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

A number of beta-iodovinyl sulfones were synthesized by direct difunctionalization of internal alkynes with arenesulfonyl iodides under irradiation with red light (lambda(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 beta-iodovinyl sulfones.