Iodine-Mediated Photocatalytic Disulfonylation of Allenes with Sodium Sulfinates

The disulfonylation of allenes is an actively researched area in synthetic chemistry yet faces challenges, including regioselectivity, competing monosulfonylation pathways, instability of reactive intermediates, and the lack of suitable sulfonylation reagents. Herein, we report a iodine-mediated photocatalytic disulfonylation of allenes for synthesizing 2,3-disulfonylpropene derivatives, employing readily available and cost-effective sodium sulfinate as a sulfonylation reagent without pre-synthetic preparation. Notably, the cooperative interaction between the iodine-mediated equilibrium and photoinduced electron transfer circumvents harsh reaction conditions traditionally required for disulfonylation, initiates reactions efficiently, stabilizing sulfonylated allylic radical intermediates, and directs the reaction pathway to prevent byproducts. Mechanistic studies, including radical trapping/clock experiments, intermediate capture experiments, cyclic voltammogram tests, Stern-Volmer experiments, ultraviolet-visible absorption spectra, and light on/off experiments, confirm the photocatalytic iodine-mediated pathway.