Accessing Azetidines through Magnesium‐Mediated Nitrogen Group Transfer from Iminoiodinane to Donor‐Acceptor Cyclopropanes

Herein, we report a Lewis acid‐mediated ring expansion of donor‐acceptor cyclopropanes (DACs) to substituted azetidines via nucleophilic nitrogen group transfer from readily accessible iminoiodinane. This protocol operates under mild, transition‐metal‐free conditions, and showcases excellent chemoselectivity, along with broad functional group tolerance. We report for the first time that challenging alkyl donor‐acceptor cyclopropanes can undergo ring expansion leading to aliphatic azetidines without relying on external oxidants or precious transition‐metal catalysts. Mechanistically, the coordination of a magnesium (Mg)‐Lewis acid to the DAC promotes nucleophilic ring opening with a putative Mg‐amide species generated from the iminoiodinane under the reaction conditions to furnish the azetidine products.