5905-11-3Relevant academic research and scientific papers
In Situ Preparation of Palladium Nanoparticles for C-2 Selective Arylation of Indoles in Agro-Waste Extract Based Mixed Solvents
Jin, Weiwei,Liu, Chenjiang,Liu, Tianxiang,Sun, Yajun,Wang, Bin,Wang, Rui,Xia, Yu,Zhang, Yonghong
supporting information, p. 2470 - 2473 (2021/06/25)
An efficient and practical method for the in situ generation of palladium nanoparticles was successfully established in a water extract of pomelo peel ash. The produced palladium nanoparticles were characterized by energy-dispersive X-ray spectroscopy elemental mapping, field emission scanning electron microscopy, high-resolution transmission electron microscope, X-ray powder diffraction, and showed high catalytic activity for selective C-2 arylation of indoles. A series of 2-arylindoles were smoothly installed in moderate to good yields through the direct palladium-catalyzed cross-coupling reactions of indoles and iodoarenes without external ligand, base, oxidant, and preinstallation directing group.
C2–H Arylation of Indoles Catalyzed by Palladium-Containing Metal-Organic-Framework in γ-Valerolactone
Anastasiou, Ioannis,Van Velthoven, Niels,Tomarelli, Elena,Lombi, Aurora,Lanari, Daniela,Liu, Pei,Bals, Sara,De Vos, Dirk E.,Vaccaro, Luigi
, p. 2786 - 2791 (2020/03/24)
An efficient and selective procedure was developed for the direct C2–H arylation of indoles using a Pd-loaded metal–organic framework (MOF) as a heterogeneous catalyst and the nontoxic biomass-derived solvent γ-valerolactone (GVL) as a reaction medium. The developed method allows for excellent yields and C-2 selectivity to be achieved and tolerates various substituents on the indole scaffold. The established conditions ensure the stability of the catalyst as well as recoverability, reusability, and low metal leaching into the solution.
Room-Temperature Palladium(II)-Catalyzed Direct 2-Arylation of Indoles with Tetraarylstannanes
Liu, Yuxia,Wang, Chao,Huang, Linjuan,Xue, Dong
supporting information, p. 1613 - 1618 (2020/09/15)
A palladium(II)-catalyzed direct 2-arylation of indoles by tetraarylstannanes with oxygen (balloon) as the oxidant at room temperature has been developed. Various tetraarylstannanes can be employed as aryl sources for 2-arylation of indoles in up to 89% yield, providing a practical and efficient catalytic protocol for accessing 2-arylindoles.
Transition-Metal-Free Synthesis of Heterobiaryls through 1,2-Migration of Boronate Complex
Paul, Swagata,Das, Kanak Kanti,Manna, Samir,Panda, Santanu
supporting information, p. 1922 - 1927 (2020/02/04)
The synthesis of a diverse range of heterobiaryls has been achieved by a transition-metal-free sp2–sp2 cross-coupling strategy using lithiated heterocycle, aryl or heteroaryl boronic ester and an electrophilic halogen source. The construction of heterobiaryls was carried out through electrophilic activation of the aryl–heteroaryl boronate complex, which triggered 1,2-migration from boron to the carbon atom. Subsequent oxidation of the intermediate boronic ester afforded heterobiaryls in good yield. A comprehensive 11B NMR study has been conducted to support the mechanism. The cross coupling between two nucleophilic cross coupling partners without transition metals reveals a reliable manifold to procure heterobiaryls in good yields. Various heterocycles like furan, thiophene, benzofuran, benzothiophene, and indole are well tolerated. Finally, we have successfully demonstrated the gram scale synthesis of the intermediates for an anticancer drug and OLED material using our methodology.
Direct C-H bond activation: Palladium-on-carbon as a reusable heterogeneous catalyst for C-2 arylation of indoles with arylboronic acids
Bhattacharjee, Prantika,Bora, Utpal,Boruah, Purna K.,Das, Manash R.
, p. 7675 - 7682 (2020/06/09)
Direct C(sp2)-H bond functionalization of indoles with arylboronic acids is achieved using palladium supported on carbon as a reusable heterogeneous catalyst in the presence of an oxidant under mild conditions. The current protocol formed exclusive C-2 selective products without the aid of any ligand or directing group. The catalyst is reusable for up to four catalytic cycles with the retention of catalytic efficiency.
