Base-Promoted Annulation of <i>o</i>-(Cyanomethyl)aryl Thioester with Thiophenols to Access 3-Thiolated Isoquinolones

An efficient annulation approach to forming 3-thiolated isoquinolones from readily accessible <i>o</i>-(cyanomethyl)aryl thioesters and thiophenols has been established. This metal-free annulation is achieved by taking advantage of solvent-free reactions with no precaution to exclude water or air, enabling broad substrate scope and good functionality tolerance. Furthermore, the protocol is scalable and offers facile access to valuable isoquinolones without chromatography.