Hypervalent iodine reagents as a new entrance to organocatalysts

The catalytic utilization of hypervalent iodine reagents, largely in consideration of economical and environmental viewpoints, is a most attractive strategy due to their unique features as extremely useful oxidants, with mild, safe, and environmentally friendly characteristics. In addition to a system based on electrochemical reoxidation conditions, new reliable catalytic methods have emerged in recent years that can broaden the scope of the catalytic concept. For these contributions, a catalytic strategy is now available for performing many representative types of oxidative bond-forming reactions and alcohol oxidations mediated by hypervalent iodines, some of which even include key transformations for natural product synthesis. A suitable choice of terminal oxidants, e.g., m-chloroperbenzoic acid (mCPBA) or Oxone, for generation of active hypervalent iodine(iii) or (v) species from iodoarenes in situ, has led to recent rapid expansion in this field. This feature article highlights the historical background and the efforts made to realize the catalytic utilization of these reagents, especially with focus on iodine(iii).