- Enhanced aqueous Suzuki-Miyaura coupling allows site-specific polypeptide 18F-labeling
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The excesses of reagents used in protein chemistry are often incompatible with the reduced or even inverse stoichiometries used for efficient radiolabeling. Analysis and screening of aqueous Pd(0) ligand systems has revealed the importance of a guanidine core and the discovery of 1,1-dimethylguanidine as an enhanced ligand for aqueous Suzuki-Miyaura cross-coupling. This novel Pd catalyst system has now allowed the labeling of small molecules, peptides, and proteins with the fluorine-18 prosthetic [ 18F]4-fluorophenylboronic acid. These findings now enable site-specific protein 18F-labeling under biologically compatible conditions using a metal-triggered reaction.
- Gao, Zhanghua,Gouverneur, Veronique,Davis, Benjamin G.
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Read Online
- Scalable electrochemical synthesis of diaryliodonium salts
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Cyclic and acyclic diaryliodonium are synthesised by anodic oxidation of iodobiaryls and iodoarene/arene mixtures, respectively, in a simple undivided electrolysis cell in MeCN-HFIP-TfOH without any added electrolyte salts. This atom efficient process does not require chemical oxidants and generates no chemical waste. More than 30 cyclic and acyclic diaryliodonium salts with different substitution patterns were prepared in very good to excellent yields. The reaction was scaled-up to 10 mmol scale giving more than four grams of dibenzo[b,d]iodol-5-ium trifluoromethanesulfonate (>95%) in less than three hours. The solvent mixture of the large-scale experiment was recovered (>97%) and recycled several times without significant reduction in yield.
- Elsherbini, Mohamed,Moran, Wesley J.
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supporting information
p. 4706 - 4711
(2021/06/11)
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- Reactions of PhIX2I(iii) oxidants with heavy triphenyl pnictines
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The reactions of [PhI(pyridine)2]2+, PhI(OAc)2and PhI(OTf)(OAc) with Ph3As, Ph3Sb and Ph3Bi are described. The reactions of [PhI(pyridine)2]2+with Ph3Sb and Ph3Bi afford dicationic Pn(v) complexes ligated by pyridine in one step. These were previously reported by Burford in multi-step syntheses. Reactions with PhI(OAc)2, which were already known for Sb and Bi giving Pn(v) diacetates, were confirmed to give the same type of compound for As. Reactions with PhI(OAc)(OTf) were less selective, resulting in the isolation of iodonium cations [Ph-I-Ph]+for As and Bi, while Ph3Sb gave an oxobridged di-antimony species characteristic of the decomposition of a high valent triflate bound species.
- Aprile, Antonino,Dutton, Jason L.,Egalahewa, Sathsara
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p. 7507 - 7513
(2020/06/21)
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- Flow Synthesis of Diaryliodonium Triflates
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A safe and scalable synthesis of diaryliodonium triflates was achieved using a practical continuous-flow design. A wide array of electron-rich to electron-deficient arenes could readily be transformed to their respective diaryliodonium salts on a gram scale, with residence times varying from 2 to 60 s (44 examples).
- Laudadio, Gabriele,Gemoets, Hannes P. L.,Hessel, Volker,No?l, Timothy
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p. 11735 - 11741
(2017/11/24)
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- Transition-Metal-Free N-Arylation of Pyrazoles with Diaryliodonium Salts
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A new synthetic method was developed for the N-arylation of pyrazoles using diaryliodonium salts. The transformation does not require any transition-metal catalyst and provides the desired N-arylpyrazoles rapidly under mild reaction condition in the presence of aqueous ammonia solution as a mild base without the use of inert atmosphere. The chemoselectivity of unsymmetric diaryliodonium salts was also explored with large number of examples.
- Gonda, Zsombor,Novák, Zoltán
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supporting information
p. 16801 - 16806
(2015/11/16)
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- Diverse reactions of PhI(OTf)2 with common 2-electron ligands: Complex formation, oxidation, and oxidative coupling
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The crystal structures of bis-pyridine stabilized iodine dications [PhI(pyr)2]2+ are reported as triflate salts, representing the first ligand supported iodine dications to be structurally characterized. The pyridine complexes are susceptible to ligand exchange in reaction with stronger N-based donors such as 4-dimethylaminopyridine. Attempts to extend this reactivity to N-heterocyclic carbene and phosphine ligands, as has been accomplished in the earlier p-block groups, resulted in redox chemistry, with oxidation of the ligands rather than coordination.
- Pell, Thomas P.,Couchman, Shannon A.,Ibrahim, Sara,Wilson, David J. D.,Smith, Brian J.,Barnard, Peter J.,Dutton, Jason L.
