624-38-4Relevant articles and documents
Transition-Metal-Free Coupling of Polyfluorinated Arenes and Functionalized, Masked Aryl Nucleophiles
Finck, Lucie,Oestreich, Martin
, p. 11061 - 11064 (2021/06/12)
A chemoselective C(sp2)?C(sp2) coupling of sufficiently electron-deficient fluorinated arenes and functionalized N-aryl-N’-silyldiazenes as masked aryl nucleophiles is reported. The fluoride-promoted transformation involves the in situ generation of the aryl nucleophile decorated with various sensitive functional groups followed by a stepwise nucleophilic aromatic substitution (SNAr). These reactions typically proceed at room temperature within minutes. This catalytic process allows for the functionalization of both coupling partners, furnishing highly fluorinated biaryls in good yields.
Orthogonal Stability and Reactivity of Aryl Germanes Enables Rapid and Selective (Multi)Halogenations
Deckers, Kristina,Fricke, Christoph,Schoenebeck, Franziska
supporting information, p. 18717 - 18722 (2020/08/25)
While halogenation is of key importance in synthesis and radioimaging, the currently available repertoire is largely designed to introduce a single halogen per molecule. This report makes the selective introduction of several different halogens accessible. Showcased here is the privileged stability of nontoxic aryl germanes under harsh fluorination conditions (that allow selective fluorination in their presence), while displaying superior reactivity and functional-group tolerance in electrophilic iodinations and brominations, outcompeting silanes or boronic esters under rapid and additive-free conditions. Mechanistic experiments and computational studies suggest a concerted electrophilic aromatic substitution as the underlying mechanism.
Boosting Low-Valent Aluminum(I) Reactivity with a Potassium Reagent
Eyselein, Jonathan,F?rber, Christian,Grams, Samuel,Harder, Sjoerd,Langer, Jens
supporting information, p. 15982 - 15986 (2020/07/04)
The reagent RK [R=CH(SiMe3)2 or N(SiMe3)2] was expected to react with the low-valent (DIPPBDI)Al (DIPPBDI=HC[C(Me)N(DIPP)]2, DIPP=2,6-iPr-phenyl) to give [(DIPPBDI)AlR]?K+. However, deprotonation of the Me group in the ligand backbone was observed and [H2C=C(N-DIPP)?C(H)=C(Me)?N?DIPP]Al?K+ (1) crystallized as a bright-yellow product (73 %). Like most anionic AlI complexes, 1 forms a dimer in which formally negatively charged Al centers are bridged by K+ ions, showing strong K+???DIPP interactions. The rather short Al–K bonds [3.499(1)–3.588(1) ?] indicate tight bonding of the dimer. According to DOSY NMR analysis, 1 is dimeric in C6H6 and monomeric in THF, but slowly reacts with both solvents. In reaction with C6H6, two C?H bond activations are observed and a product with a para-phenylene moiety was exclusively isolated. DFT calculations confirm that the Al center in 1 is more reactive than that in (DIPPBDI)Al. Calculations show that both AlI and K+ work in concert and determines the reactivity of 1.
Synthesis, structure, and synthetic potential of arenediazonium trifluoromethanesulfonates as stable and safe diazonium salts
Filimonov, Victor D.,Krasnokutskaya, Elena A.,Kassanova, Assia Zh.,Fedorova, Valentina A.,Stankevich, Ksenia S.,Naumov, Nikolay G.,Bondarev, Alexander A.,Kataeva, Veronika A.
, p. 665 - 674 (2018/09/14)
Aromatic diazonium salts are valuable building blocks for organic synthesis; however, in most cases, they are unstable, unsafe, poorly soluble, and/or expensive. In this paper, we have shown that a variety of stable and safe arenediazonium triflates ArN2+ TfO– can be obtained easily and in high yields by diazotization of anilines with tert-butyl nitrite in the presence of trifluoromethanesulfonic acid. Arenediazonium triflates are relatively shelf-stable in the dry state. They dissolve well in water, as well as polar and even nonpolar organic solvents. Less than 800 J/g of energy is released during the thermal decomposition of these salts, which indicates their explosion safety. Arenediazonium triflates have a high reactivity in the known reactions of diazonium chemistry, and undergo an unusual metal-free chlorodediazonization reaction with chloroform and CCl4.
