azabicyclic cyclopropanes (with Co catalyst). The rhodium-catalyzed 2H-pyrrole formation involving hydrogen shift is supported by deuterium-labeling experiments. The control experiments in the cobalt-catalyzed reaction indicate that the bicyclic aziridines as the primary product undergo a skeletalrearrangement assisted by metal iodide salts.
A phosphine‐free iridium‐catalyzed reaction of isoxazol‐5(4H)‐ones (isoxazolones) has been developed, and affords 2H‐azirines through decarboxylation and ring contraction. This method provides an efficient and environmentally benign protocol which could replace the conventional approaches used to synthesize 2H‐azirines.