Iron-mediated ligand-to-metal charge transfer enables 1,2-diazidation of alkenes

Given the widespread significance of vicinal diamine units in organic synthesis, pharmaceuticals and functional materials, as well as in privileged molecular catalysts, an efficient and practical strategy that avoids the use of stoichiometric strong oxidants is highly desirable. We herein report the application of ligand-to-metal charge transfer (LMCT) excitation to 1,2-diazidation reactions from alkenes and TMSN3 via a coordination-LMCT-homolysis process with more abundant and greener iron salt as the catalyst. Such a LMCT-homolysis mode allows the generation of electrophilic azidyl radical intermediate from Fe–N3 complexes poised for subsequent radical addition into carbon–carbon double bond. The generated carbon radical intermediate is further captured by iron-mediated azidyl radical transfer, enabling dual carbon–nitrogen bond formation. This protocol provides a versatile platform to access structurally diverse diazides with high functional group compatibility from readily available alkenes without the need of chemical oxidants.