Metal-free iodine-catalyzed direct cross-dehydrogenative coupling (CDC) between pyrazoles and thiols

A green and efficient iodine-catalyzed cross-dehydrogenative C-S coupling method for the synthesis of C-4 sulfenylated pyrazoles has been initially developed under metal-free conditions. This new method is highly efficient and practical, and the starting materials are readily available. The present method should provide a useful strategy for the construction of different thiol-substituted pyrazole motifs.