Radical Promoted C(sp2)-S Formation and C(sp3)-S Bond Cleavage: Access to 2-Substituted Thiochromones.

A radical-promoted cyclization of methylthiolated alkynones with diverse radical precursors has been developed. This strategy occurred via a C(sp2)-S bond formation and C(sp3)-S cleavage sequence and allows an efficient synthesis of a variety of phosphoryl-, sulfenyl-, CF2COOEt-, and acyl-containing thiochromone derivatives in moderate to good yields under mild conditions.