Visible-light mediated 3-component synthesis of sulfonylated coumarins from sulfur dioxide

A novel 3-component synthesis of sulfonylated coumarins from diaryliodonium salts, arylpropynoates and sulfur dioxide is reported. The reaction proceeds under mild conditions at room temperature in the absence of any catalysts. This transformation is solely driven by visible light and opens a new opportunity for the sustainable synthesis of sulfones via the direct incorporation of sulfur dioxide.