Metathesis-active ligands enable a catalytic functional group metathesis between aroyl chlorides and aryl iodides
Lee, Yong Ho,Morandi, Bill
, p. 1016 - 1022 (2018/09/06)
Current methods for functional group interconversion have, for the most part, relied on relatively strong driving forces which often require highly reactive reagents to generate irreversibly a desired product in high yield and selectivity. These approaches generally prevent the use of the same catalytic strategy to perform the reverse reaction. Here we describe a catalytic functional group metathesis approach to interconvert, under CO-free conditions, two synthetically important classes of electrophiles that are often employed in the preparation of pharmaceuticals and agrochemicals—aroyl chlorides (ArCOCl) and aryl iodides (ArI). Our reaction design relies on the implementation of a key reversible ligand C–P bond cleavage event, which enables a non-innocent, metathesis-active phosphine ligand to mediate a rapid aryl group transfer between the two different electrophiles. Beyond enabling a practical and safer approach to the interconversion of ArCOCl and ArI, this type of ligand non-innocence provides a blueprint for the development of a broad range of functional group metathesis reactions employing synthetically relevant aryl electrophiles.
Functional Group Transposition: A Palladium-Catalyzed Metathesis of Ar-X σ-Bonds and Acid Chloride Synthesis
De La Higuera Macias, Maximiliano,Arndtsen, Bruce A.
supporting information, p. 10140 - 10144 (2018/08/23)
We describe the development of a new method to use palladium catalysis to form functionalized aromatics: via the metathesis of covalent σ-bonds between Ar-X fragments. This transformation demonstrates the dynamic nature of palladium-based oxidative addition/reductive elimination and offers a straightforward approach to incorporate reactive functional groups into aryl halides through exchange reactions. The reaction has been exploited to assemble acid chlorides without the use of high energy halogenating or toxic reagents and, instead, via the metathesis of aryl iodides with other acid chlorides.
Visible-Light-Induced Decarboxylative Iodination of Aromatic Carboxylic Acids
Jiang, Min,Yang, Haijun,Jin, Yunhe,Ou, Lunyu,Fu, Hua
supporting information, p. 1572 - 1577 (2018/06/26)
A convenient, efficient and practical visible-light-induced decarboxylative iodination of aromatic carboxylic acids has been developed, and the corresponding aryl iodides were obtained in good yields. The method shows some advantages including the use of readily available aromatic carboxylic acids as the starting materials, simple and mild conditions, high efficiency, wide substrate scope and tolerance of various functional groups.
An efficient gram scale synthesis of aryl iodides from aryl diazofluoroborates in water under mild conditions
Gholap, Somnath S.
, p. 594 - 599 (2018/06/26)
Transition metal-free synthesis of synthetically valuable aryl iodides from aryl diazofluroborates in water under mild conditions has been described. Majority of synthesized aryl iodides are obtained in quantitative yields (>99%) under present reaction conditions. The structural effects due to the substituents present on aryl diazofluoroborates did not show any satisfactory effect on the yields of the aryl iodides. Hence, the methodology presented here was found to be adventitious for the quantitative production of synthetically valuable aryl iodides.
A general electrochemical strategy for the Sandmeyer reaction
Liu, Qianyi,Sun, Beiqi,Liu, Zheng,Kao, Yi,Dong, Bo-Wei,Jiang, Shang-Da,Li, Feng,Liu, Guoquan,Yang, Yang,Mo, Fanyang
, p. 8731 - 8737 (2018/12/10)
Herein we report a general electrochemical strategy for the Sandmeyer reaction. Using electricity as the driving force, this protocol employs a simple and inexpensive halogen source, such as NBS, CBrCl3, CH2I2, CCl4, LiCl and NaBr for the halogenation of aryl diazonium salts. In addition, we found that these electrochemical reactions could be performed using anilines as the starting material in a one-pot fashion. Furthermore, the practicality of this process was demonstrated in the multigram scale synthesis of aryl halides using highly inexpensive graphite as the electrode. A series of detailed mechanism studies have been performed, including radical clock and radical scavenger study, cyclic voltammetry analysis and in situ electron paramagnetic resonance (EPR) analysis.
Copper-catalysed aromatic-Finkelstein reactions with amine-based ligand systems
Jin, Xiaodong,Davies, Robert P.
, p. 2110 - 2117 (2017/07/22)
A new efficient and low-cost ligand, diethylenetriamine, has been utilised to promote the iodination of 16 different bromo-substrates via the copper catalysed Finkelstein halogen exchange reaction under mild conditions. In contrast to earlier methods, the use of inert atmosphere conditions was not required to obtain high yields and purity. Studies on the speciation of the catalyst in solution indicate rapid disproportionation of copper(i) in the presence of diethylenetriamine to give copper(0) and a bis-ligated copper(ii) complex which is characterised by X-ray diffraction. This copper(ii) complex was also shown to be catalytically active in the halogen exchange reaction. In contrast, no significant disproportionation was observed using dimethylethylenediamine as the ligand, and the solid-state structures of a copper(i) dimeric complex and a 2D polymeric network of copper(i) iodide tetramers are reported. The catalytic activity of diethylenetriamine and dimethylethylenediamine with both copper(i) and copper(ii) salts are compared, and possible mechanistic implications discussed.
