Radical-mediated 1,2-nitrogen migration from silicon to carbon through iron LMCT photochemistry

Radical-mediated migration provides an unconventional approach to reorganizing C–N connectivity, yet known transformations have largely relied on nitrogen migration from carbon-, nitrogen- or oxygen-linked precursors. Here we report the discovery of a visible-light-driven, FeCl₃-catalysed reaction that reveals silicon as a distinct origin for nitrogen translocation. Mechanistic experiments and computational studies support a pathway in which an Si–N intermediate is generated in situ and undergoes 1,2-nitrogen migration from silicon to carbon, ultimately forming an imine intermediate. This intermediate serves as a versatile branching point for subsequent bond formation, enabling modular incorporation of N-, O-, S- and Se-based nucleophiles, as well as intramolecular cyclization and cascade annulation. Variation of the nitrogen-containing component, hydrosilane and trapping partner provides access to a broad range of difunctionalized products and heterocyclic frameworks. Experimental mechanistic studies and DFT calculations collectively support a direct intramolecular Si-to-C nitrogen migration through a three-membered Si–C–N transition state. These findings expand the bonding environments from which radical nitrogen migration can originate and establish Si–N bonds as a potential entry point for nitrogen translocation and complexity-generating synthesis.