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

Abstract

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
JournalScience
Volume381
Issue number6657
DOIs
StatePublished - Aug 4 2023

All Science Journal Classification (ASJC) codes

  • General

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