Synthesis of Thio and Selenoethers of Cyclic β‐Hydroxy Carbonyls and Amino Uracils: A Metal‐Free Regioselective I ₂ /DMSO Mediated Reaction

Abstract

Abstract A simple and practical method has been developed using I 2 /DMSO for the construction of C−S and C−Se bonds in pharmaceutically important cyclic β‐hydroxy carbonyls such as 4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one, 4‐hydroxy‐1‐methylquinolin‐2(1H)‐one, quinoline‐2,4‐diol and heterocyclic enamines such as amino uracil and amino pyrazole derivatives under mild reaction conditions. A series of thio and seleno ethers have been synthesized directly from thiols and selenols in the presence of in situ iodonium ion generated from the I 2 /DMSO combination in good to very good yields. This metal‐free dehydrogenative C−S and C−Se coupling reaction goes via C(sp 2 )‐H bond activation and works under conventional as well as microwave heating. Under microwave conditions, reactions complete within 15 minutes with very good yields.