Proposal for the Metallacycle Pathway during the Cyclopropanation Catalyzed by Cobalt−Schiff Base Complexes

The density functional study of the cobalt(II) complex-catalyzed cyclopropanation revealed that the cobalt(II)−Schiff base complex without an ethylene bridge would be flexible enough to transform into the cis-β conformer while approaching the olefin; consequently, the metallacycle pathway would be preferred, while the ethylene bridge would stabilize the planar conformer to allow reaction via the concerted mechanism.