1,3-Hydro-di/monofluoromethylation of N , N '-Cyclic Azomethine Imines with HCF 2 SO 2 Na/H 2 CFSO 2 Na via Photocatalytic Radical Addition.

The radical 1,3-hydro-di/monofluoromethylation of N,N' -cyclic azomethine imines with HCF 2 SO 2 Na/H 2 CFSO 2 Na via photoredox catalysis is described. This reaction exhibits broad functional group compatibility, providing the desired products in good yields. However, CF 3 SO 2 Na 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 CF 3 radical to transfer electrons.