Cu-Mediated Thianthrenation and Phenoxathiination of Arylborons

Great success in synthetic chemistry is motivated by the development of novel and reactive linchpins for carbon-carbon and carbon-heteroatom bond formation reactions, that has dramatically altered chemists’ approach to building molecules. Herein, we report the readily synthesis of aryl sulfonium salts, a novel versatile electrophilic linchpin, via an unprecedented Cu-mediated thianthrenation and phenoxathiination of commercially available arylborons with thianthrene and phenoxathiine, providing a series of aryl sulfonium salts in high efficiency. More importantly, by leveraging the sequential Ir-catalyzed C–H borylation and Cu-mediated thianthrenation of arylborons, the formal thianthrenation of arenes are also achieved. As the Ir-catalyzed C–H borylation with undirected arenes normally occurred at the less steric hindrance position, thus providing a complementary method for thianthrenation of arenes in comparison with the electrophilic thianthrenation. This process is capable of late-stage functionalization of a series of pharmaceuticals, which might find wide synthetic applications in both industry and academic sectors.