Photoinduced Methylthio Radical Generation from Methylthiophosphonium Salt

The production of methylthio radical typically relies on gaseous methanethiol or dimethyl disulfide. Herein, we present a new and straightforward method for the photogeneration of methylthio radical from methylthiophosphonium salt, enabling the synthesis of methylthiophenanthridines via charge transfer complex strategy. In this approach, the methylthiophosphonium salt acts as the electron acceptor, while 2‐isocyanobiaryls serve as the electron donors. This strategy is distinguished by its simplicity in both conditions and operation, and can be extended for the generation of various alkyl(aryl)thio radicals.