Stable α-Nitroaziridines Enable Ketenimine Chemistry

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.