Stereospecific and highly stereoselective cyclopropanation reactions promoted by samarium

Samarium metal and samarium diiodide have become important tools as selective cyclopropanating agents in organic synthesis due to their high chemo-and stereoselectivity. Therefore, Sm and SmI2 are the ideal reagents to prepare cyclopropane derivatives. This tutorial review highlights C-C multiple bond cyclopropanation processes promoted by samarium or samarium diiodide.