Synthesis of 1‑Thio-Substituted Isoquinoline Derivatives by Tandem Cyclization of Isothiocyanates

A copper-catalyzed tandem arylation–cyclization process to access 1-(arylthio)­isoquino­lines from isothiocyanates and diaryl­iodonium salts is described. It is the first general method to construct the potentially useful 1-(arylthio)­isoquino­line derivatives. Moreover, 1-(methyl­thio)­isoquinoline derivatives were also achieved successfully with MeOTf instead of diaryl­iodonium salts under metal-free conditions. Mechanistic studies reveal that these two processes proceed in different routes. This method has been successfully applied to the synthesis of quinazolinone alkaloid rutaecarpine