Dichloromethyl(diaryl) Sulfonium Salts as -Dichlorocyclopropanation Reagents.

-Dichlorocyclopropanes are important structural moieties in a range of industrial sectors and have been the focus of considerable interest within the synthetic community over the years. Synthetic methodologies to access -dichlorocyclopropanes, however, remain limited. To address this challenge, we report the development of new dichloromethyl(diaryl) sulfonium salts as reagents for the -dichlorocyclopropanation of electron-rich olefins via a free dichlorocarbene pathway under mild conditions in yields of up to 70%. This methodology provides access to previously unreported -dichlorocyclopropanes.