New perspectives for iodine (III) reagents in (hetero)biaryl coupling reactions

The biomimetic phenolic and non-phenolic oxidative coupling approach to the construction of biaryl connections represents an alternative to other known methodologies, such as Ullmann or Stille reactions, with the advantage that no functionalization at the coupling positions is required. However, most of the reagents commonly used for oxidative bond formation are highly toxic and environmentally harmful. This review focuses on the use of easily handle and less toxic hypervalent iodine reagents phenyliodine(III)bis(trifluoroacetate) or PIFA and phenyliodine(III)diacetate or PIDA, to perform such a key transformation as the formation of the biaryl linkage is in Synthetic Organic Chemistry. This methodology has been used in the synthesis of symmetric and unsymmetric biaryl compounds in both inter- and intramolecular fashion with high yields and complete regioselectivity. Moreover, chiral biaryl derivatives have been successfully synthesized employing these reagents. On the other hand, recent results have demonstrated that a combination of the advantages shown by this type of reagents, with those derived from solid phase organic synthesis can be successfully applied to improve the construction of derivatives incorporating the biaryl framework. Finally, this methodology had not been applied to perform the synthesis of aryl-heteroaryl bonds so far. This review also summarizes our recent advances toward this end.