Photosensitized O2 enables intermolecular alkene cyclopropanation by active methylene compounds

Dhruba P. Poudel, Amrit Pokhrel, Raj Kumar Tak, Majji Shankar, Ramesh Giri

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Cyclopropanes are key features in many preclinical, clinical, and commercial drugs, as well as natural products. The most prolific technique for their synthesis is the metal-catalyzed reaction of an alkene with a diazoalkane, a highly energetic reagent requiring stringent safety precautions. Discovery of alternative innocuous reagents remains an ongoing challenge. Herein, we report a simple photoredoxcatalyzed intermolecular cyclopropanation of unactivated alkenes with active methylene compounds. The reaction proceeds in neutral solvent under air or dioxygen (O2) with a photoredox catalyst excited by blue light-emitting diode light and an iodine co-catalyst that is either added as molecular iodine or generated in situ from alkyl iodides. Mechanistic investigations indicate that photosensitized O2 plays a vital role in the generation of carbon-centered radicals for both the addition of active methylene compounds to alkenes and the ring closure.

Original languageEnglish (US)
Pages (from-to)545-553
Number of pages9
Issue number6657
StatePublished - Aug 4 2023

All Science Journal Classification (ASJC) codes

  • General

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