Electrochemically Induced Sequential Phosphorylation/Cyclization Access to Phosphorylated Pyridophenanthridines

A novel electrochemical method for synthesizing phosphorylated pyrido-4,3,2-gh-phenanthridine derivatives has been developed via a cascade phosphorylation/cyclization reaction. This approach employs a Cp2Fe-assisted electrochemical cycle to induce phosphonyl radical addition/cyanide insertion/intramolecular cyclization, achieving target products in yields of up to 91%. The reaction features mild conditions and a broad functional group tolerance. Notably, preliminary pharmacological screening indicates that some synthesized compounds show promising inhibitory effects against selected cancer cell lines in vitro.