2106-66-3Relevant academic research and scientific papers
Direct Arylation of Simple Arenes with Aryl Bromides by Synergistic Silver and Palladium Catalysis
Tlahuext-Aca, Adrian,Lee, Sarah Yunmi,Sakamoto, Shu,Hartwig, John F.
, p. 1430 - 1434 (2021)
The direct, catalytic arylation of simple arenes in small excess with aryl bromides is disclosed. The developed method does not require the assistance of directing groups and relies on a synergistic catalytic cycle in which phosphine-ligated silver complexes cleave the aryl C-H bond, while palladium catalysts enable the formation of the biaryl products. Mechanistic experiments, including kinetic isotope effects, competition experiments, and hydrogen-deuterium exchange, support a catalytic cycle in which cleavage of the C-H bond by silver is the rate-determining step.
Deuterium Exchange between Arenes and Deuterated Solvents in the Absence of a Transition Metal: Synthesis of D-Labeled Fluoroarenes
Salamanca, Vanesa,Albéniz, Ana C.
supporting information, p. 3206 - 3212 (2020/04/15)
Fluoroarenes can be selectively deuterated by H/D exchange with common deuterated solvents in the presence of a catalytic amount of an alkali metal carbonate or, for the less acidic arenes, stoichiometric quantities of potassium phosphate. This is a susta
Sodium Diisopropylamide in Tetrahydrofuran: Selectivities, Rates, and Mechanisms of Arene Metalations
Algera, Russell F.,Ma, Yun,Collum, David B.
, p. 15197 - 15204 (2017/10/31)
Sodium diisopropylamide (NaDA)-mediated metalations of arenes in tetrahydrofuran (THF)/hexane or THF/Me2NEt solutions are described. A survey of >40 benzenoid- and pyridine-based arenes with a range of substituents demonstrates the efficacy and regioselectivity of metalation. Metalations of activated disubstituted arenes and selected monosubstituted arenes are rapid at -78 °C. Rate studies of 1,3-dimethoxybenzene and related methoxylated arenes show exclusively monomer-based orthometalations with two or three coordinated THF ligands. Rate studies of the isotopic exchange of benzene and monosubstituted arenes with weakly activating groups reveal analogous di- and trisolvated monomer-based metalations. Cooperative inductive, mesomeric, steric, and chelate effects are discussed.
Base-Catalyzed Aryl-B(OH)2 Protodeboronation Revisited: From Concerted Proton Transfer to Liberation of a Transient Aryl Anion
Cox, Paul A.,Reid, Marc,Leach, Andrew G.,Campbell, Andrew D.,King, Edward J.,Lloyd-Jones, Guy C.
supporting information, p. 13156 - 13165 (2017/09/26)
Pioneering studies by Kuivila, published more than 50 years ago, suggested ipso protonation of the boronate as the mechanism for base-catalyzed protodeboronation of arylboronic acids. However, the study was limited to UV spectrophotometric analysis under acidic conditions, and the aqueous association constants (Ka) were estimated. By means of NMR, stopped-flow IR, and quenched-flow techniques, the kinetics of base-catalyzed protodeboronation of 30 different arylboronic acids has now been determined at pH > 13 in aqueous dioxane at 70 °C. Included in the study are all 20 isomers of C6HnF(5-n)B(OH)2 with half-lives spanning 9 orders of magnitude: a and Sδ values, kinetic isotope effects (2H, 10B, 13C), linear free-energy relationships, and density functional theory calculations, we have identified a mechanistic regime involving unimolecular heterolysis of the boronate competing with concerted ipso protonation/C-B cleavage. The relative Lewis acidities of arylboronic acids do not correlate with their protodeboronation rates, especially when ortho substituents are present. Notably, 3,5-dinitrophenylboronic acid is orders of magnitude more stable than tetra-and pentafluorophenylboronic acids but has a similar pKa.
Rapid and safe ASAP acquisition with EXACT NMR
Ndukwe,Shchukina,Kazimierczuk,Butts
supporting information, p. 12769 - 12772 (2016/11/02)
The dangerously high power levels required for fast ASAP-HSQC and ASAP-HMQC experiments are mitigated by employing EXACT NMR. The utility of this technique is demonstrated by application of the EXACT ASAP-HSQC to chemical reaction monitoring, accelerating
Selective deuteration of (hetero)aromatic compounds via deutero-decarboxylation of carboxylic acids
Grainger, Rachel,Nikmal, Arif,Cornella, Josep,Larrosa, Igor
supporting information; experimental part, p. 3172 - 3174 (2012/06/04)
A practical, mild and highly selective protocol for the monodeuteration of a variety of arenes and heteroarenes is presented. Catalytic amounts of Ag(i) salts in DMSO/D2O are shown to facilitate the deutero-decarboxylation of ortho-substituted
Polyfluoroorganoboron-oxygen compounds. 2 [1]: Base-catalysed hydrodeboration of polyfluorophenyl(dihydroxy)boranes
Frohn,Adonin,Bardin,Starichenko
, p. 2834 - 2838 (2008/10/08)
Polyfluorinated phenyl(dihydroxy)boranes C6H5-nFnB(OH)2 (n = 3 - 5) underwent hydrodeboration (formal replacement of the (dihydroxy)boryl group by hydrogen) in the presence of bases (MeOH, 33% H2O-MeO
