2553-04-0Relevant articles and documents
Beta zeolite supported on silicon carbide for Friedel-Crafts fixed-bed reactions
Wine, Gauthier,Matta, Joseph,Tessonnier, Jean-Philippe,Pham-Huu, Cuong,Ledoux, Marc-Jacques
, p. 530 - 531 (2003)
Beta zeolite supported on silicon carbide, with high thermal conductivity and high mechanical strength, was successfully used as an active and stable catalyst for Friedel-Crafts reactions in a fixed bed configuration.
Synthesis of 2-(1-Alkoxyvinyl)anilines by Palladium/Norbornene-Catalyzed Amination Followed by Termination with Vinyl Ethers
Wang, Jie,Gu, Zhenhua
, p. 2990 - 2995 (2016)
A palladium/norbornene-catalyzed ortho-amination and ipso vinyl ether termination reaction of iodoarenes is reported. The benzyl vinyl ether serves as an efficient alternative carbonyl source in palladium/norbornene catalysis for the final ipso termination reaction to give [1-(benzyloxy)vinyl]arenes, which readily undergo hydrolysis to deliver methyl ketones under aqueous acidic conditions. The final Heck termination reaction with vinyl ethers has high branched/linear selectivity. This reaction tolerates a range of iodoarene and O-benzoylhydroxylamine substrates, and it provides a convenient way to prepare o-acetylanilines. The synthetic utility of [1-(benzyloxy)vinyl]arenes and the corresponding ketones is briefly investigated. (Figure presented.).
Zirconium-doped porous magadiite heterostructures upon 2D intragallery in situ hydrolysis-condensation-polymerization strategy for liquid-phase benzoylation
Ma, Yuewen,Sun, Huan,Sun, Qi,Zhang, Hui
, p. 67853 - 67865 (2015)
Novel zirconium-doped porous magadiite heterostructures (PMH-xZr, x = Zr/Si molar ratio) are fabricated by two-dimensional intragallery cosurfactant-directing in situ hydrolysis-condensation-polymerization method of TEOS and Zr-n-propoxide from synthetic Na-magadiite and characterized systematically by XRD, SEM/(HR)TEM, 29Si MAS NMR, BET, UV-vis DRS, NH3-TPD, pyridine FT-IR, and XPS techniques. The results indicate that the obtained PMH-xZr materials possess high surface area and high thermal stability upon effective assembly of interlayer Zr-doped meso-structural silica and the layers of magadiite. The PMH-xZr samples with x 0.2 show successful incorporation of Zr into the lattice of interlayer mesostructural silica framework leading to considerably generated Bronsted sites Zr-O(H)-Si and obviously increased Lewis sites Zr-O-Si along with well-kept layered supermicro-mesostructure, while PMH-0.2Zr shows delaminated layers. PMH-0.1Zr exhibits the highest liquid-phase benzoylation activity of anisole with benzoyl chloride (Conv. 99.5%) and yield for 4-methoxybenzophenone (4-MBP) (94.1%) due to the strongest synergy between the high concentration of surface Bronsted sites and supermicro-mesostructure. PMH-0.1Zr can be reused by no further chemical treatment for at least five runs with a slightly reduced 4-MBP yield. These PMH-xZr materials can serve as a promising solid acid catalyst and/or acidic support with high surface area and thermal stability in broad range of catalysis applications.
Asymmetric Transfer Hydrogenation of Diaryl Ketones with Ethanol Catalyzed by Chiral NCP Pincer Iridium Complexes
Huang, Zheng,Liu, Guixia,Qian, Lu,Tang, Xixia,Wang, Yulei
supporting information, (2022/02/23)
The use of a chiral (NCP)Ir complex as the precatalyst allowed for the discovery of asymmetric transfer hydrogenation of diaryl ketones with ethanol as the hydrogen source and solvent. This reaction was applicable to various ortho-substituted diaryl keontes, affording benzhydrols in good yields and enantioselectivities. This protocol could be carried out in a gram scale under mild reaction conditions. The utility of the catalytic system was highlighted by the synthesis of the key precursor of (S)-neobenodine.
Evaluation of Cyclic Amides as Activating Groups in N-C Bond Cross-Coupling: Discovery of N-Acyl-δ-valerolactams as Effective Twisted Amide Precursors for Cross-Coupling Reactions
Bisz, Elwira,Chen, Hao,Dziuk, B?a?ej,Ejsmont, Krzysztof,Lalancette, Roger,Pyle, Daniel J.,Rahman, Md. Mahbubur,Szostak, Michal,Szostak, Roman,Wang, Qi
, p. 10455 - 10466 (2021/07/31)
The development of efficient methods for facilitating N-C(O) bond activation in amides is an important objective in organic synthesis that permits the manipulation of the traditionally unreactive amide bonds. Herein, we report a comparative evaluation of a series of cyclic amides as activating groups in amide N-C(O) bond cross-coupling. Evaluation of N-acyl-imides, N-acyl-lactams, and N-acyl-oxazolidinones bearing five- and six-membered rings using Pd(II)-NHC and Pd-phosphine systems reveals the relative reactivity order of N-activating groups in Suzuki-Miyaura cross-coupling. The reactivity of activated phenolic esters and thioesters is evaluated for comparison in O-C(O) and S-C(O) cross-coupling under the same reaction conditions. Most notably, the study reveals N-acyl-δ-valerolactams as a highly effective class of mono-N-acyl-activated amide precursors in cross-coupling. The X-ray structure of the model N-acyl-δ-valerolactam is characterized by an additive Winkler-Dunitz distortion parameter ?(τ+χN) of 54.0°, placing this amide in a medium distortion range of twisted amides. Computational studies provide insight into the structural and energetic parameters of the amide bond, including amidic resonance, N/O-protonation aptitude, and the rotational barrier around the N-C(O) axis. This class of N-acyl-lactams will be a valuable addition to the growing portfolio of amide electrophiles for cross-coupling reactions by acyl-metal intermediates.
Acylboronates in polarity-reversed generation of acyl palladium(II) intermediates
Trofimova, Alina,Holownia, Aleksandra,Tien, Chieh-Hung,?irvinskas, Martynas J.,Yudin, Andrei K.
supporting information, p. 3294 - 3299 (2021/05/07)
We report a catalytic cross-coupling process between aryl (pseudo)halides and boron-based acyl anion equivalents. This mode of acylboronate reactivity represents polarity reversal, which is supported by the observation of tetracoordinated boronate and acyl palladium(II) species by 11B, 31P NMR, and mass spectrometry. A broad scope of aliphatic and aromatic acylboronates has been examined, as well as a variety of aryl (pseudo)halides.
