Synthesis of 6-(Arylthio)phenanthridines by Copper-Catalyzed Tandem Reactions of 2-Biaryl Isothiocyanates with Diaryliodonium Salts

A novel copper-catalyzed tandem C-S/C-C bond-forming reaction of 2-biaryl isothiocyanates with diaryliodonium salts was developed. This is the first general approach to synthesize phenanthridines from 2-biaryl isothiocyanates. This methodology has been successfully applied to the synthesis of trisphaeridine.