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.