Diaryliodonium Salts: Aryl Transfer Reagents for Alkyne Difunctionalization

Abstract

In recent years, hypervalent iodine reagents have emerged as powerful tools in synthesis. This highlight paper describes recent developments in the application of diaryliodonium salts for a variety of transformations. It is shown how the extremely electrophilic nature of these reagents can be exploited to difunctionalize alkynes in cascade reactions to access complex scaffolds.

Diaryliodoniums Salts as Coupling Partners for Transition-Metal Catalyzed C- and N-Arylation of Heteroarenes

“…During the last decade, noteworthy improvement in the synthesis and use of diaryliodonium salts has been reported [9][10][11][12][13][14][15][16][17][18][19][20][21]. Owing to their electron-deficient nature at the iodine center and to the excellent leaving-group ability of the iodoarene, diaryliodonium salts are frequently employed as aromatic electrophiles in aryl transfer processes [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. Seminal contributions from the Pike, Olofsson, Kita and Stuart groups highlighted the efficiency and the selectivity of this aforementioned reaction.…”

Hypervalent iodine compounds: reagents of the future

“…[37][38][39][40] Numerous recent reviews have been dedicated to synthetic applications of several specific classes of hypervalent iodine compounds. Aryliodonium salts have attracted significant interest as electrophilic arylating reagents [41][42][43][44][45][46][47] and precursors for Positron Emission Tomography (PET). 48,49 Iodonium ylides have also been recently utilized as PET precursors for nucleophilic radiofluorination.…”

I2O5-Mediated Iodocyclization Cascade of N-(1-Arylallyl)pyridine-2-amines with Concomitant C═C Bond Cleavage: A Synthesis of 3-Iodoimidazo[1,2-a]pyridines

“…Alkenes and alkynes are ubiquitous structural units in organic molecules, and they serve as useful building blocks for the construction of molecule diversities due to their easy availability and high reactivity. , In this regard, recently, the 1,2-difunctionalizations of CC and CC bonds have received special attention because such reactions usually allow for the synthesis of complex molecules in simple operation and step-economy manner (Scheme a). , As compared to the extensive studies on the 1,2-difunctionalizations of CC and CC bonds, the 1,1 (or 2,2)-difunctionalizations of CC and CC moieties involving C–C bond cleavage (C sp 2 –C sp 3 , C sp 2 –C sp 2 , C sp –C sp 3 , CC, or CC bond, Scheme b), however, have been relatively underexplored − because the cleavage of C–C bond remains a great challenge owing to the extraordinarily large bond association energy of C–C bonds . Yet, this type of strategy would provide an alternative way to make full use of alkenes and alkynes as synthetic platforms in organic synthesis (Scheme b). − Regarding difunctionalization with concomitant CC bond cleavage, for example, we and Zhao’s group independently realized a splitting of CC bonds in chalcones with concomitant 2,2-oxygenation/arylation of the cleaved sp 2 -carbon resulting in the formation of 9,10-phenanthraquinones and α-ketoamides (esters), respectively; Meldal and co-workers reported a cleavage of CC bonds in solid-supported peptide olefins followed by 2,2-amination/arylation of the scissored sp 2 -carbon to afford pyrroloisoquinolines; very recently, Wu and Liu reported a palladium-catalyzed oxidative cleavage of CC bonds with a concomitant double amination of the resulting sp 2 -carbon fragments to yield quinazolinones; Xu and Liu , described a transition-metal-free cleavage of CC or CC bonds followed by reassembling the cleaved fragments with S 8 and amides to access aryl thioamides.…”