The copper(I)-catalyzed reaction of alkenyldiazoacetates and iminoiodinanes affords functionalized azetine derivatives. This process is consistent with the formation of an aziridinyldiazoacetate intermediate, which gives rise to the four-membered heterocycles by metal-catalyzed ring expansion. The resulting azetine structure is a direct precursor of azeditine-2-carboxylic acid derivatives (EWG=electron-withdrawing group).
![Copper(I)-catalyzed [3+1] cycloaddition of alkenyldiazoacetates and iminoiodinanes: Easy access to substituted 2-azetines](https://www.iciq.org/wp-content/uploads/2014/03/CopperI-catalyzed-31_9221.gif)