Aziridination of a Single Carbon Atom in Alkenes via Energy Transfer Catalysis.

Traditional alkene aziridination relies on the alkene's reaction with a (formal) nitrene species, whereby the alkene provides both carbon atoms for the formed heterocycle. In contrast to this paradigm, we herein report a divergent manifold consisting of intermolecular aziridination at a single alkene site with concomitant functionalization of the second alkene site. This process unlocks alternative chemical space from alkenes through energy transfer-catalyzed difunctionalization of alkenyl boronates and silanes toward spring-loaded imine intermediates and their subsequent facile conversion to an aziridine involving a 1,2-aza-(bora-)Brook rearrangement. The use of visible light and the absence of metals, additional bases, and external heating allow for mild reaction conditions that furnish unprotected and highly substituted aziridines.