Photoinitiated by Red Light (λ 625 nm) Iodosulfonylation of Internal Alkynes to Synthesize β-Iodovinyl Sulfones.

A number of β-iodovinyl sulfones were synthesized by direct difunctionalization of internal alkynes with arenesulfonyl iodides under irradiation with red light (λ_max 625 nm) generated by an economical LED source. The products were obtained in high yields (68–99%) from equimolar amounts of the reactants. The reaction of sulfonyl iodides with internal alkynes follows a radical mechanism and provides a regioselective method of synthesis of β-iodovinyl sulfones. [ABSTRACT FROM AUTHOR]