Stable α ‐Nitroaziridines Enable Ketenimine Chemistry

ABSTRACT Highly reactive electron‐deficient ketenimines are versatile yet short‐lived intermediates whose synthetic use is constrained by the coupled conditions required for their generation and capture. Here, we introduce bottleable α ‐nitroaziridines that store ketenimine reactivity in stable, isolable precursors. Accessible through modular gram‐scale synthesis, these precursors tolerate chromatographic purification and long‐term storage and remain dormant when premixed with water and nucleophiles. Mild activation triggers ring opening and nitrite extrusion, releasing ketenimines on demand for diverse N ‐, O ‐, and C ‐trapping reactions, cyclizations, cycloadditions, and late‐stage conjugations, with selected transformations proceeding under water‐containing conditions. Isotope labeling, nitrite‐release quantification, in situ infrared (IR) spectroscopy, convergence with an independent ketenimine‐generation pathway, and density functional theory (DFT) calculations support the release mechanism. By temporally decoupling reaction‐environment preassembly from transient‐intermediate generation, α ‐nitroaziridines establish a compatibility‐before‐activation strategy for ketenimine chemistry.