A visible light mediated alkyl sulfonylative cascade using Hantzsch esters via SO 2 insertion.

We hereby report a visible light mediated alkyl sulfonylative cascade cyclization of alkynyl and dialkynyl cyclohexadienones via SO 2 insertion. The protocol utilizes alkyl Hantzsch esters as the alkyl source and DABSO as the SO 2 source with 4-CzIPN as the organophotocatalyst. A variety of dihydrochromenone derivatives were obtained in good yields under mild energy efficient conditions. Additionally, fluorescence quenching and control studies were carried out to probe the mechanism.