Cycloaddition Reactions of Alkene Radical Cations using Iron(III)‐Phenanthroline Complex

Single electron oxidation of electron‐rich alkenes using the iron(III)‐phenanthroline complex produced electrophilic alkene radical cations, which promoted efficient radical cation [2+1] cycloaddition reactions with diazo compounds. Subsequent chain propagation afforded tri‐ and tetra‐substituted cyclopropanes. This methodology was also expanded to [3+2] cycloaddition reactions with vinyl diazoesters, validating this sustainable, first‐row transition metal iron system for the single electron redox reactions.