboxylates with Diazo Esters and <i>In Situ</i> Pyridinium Ylides

Herein, we report the [2 + 1] annulation reactions of dialkyl azodicarboxylate with various diazoesters and <i>in situ</i> generated pyridinium ylides, resulting in the formation of substituted diaziridines in high yields. Notably, these reactions are conducted without any acids, bases, metal catalysts, or photosensitizers, demonstrating a robust strategy for synthesizing structurally diverse diaziridines. Furthermore, the diaziridines can be treated <i>in situ</i> with a variety of arenes, natural products, and pharmaceutical compounds, yielding a range of substituted hydrazine conjugates.