NHC–Boryl Radical-Catalyzed [3 + 2] Cycloaddition for the Synthesis of Vinylcyclopentanes

Heteroatom-centered radicals have recently found important applications in catalyzing a series of radical transformations. Herein, we report a benzimidazolium-based <i>N</i>-heterocyclic carbene (NHC)-boryl radical-catalyzed [3 + 2] cycloaddition between vinylcyclopropanes and alkenes. Such a covalent radical catalysis process features radical addition, cyclopropane ring opening, intermolecular radical addition, ring cyclization, and radical elimination steps to deliver vinylcyclopentanes with good yields and substrate scope.