Weiss’ Reagents: A synthetically useful class of iodine(III) coordination compounds

Metathesis Reactions between Heavy d-8 Fluorides and I(III)–Pyridine Complexes

“…14,15 The solvent was removed in vacuo followed by the addition of CDCl 3 giving a deep red solid which was filtered and re-dissolved in CD 3 CN The results obtained from this reaction raise a question as to whether the observed products were being mediated by oxidation of Au(III) to a Au(V), as the chemistry of 8R with transition metals is dominated by oxidative processes. 16 A possible mechanism based on the products is oxidation to a d-6 intermediate (9Au), followed by oxidative fluorination of PhI generated in the oxidation to give the final products. 8R is known to be able to oxidize d-8 Pd(II) or Pt(II) compounds to give d-6 +4 oxidation state products or intermediates.…”

Dearomatization of Electron‐Deficient Phenols to ortho‐Quinones: Bidentate Nitrogen‐Ligated Iodine(V) Reagents

“…In recent years, our laboratory has reported on the unique reactivity and synthetic applications of (bis)cationic nitrogen‐ligated I(III) reagents, or N ‐HVIs ( 4 , Scheme B) . We, and others, have found that I(III) N ‐HVIs of the type [PhI(het) 2 ]2OTf, which possess two datively bound nitrogen ligands, have dramatically enhanced and novel reactivities over their neutral counterparts . We were therefore intrigued by a 2002 report by the group of Zhdankin disclosing the synthesis and characterization of bidentate nitrogen‐ligated I(V) species with a 2,2′‐bipyridine ligand ( 5 a ), for which no studies on its reactivity or synthetic applications have been reported .…”

“…[16] We,and others,h ave found that I(III) N-HVIs of the type [PhI-(het) 2 ]2OTf, which possess two datively bound nitrogen ligands,h ave dramatically enhanced and novel reactivities over their neutral counterparts. [17] We were therefore intrigued by a2 002 report by the group of Zhdankin disclosing the synthesis and characterization of bidentate nitrogen-ligated I(V) species with a2 ,2'-bipyridine ligand (5a), for which no studies on its reactivity or synthetic applications have been reported. [18] We hypothesized that these bidentate I(V) scaffolds,o rB i(N)-HVIs,c ould unlock novel reactivity for I(V) reagents,analogous to their I(III) N-HVI counterparts,a nd potentially enable oxidation of challenging,p reviously unreactive electron-deficient phenols to ortho-quinones.Furthermore,the presence of the bidentate nitrogen ligands could provide advantages for reagent design by 1) providing afunctional platform to allow facile tuning of the redox potentials and 2) addressing practical issues common to I(V) reagents [12] through generation of am ore monomeric reagent composition.…”

Heterocyclic Group Transfer Reactions with I(III) N-HVI Reagents: Access to N-Alkyl (Heteroaryl)onium Salts via Olefin Aminolactonization

“…Recently, our laboratory and others have been exploring the synthetic applications of (bis)cationic nitrogen-ligated hypervalent iodine (III) reagents, or N-HVIs (8, Figure 1d) 23,24 . N-HVIs possess two datively bound heterocyclic nitrogen ligands on the central iodine, resulting in altered and often novel reactivity relative to their common ArIX2 counterparts.…”

“…To date, N-HVIs have been applied to umpolung heteroatom activations 25,26 , oxidative couplings and fragmentations [27][28][29][30] , and access to high valent transition metal complexes 24,31 , however the role of the heterocyclic ligands has been limited to modulating reagent reactivity. In recognizing the growing need for improved approaches to (heteroaryl)onium salts, we wondered if N-HVIs could serve as "heterocyclic group transfer" reagents to access diverse N-alkyl (heteroaryl)onium salts through incorporation of the heterocyclic ligand into a substrate of interest.…”