Utility of Dysprosium Diiodide and Metallic Dysprosium as Reductants in Cyclopropanation Reactions of Alkenes with Dichloromethane

We have found that the combination of dysprosium diiodide and dichloromethane can serve as an effective methylene transfer reagent for cyclopropanation of unfunctionalized alkenes. Furthermore, a Dy/I 2 system has also proved to be effective in the cyclopropanation of alkenes and CH 2 Cl 2 .