NaNO2/K2S2O8-mediated Selective Radical Nitration/Nitrosation of Indoles: Efficient Approach to 3-Nitro- and 3-Nitrosoindoles
Shoberu, Adedamola,Li, Cheng-Kun,Tao, Ze-Kun,Zhang, Guo-Yu,Zou, Jian-Ping
, p. 2255 - 2261 (2019/04/13)
JPZ acknowledges financial support from the National Natural Science Foundation of China (No. 21172163, 21472133), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and Key Laboratory of Organic Synthesis of Jiangsu Province (KJS1749). (Figure presented.).
Preparation method for indole compound
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Paragraph 0067-0068, (2019/12/25)
The invention provides a preparation method for an indole compound, and belongs to the technical field of preparation of heterocyclic compounds. The preparation method comprises the following steps: with 1,2-dichloromethane as a solvent, silver oxide as a catalyst and 2-ethynylaniline and derivatives thereof as raw materials, subjecting the raw materials to a complete reaction at 10 to 60 DEG C inthe presence of p-toluenesulfonic acid monohydrate, carrying out spin-drying so as to obtain a crude product, and carrying out column chromatographic separation so as to obtain a fine product namelythe indole compound. The preparation method provided by the invention has the advantages of short preparation steps, mild reaction conditions, high product yield and low cost, and provides a universalnovel method for preparation of the indole compound.
A Three-Component Strategy for Benzoselenophene Synthesis under Metal-Free Conditions Using Selenium Powder
Ni, Penghui,Tan, Jing,Zhao, Wenqi,Huang, Huawen,Xiao, Fuhong,Deng, Guo-Jun
, p. 3518 - 3522 (2019/05/24)
An efficient three-component benzoselenophenes formation has been developed from substituted indoles, acetophenones, and selenium powder under metal-free conditions. 2-Aryl indoles played an important role to promote benzoselenophene formation from acetophenone derivatives and selenium powder. One C-C and two C-Se bonds were selectively formed to provide 40 new benzoselenophenes in good yields.
Catalytic Access to Indole-Fused Benzosiloles by 2-Fold Electrophilic C-H Silylation with Dihydrosilanes
Omann, Lukas,Oestreich, Martin
supporting information, p. 767 - 776 (2017/04/21)
A protocol for the catalytic synthesis of indole-fused benzosiloles starting from 2-aryl-substituted indoles and dihydrosilanes is reported. Compared to known procedures, this method does not require prefunctionalized starting materials and, hence, allows for a rapid access to those siloles. The net reaction is a 2-fold electrophilic C-H silylation catalyzed by cationic Ru-S complexes. Both reaction steps were separately investigated, and these results eventually led to the development of a two-step procedure. By preparing new Ru-S complexes with different weakly coordinating anions (WCAs), it is also shown that the latter can have a dramatic influence on the outcome of these reactions. Furthermore, the substrate scope of the new method is discussed.
Frustrated Lewis Pair Catalyzed Dehydrogenative Oxidation of Indolines and Other Heterocycles
Maier, Alexander F. G.,Tussing, Sebastian,Schneider, Tobias,Fl?rke, Ulrich,Qu, Zheng -Wang,Grimme, Stefan,Paradies, Jan
supporting information, p. 12219 - 12223 (2016/10/13)
An acceptorless dehydrogenation of heterocycles catalyzed by frustrated Lewis pairs (FLPs) was developed. Oxidation with concomitant liberation of molecular hydrogen proceeded in high to excellent yields for N-protected indolines as well as four other substrate classes. The mechanism of this unprecedented FLP-catalyzed reaction was investigated by mechanistic studies, characterization of reaction intermediates by NMR spectroscopy and X-ray crystal analysis, and by quantum-mechanical calculations. Hydrogen liberation from the ammonium hydridoborate intermediate is the rate-determining step of the oxidation. The addition of a weaker Lewis acid as a hydride shuttle increased the reaction rate by a factor of 2.28 through a second catalytic cycle.
