Metal-catalyzed σ-bond rearrangement

The metal ion-catalyzed σ-bond rearrangement is a collection of chemical reactions that occur with highly strained organic compounds are treated with metal ions like Ag+, Rh(I), or Pd(II) based reagents. [2+2] ring openings are sometimes observed:
 * [[Image:Metal-ion-catalyzed-sigma-bond-rearrangement.png|500px|Scheme 1. Metal-ion-catalyzed σ-bond rearrangement]]

These rearrangements proceed via oxidative addition of strained rings. Such processes are related to the activation of cyclopropanes by transition metals.