Ru-Catalyzed Benzannulation of Vinyl Sulfoxonium Ylide with Electron-Deficient Alkynes and Alkenes.

Herein, we report carbene-mediated benzannulation of vinyl sulfoxonium ylides with electron-deficient alkynes and alkenes to synthesize oxygenated arenes. This protocol features excellent regioselectivity, a broad substrate scope, and mild reaction conditions. Mechanistic studies revealed that the reaction proceeds through furan generation, cycloaddition, ring cleavage, and aromatization cascades. The synthesized arenes have been utilized in diverse product transformations and arene ring homologation.