1,3-Hydro-di/monofluoromethylation of N, N'-Cyclic Azomethine Imines with HCF2SO2Na/H2CFSO2Na via Photocatalytic Radical Addition

J Org Chem. 2024 Aug 16;89(16):11747-11752. doi: 10.1021/acs.joc.4c00679. Epub 2024 Jul 31.

Abstract

The radical 1,3-hydro-di/monofluoromethylation of N,N'-cyclic azomethine imines with HCF2SO2Na/H2CFSO2Na via photoredox catalysis is described. This reaction exhibits broad functional group compatibility, providing the desired products in good yields. However, CF3SO2Na failed to produce the trifluoromethyl product. DFT calculations revealed that the transition state activation energy for radical trifluoromethylation was significantly higher and the isotropic charge repulsion makes it difficult for the CF3 radical to transfer electrons.