Iodine-mediated photoinduced tuneable disulfonylation and sulfinylsulfonylation of alkynes with sodium arylsulfinates

An efficient transition-metal free iodine-mediated tuneable disulfonylation and sulfinylsulfonylation of alkynes with sodium arylsulfinates under visible light irradiation has been developed. This photochemical protocol offers broad substrate scope of 1,2-bissulfonylethenes with high functional group tolerance and good yields under mild reaction conditions. In addition, it was found that β-sulfinyl alkenylsulfones can be obtained in the absence of base. It is proposed that the reactions proceed via sulfonyl and sulfinyl radicals. The iodine-mediated reaction of alkynes with sodium arylsulfinates under blue light irradiation gives either disulfonylation or sulfinylsulfonation depending on reaction conditions.