Investigation of Iodonium Trifluoroborate Zwitterions as Bifunctional Arene Reagents

Abstract

The synthesis of a new family of iodonium zwitterions, in which the formal anion is a trifluoroborate moiety, is reported. These reagents present very good stability and have high resistance toward benzyne formation. Their structures were confirmed by X-ray crystallographic analysis and were further investigated using DFT calculations. QTAIM analysis supports an ionic, noncovalent, I···BF interaction, in accordance with a true zwitterionic nature. Preliminary results of synthetic applications, the arylation of phenolates and trifluoroborate group functionalization, are reported.

Deacetylative Aryl Migration of Diaryliodonium Salts with C(sp2)–N Bond Formation toward ortho-Iodo N-Aryl Sulfonamides

“…Besides, ortho -functionalized diaryliodonium salts such as phenyl­[2-(trimethylsilyl)­phenyl]­iodonium triflate (Kitamura’s reagent, Scheme a, C ) and pseudocyclic arylbenz­iodoxaborole triflates (Scheme a, D ) by Yoshimura and Zhdankin can readily generate benzyne species for the reactions . Notably, Legault reported the new zwitterions of aryliodine­(III) bearing a 2-trifluoroborate moiety in the arylation of phenolates (Scheme a, E ) . Wencel-Delord and Colobert developed ortho -sulfoxide diaryliodonium salts, which enabled C–N coupling reactions with indolines in excellent atropselectivity (Scheme a, F ) .…”

Intramolecular Aryl Migration of Diaryliodonium Salts: Access to ortho‐Iodo Diaryl Ethers

“…Notably, the structures of B and C in Scheme b, including a trimethylsilyl and boronic acid group, respectively, were used as efficient benzyne precursors . Recently, the group of Legault reported new trifluoroborate zwitterions, bearing a neighboring trifluoroborate moiety, in the arylation of phenolates ( D , Scheme b) . Given our interest in exploring the activation of vicinal C−H bonds of diaryliodonium salts for efficient synthesis of aromatic compounds (Scheme c), we hypothesized that iodonium salts that incorporate a heteroatom in the ortho position might have a neighboring effect, thereby leading to unprecedented reactivity.…”

Hypervalent Iodonium Zwitterions and Nucleophilic Aromatic Substitution: A Multiple-Step Experiment in Organic Chemistry

“…The general term iodonium zwitterion is used for different types of HIC in which the iodine atom is connected to two ligands and carries a positive formal charge compensated by a negative charge in the same molecule . The Legault group recently reported the synthesis of a family of novel iodonium trifluoroborate zwitterions and confirmed their structure by X-ray diffraction . In addition, it could be demonstarted that these zwitterions can act as bifunctional reagents in the arylation of phenolate derivatives.…”