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p. 13034 - 13040
(2013/02/22)
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- Synthesis of diaryliodonium triflates using environmentally benign oxidizing agents
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A range of symmetric and unsymmetric diaryliodonium triflates have been prepared employing urea-hydrogen peroxide as the oxidizing agent. The use of aqueous hydrogen peroxide and catalytic systems with methylrhenium trioxide in the oxidation of iodoarenes
- Merritt, Eleanor A.,Malmgren, Joel,Klinke, Felix J.,Olofsson, Berit
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experimental part
p. 2277 - 2280
(2009/12/08)
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- High-yielding one-pot synthesis of diaryliodonium triflates from arenes and iodine or aryl iodides
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Unsymmetric and symmetric diaryliodonium triflates are synthesized from both electron-deficient and electron-rich substrates in a fast, high yielding, and operationally simple protocol employing arenes and aryl iodides or iodine. The Royal Society of Chem
- Bielawski, Marcin,Olofsson, Berit
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p. 2521 - 2523
(2008/02/11)
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- Efficient and general one-pot synthesis of diaryliodonium triflates: Optimization, scope and limitations
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Symmetrical and unsymmetrical diaryliodonium triflates have been synthesized from both electron-deficient and electron-rich arenes and aryl iodides with mCPBA and triflic acid. A thorough investigation of the optimization, scope and limitations has resulted in an improved one-pot protocol that is fast, high-yielding, and operationally simple. The reaction has been extended to the direct synthesis of symmetrical iodonium salts from iodine and arenes, conveniently circumventing the need for aryl iodides.
- Bielawski, Marcin,Zhu, Mingzhao,Olofsson, Berit
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p. 2610 - 2618
(2008/09/19)
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- Reaction of iodoarenes with potassium peroxodisulfate/trifluoroacetic acid in the presence of aromatics. Direct preparation of diaryliodonium triflates from iodoarenes
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Diaryliodonium triflates have been directly prepared by reaction of some iodoarenes with aromatic substrates in good yields by using K2S2O8/CF3COOH/CH2Cl2. Treatment of a variety of iodoare
- Hossain, Md. Delwar,Kitamura, Tsugio
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p. 6955 - 6960
(2007/10/03)
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- Xenon difluoride-trimethylsilyl isocyanate-triflic acid as a new system for the amination of aromatic compounds
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In the title system, OCNXeOSO2CF3 is formed, which readily oxidises iodobenzene to [PhI+-NCO -OTf]. The direct amination of aromatic substrates is possible with the use of XeF2-Me3SiNCO-CF3SO3H.
- Pirkuliev,Brel,Akhmedov,Zefirov,Stang
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p. 172 - 173
(2007/10/03)
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- An efficient ligand exchange reaction of (e)-[β- (trifluoromethanesulfonyloxy)ethenyl](phenyl)iodonium triflates with aryl- and alkynyllithium reagents leading to diaryl- and alkynyliodonium triflates
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Reaction of (E)-[β-(trifluoromethanesulfonyloxy)- ethenyl](phenyl)iodonium triflates with aryl- and alkynyllithium reagents gave aryl(phenyl)- and alkynyl(phenyl)iodonium triflates in high yields and selectively. These reactions indicate that ligand exchange takes place efficiently at the hypervalent iodine atom and provides another approach to diaryl- and alkynyliodonium salts.
- Pirguliyev, Namig Sh,Brel, Valery K.,Akhmedov, Navruz G.,Zefirov, Nikolai S.
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- Aromatic C-H insertion of β-phenoxyalkylidenecarbenes generated by reaction of alkynyl(p-phenylene)bisiodonium ditrifluoro-methanesulfonates (ditriflates) with phenoxide anions
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Reaction of alkynyl(p-phenylene)bisiodonium ditriflates with sodium phenoxide in methanol provides 2-substituted benzofurans in 49-62% yields. This result indicates that β-phenoxyalkylidenecarbenes are generated by the reaction with phenoxide anion and undergo novel intramolecular aromatic C-H insertion to afford benzofurans. 2-Phenoxy-2-phenylethenylidene generated analogously in situ underwent competing processes of aromatic C-H insertion and 1,2-phenyl migration. The corresponding reactions with 4-substituted phenoxide ions also afforded 5-substituted benzofurans and, as the minor products, 2-aryloxy-1-iodoalk-1-enes which were probably derived from the intermediate vinyliodonium salts. Reactions of alkynyl(p-phenylene)bisiodonium ditriflates with sodium [2H5]phenoxide (98% 2H) in methanol gave deuterated 2-alkylbenzofurans in 35-40% yields and the hydrogen at the 3-position of the benzofurans was deuterated completely. This result strongly supports selective aromatic C-H insertion of the in situ generated β-phenoxyalkylidenecarbenes.
- Kitamura, Tsugio,Zheng, Lei,Fukuoka, Takahiro,Fujiwara, Yuzo,Taniguchi, Hiroshi,Sakurai, Makoto,Tanaka, Ryuichi
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p. 1511 - 1515
(2007/10/03)
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- Improved preparation of diaryliodonium triflates
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A reagent prepared from a 1:2 molar ratio of (diacetoxy)iodobenzene [PhI(OAc)2] and trifluoromethanesulfonic acid (TfOH) reacts with aromatic compounds to give diaryliodonium triflates in fairly good yields. The high reactivity and high para se
- Kitamura,Matsuyuki,Taniguchi
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p. 147 - 148
(2007/10/02)
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