Radical Cascade\nCyclization of <i>N</i>‑(<i>o</i>‑Cyanobiaryl)acrylamides\nwith Sulfonium Salts via\nSynergetic Photoredox and Copper Catalysis

As the magic methyl effect is well acknowledged in pharmaceutical\nmolecules, the development of simple and efficient methods for the\ninstallment of methyl groups on complex molecules is highly coveted.\nHence, we provide a general strategy for radical cascade cyclization\nof <i>N</i>-(<i>o</i>-cyanobiaryl)acrylamides\nby utilizing sulfonium salts as the sources of methyl radical and\nmerging photoredox and copper catalysis. This novel protocol can access\na wide variety of methylation or remote thioether-substituted benzo-fused <i>N</i>-heterocycle derivatives, which can be easily transformed\ninto diverse highly valuable sulfone and sulfoximine compounds via\nlate-stage diversification. Moreover, to further demonstrate the synthetic\nutility of this conversion, the methyl(phenyl)sulfide, which serves\nas both raw material and byproduct, can be recovered and reused in\nthis transformation. The scale-up experiment for the one-pot two-step\nprocess directly offers the target product in good yield under the\nstandard conditions.