Construction of C-S and C-Se Bonds Mediated by Hypervalent Iodine Reagents Under Metal-Free Conditions

In the past few decades, the chemistry of hypervalent iodine reagents has undergone a flourishing development in synthetic organic chemistry owing to their mild oxidative, low toxicity, air and moisture stability, and environmentally benign features. A plethora of oxidative coupling reactions have been conducted using hypervalent iodine reagents as nonmetallic oxidants. In particular, the C-S and C-Se bond-forming reactions mediated by hypervalent iodine reagents have emerged as a powerful approach in the construction of Scontaining and Se-containing heterocycles or building blocks. In these reactions, hypervalent iodine reagents behave as strong oxidants or electrophiles and activate the S-containing or Secontaining species to form more electrophilic cationic or radical intermediates, which participate in subsequent coupling reactions. It is anticipated that this review summarizes all C–S and C-Se bonds forming reactions enabled by hypervalent iodine reagents under metal-free conditions.