Aryl Transfer Selectivity in Metal-Free Reactions of Unsymmetrical Diaryliodonium Salts

Aromatic rings are found in a wide variety of products, including pharmaceuticals, agrochemicals, and functional materials. Diaryliodonium salts are new reagents used to transfer aryl groups under both metal-free and metal-catalyzed reactions and thereby synthesize arene-containing compounds. This minireview focuses on recent studies in selective aryl transfer reactions from unsymmetrical diaryliodonium salts under metal-free conditions. Reactions reported from 2007 to 2017, which represents a period of significant growth in diaryliodonium salt chemistry, are presented and organized by the type of reactive intermediate formed in the reaction. Specifically, reactions involving lambda(3)-iodane, lambda(3)-iodane radical anions, aryl radicals, and arynes are discussed. Chemoselectivity trends in aryl transfer are compared and contrasted across reaction intermediates and translation to potential auxiliaries are posited.