- Radical reactions initiated by the photochemical cleavage of carbon-indium bonds of organoindium compounds
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Intra- and intermolecular reactions of carbon-centered radicals generated by photolysis of organoindium compounds were examined. The photolysis of vinylindium compounds and indium acetylides provided vinyl and alkynyl radicals, respectively, which were trapped with ethyl iodoacetate giving the corresponding β,γ-unsaturated esters. Allylic indium compounds, prepared from 8-bromo- or 8-iodooct-1,6-dienes and powdered indium metal, underwent an intramolecular radical cyclization to afford the 5-exo-trig product.
- Hirashita, Tsunehisa,Hayashi, Ayumi,Tsuji, Makoto,Tanaka, Jiro,Araki, Shuki
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- Utilization of renewable formic acid from lignocellulosic biomass for the selective hydrogenation and/or N-methylation
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Lignocellulosic biomass is one of the most abundant renewable sources in nature. Herein, we have developed the utilization of renewable formic acid from lignocellulosic biomass as a hydrogen source and a carbon source for the selective hydrogenation and further N-methylation of various quinolines and the derivatives, various indoles under mild conditions in high efficiencies. N-methylation of various anilines is also developed. Mechanistic studies indicate that the hydrogenation occurs via a transfer hydrogenation pathway.
- Zhou, Chao-Zheng,Zhao, Yu-Rou,Tan, Fang-Fang,Guo, Yan-Jun,Li, Yang
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p. 4724 - 4728
(2021/09/06)
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- Methylation synthesis method of N-heterocyclic compound
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The invention relates to a methylation synthesis method of an N-heterocyclic compound, which is characterized by comprising the following steps of a, methylation reaction: sequentially adding an N-heterocyclic compound and dimethyl carbonate into a reaction kettle, carrying out gas replacement, heating, keeping the temperature and pressure, and reacting, wherein the reaction temperature is 80-250DEG C, and the pressure is 0.3-8.0 MPa, and b, rectification: after the reaction is completed, reducing the pressure, carrying out reduced pressure rectification on the reaction mother liquor to obtain a methylation product, and recovering dimethyl carbonate and byproduct methanol. The dimethyl carbonate reagent is used for synthesizing the N-methylation product under the pressurization condition,and compared with methyl iodide and dimethyl sulfate, dimethyl carbonate is low in toxicity and more environmentally friendly; the reaction conversion rate is high, the operation is simple, and the reaction cost is low. Meanwhile, the methylation reaction selectivity is extremely good, and the method is suitable for high-selectivity synthesis of series products such as 1-methyl-1H-indole, 1, 3, 3-trimethyl-2-methylene indoline and the like.
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Paragraph 0015
(2021/02/06)
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- 1,3-disubstituted indoline derivative and preparation method thereof
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The invention relates to a 1,3-disubstituted indoline derivative and a preparation method thereof, and belongs to the field of organic compound synthesis. The preparation method comprises following steps: step one, according to a mole ratio of (1-3): (2-1
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- Synthesis of indolines via a photocatalytic intramolecular reductive cyclization reaction
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– Herein, we synthesized a series of indolines using a photocatalytic intramolecular reductive cyclization reaction. This reaction uses several N-allyl-2-iodoanilines in the presence of 10-phenylphenothiazine (Ph-PTZ) as an organic photocatalyst. Further,
- Yamaguchi, Eiji,Goto, Yumiko,Itoh, Akichika
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p. 177 - 185
(2020/02/04)
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- Selective C-H Olefination of Indolines (C5) and Tetrahydroquinolines (C6) by Pd/S,O-Ligand Catalysis
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Herein, we report a highly selective C-H olefination of directing-group-free indolines (C5) and tetrahydroquinolines (C6) by Pd/S,O-ligand catalysis. In the presence of the S,O-ligand, a wide range of challenging indolines, tetrahydroquinolines, and olefins was efficiently olefinated under mild reaction conditions. The synthetic potential of this methodology was demonstrated by the efficient olefination of several indoline-based natural products.
- Jia, Wen-Liang,Westerveld, Nick,Wong, Kit Ming,Morsch, Thomas,Hakkennes, Matthijs,Naksomboon, Kananat,Fernández-Ibá?ez, M. ángeles
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supporting information
p. 9339 - 9342
(2019/11/21)
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- A general copper-based photoredox catalyst for organic synthesis: Scope, application in natural product synthesis and mechanistic insights
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Organic transformations can broadly be classified into four categories including cationic, anionic, pericyclic and radical reactions. While the last category has been known for decades to provide remarkably efficient synthetic pathways, it has long been hampered by the need for toxic reagents, which considerably limited its impact on chemical synthesis. This situation has come to an end with the introduction of new concepts for the generation of radical species, photoredox catalysis – which simply relies on the use of a catalyst that can be activated upon visible light irradiation – certainly being the most efficient one. The state-of-the-art catalysts mostly rely on the use of ruthenium and iridium complexes and organic dyes, which still considerably limits their broad implementation in chemical processes: alternative readily available catalysts based on inexpensive, environmentally benign base metals are therefore strongly needed. Furthermore, expanding the toolbox of methods based on photoredox catalysis will facilitate the discovery of new light-mediated transformations. This article details the use of a simple copper complex which, upon activation with blue light, can initiate a broad range of radical reactions.
