Cyclopropane rings are pivotal structural motifs in medicinal chemistry, yet their synthesis remains constrained by the reliance on unstable carbene precursors with limited structural diversity. Herein, we report a photocatalytic metalloradical strategy for cyclopropanation of aryl alkenes using bench-stable gem-dichloroalkanes as practical carbene equivalents, facilitated by earth-abundant zirconium catalysis. This method accommodates a broad range of vinylarenes with notable functional group tolerance under mild visible-light-driven conditions. Mechanistic investigations reveal that an open-shell Zr(III) metalloradical intermediate plays a crucial role in activating inert C(sp3)–Cl bonds, offering insights into zirconium-mediated radical processes. The utility of this method is exemplified in the streamlined preparation of medicinal scaffolds, with carbonyls serving as practical substitutes for nonstabilized carbenes.
Liao et al. (Fri,) studied this question.