Ketenimines are versatile C═C═N cumulene intermediates whose polarized π systems engage diverse nucleophiles and cycloaddition partners, providing efficient access to amidines, amides, enamides, β-lactams and nitrogen-containing heterocycles (Figure 1A) [1-5]. Their synthetic versatility, however, comes with an inherent reactivity–stability trade-off: electron-withdrawing substituents enhance ketenimine electrophilicity and reactivity toward nucleophiles but diminish their stability [6-11].
