Visible-light-induced photoredox aerobic coupling of sulfonium ylides and amines leading to the E-selective formation of 2-amino-2-butene-1,4-diones†

A novel visible-light-induced photoredox three-component aerobic coupling reaction of sulfoxonium ylides and amines is reported. This protocol provides a general strategy for the construction of structurally valuable highly functionalized 2-amino-2-butene-1,4-dione scaffolds in a chemo- and regioselective manner. This methodology stands out for its mild conditions, no requirement of organic oxidants or other additives, and good E-selectivity. Mechanistic studies suggested that dioxygen serves as a dual functional reagent not only in the photoredox cycle (light reaction) but also in the aerobic oxidative coupling (dark reaction).