Diastereoselective Transfer of Tri(di)fluoroacetylsilanes‐Derived Carbenes to Alkenes.

Stereoselective cyclopropanation reaction of alkenes is usually achieved by metal complexes via singlet‐metal‐carbene intermediates. However, previous transition‐metal‐catalyzed cyclopropanation of alkenes with acylsilanes afforded low diastereoselectivity. Herein, we report the first visible‐light‐induced transition‐metal‐free cyclopropanation reaction of terminal alkenes with trifluoroacetylsilanes and difluoroacetylsilanes. Both aromatic and aliphatic alkenes as well as electron‐deficient alkenes are suitable substrates for the highly cis‐selective [2+1] cyclization reaction. A combination of experimental and computational studies identified triplet carbenes as being key intermediates in this transformation. The gram scale reaction and late‐stage functionalization demonstrated the synthetic potential of this strategy. [ABSTRACT FROM AUTHOR]