- Deldaele, Christopher,Michelet, Bastien,Baguia, Hajar,Kajouj, Sofia,Romero, Eugenie,Moucheron, Cecile,Evano, Gwilherm
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p. 621 - 629
(2018/10/04)
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- Asymmetric Cycloisomerization of o-Alkenyl-N-Methylanilines to Indolines by Iridium-Catalyzed C(sp3)?H Addition to Carbon–Carbon Double Bonds
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Highly enantioselective cycloisomerization of N-methylanilines, bearing o-alkenyl groups, into indolines is established. An iridium catalyst bearing a bidentate chiral diphosphine effectively promotes the intramolecular addition of the C(sp3)?H bond across a carbon–carbon double bond in a highly enantioselective fashion. The reaction gives indolines bearing a quaternary stereogenic carbon center at the 3-position. The reaction mechanism involves rate-determining oxidative addition of the N-methyl C?H bond, followed by intramolecular carboiridation and subsequent reductive elimination.
- Torigoe, Takeru,Ohmura, Toshimichi,Suginome, Michinori
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p. 14272 - 14276
(2017/10/23)
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- A General Copper Catalyst for Photoredox Transformations of Organic Halides
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A broadly applicable copper catalyst for photoredox transformations of organic halides is reported. Upon visible light irradiation in the presence of catalytic amounts of [(DPEphos)(bcp)Cu]PF6 and an amine, a range of unactivated aryl and alkyl halides were shown to be smoothly activated through a rare Cu(I)/Cu(I)?/Cu(0) catalytic cycle. This complex efficiently catalyzes a series of radical processes, including reductions, cyclizations, and direct arylation of arenes.
- Michelet, Bastien,Deldaele, Christopher,Kajouj, Sofia,Moucheron, Cécile,Evano, Gwilherm
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supporting information
p. 3576 - 3579
(2017/07/17)
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- Frustrated Lewis Pair Catalyzed Dehydrogenative Oxidation of Indolines and Other Heterocycles
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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.
- Maier, Alexander F. G.,Tussing, Sebastian,Schneider, Tobias,Fl?rke, Ulrich,Qu, Zheng -Wang,Grimme, Stefan,Paradies, Jan
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supporting information
p. 12219 - 12223
(2016/10/13)
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- Radical Hydrodeiodination of Aryl, Alkenyl, Alkynyl, and Alkyl Iodides with an Alcoholate as Organic Chain Reductant through Electron Catalysis
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A simple and efficient method for radical hydrodeiodination is reported. The novel approach uses electron catalysis. In situ generated Na-alcoholates are introduced as radical chain reducing reagents and reactions work with O2as cheap initiator. Hydrodeiodination works on aryl, alkenyl, alkynyl iodides and a tert-alkyl iodide also gets reduced applying the method. Albeit less general, the method is also applicable to the reduction of aryl bromides. The novel reagent is successfully used to conduct typical reductive radical cyclization reactions and mechanistic studies are reported.
- Dewanji, Abhishek,Mück-Lichtenfeld, Christian,Studer, Armido
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p. 6749 - 6752
(2016/06/09)
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- Catalytic methylation of C-H bonds using CO2 and H2
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Formation of C-C bonds from CO2 is a much sought after reaction in organic synthesis. To date, other than C-H carboxylations using stoichiometric amounts of metals, base, or organometallic reagents, little is known about C-C bond formation. In fact, to the best of our knowledge no catalytic methylation of C-H bonds using CO2 and H2 has been reported. Described herein is the combination of CO2 and H2 for efficient methylation of carbon nucleophiles such as indoles, pyrroles, and electron-rich arenes. Comparison experiments which employ paraformaldehyde show similar reactivity for the CO2/H2 system. Capturing: Carbon dioxide in the presence of H2 is shown to be an efficient methylating reagent for carbon nucleophiles such as 2-substituted indoles, pyrroles, and electron-rich arenes. Experimental data support the formal capture of formaldehyde. acac=acetylacetonate, triphos=1,1,1-tris(diphenylphosphinomethyl)ethane.
- Li, Yuehui,Yan, Tao,Junge, Kathrin,Beller, Matthias
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supporting information
p. 10476 - 10480
(2016/02/18)
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- Regioselective synthesis of substituted 1-indanols, 2,3-dihydrobenzofurans and 2,3-dihydroindoles by electrochemical radical cyclization using an arene mediator
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Electrochemical reduction of haloarenes carrying 2-(1-hydroxybut-3-enyl), 2-allyloxy or N-allyl-N-methylamino group in the presence of phenanthrene as a mediator generated the corresponding aryl radicals and gave the corresponding 5-exo cyclization produc
- Kurono, Nobuhito,Honda, Eiichi,Komatsu, Fumikazu,Orito, Kazuhiko,Tokuda, Masao
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p. 1791 - 1801
(2007/10/03)
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- Cobalt-mediated Radical Reactions in Organic Synthesis. Oxidative Cyclisations of Aryl and Alkyl Halides leading to Functionalised Reduced Heterocycles and Butyrolactones
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Reactions between the CoI species derived from cobalt(III) salen (11) or cobalt(II) salophen (12) and (O-allyl) or (O-but-3-enyl) iodophenols lead to isolatable cobalt complexes, viz. (16) and (27), which can be converted into substituted benzofurans, i.e. (17) and (23), and benzopyrans, i.e. (28) and (34); similarly, interaction between compound (36) and Co1 salen led in one step to 1,3-dimethylindole (37).Radical cyclisation of the acetal (38a) in the presence of Co1 cobaloxime leads to the cis-ring-fused alkyl cobalt complex (42), which can be converted in a preparative manner into lactone (44) following 1,2-elimination and hydrolysis/oxidation, and into lactone (53) following insertion of molecular oxygen , reduction and hydrolysis/oxidation.
- Bhandal, Harcharan,Patel, Vinod F.,Pattenden, Gerald,Russell, Jamie J.
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p. 2691 - 2701
(2007/10/02)
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