Here we demonstrate a fundamentally new reactivity of the silyl enol ether functionality utilizing an in situ-generated “io-donitrene”-like species. The present transformation inserts a single nitrogen atom between the silyl enol ether olefinic carbons with concomitant cleavage of the C=C bond without fragmentation. Overall, this facile transformation converts a C-nucleophilic silyl enol ether to the corresponding C-electrophilic N-acyl-N,O-acetal. This unprecedented access to alpha-amidoalkylating agents enables facile and modular derivatization, allowing deep exploration of unchartered chemical space. Applications presented herein include late-stage nitrogen insertion into carbon skeletons of complex natural products with previously unattainable regioselectivity, as well as modified conditions for 15N labeling of amides and lactams.