Photoredox phosphonomethylation/cyclization of alkenes enabled by an EDA complex

Abstract

The phosphonomethyl unit is an important functional group in medicinal chemistry. ICH₂PO(R¹R²) is a commercially available phosphonomethylation reagent. However, the synthesis of phosphonomethyl-substituted cyclic molecules by using ICH₂PO(R¹R²) mainly relies on noble metal-catalyzed methods. Herein, the photoredox phosphonomethylation/cyclization of alkenes has been developed. Mechanistically, the electron donor–acceptor (EDA) complex formed in situ between ICH₂PO(R¹R²) and 1,4-diazabicyclo[2.2.2]octane (DABCO) is key to this reaction. This method does not require photocatalysts, oxidants, or reducing agents and operates under mild conditions, making it suitable for the late-stage modification of drug molecules.