- Coal. Kinetics of O-Alkylation
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The kinetic reactivities of the acidic hydroxyl groups in coal were measured.The chemical action of quaternary ammonium hydroxyde bases in the presence of alkylating agents was used as the probe.Both Illinois No. 6 bituminous and Rawhide subbituminous coals contain aromatic and aliphatic hydroxyls as well as lesser amounts of carboxylic acids.Illinois coal was found to O-alkylate at a faster rate than Rawhide coal.The reactivities of the acidic functional groups in the coals were correlated to the reactivity of acidic groups in model compounds.This was accomplished by both relative and absolute kinetic rate measurements on each coal and a series of model systems.It was discovered that the activation energy associated with the nucleophilic displacement determined the rate of O-alkylation of the coal.Therefore, the rate of the reaction is not limited by mass transport of the chemical reagents into the coal structure.In this sense, O-alkylation of coal is a most unique reaction.
- Liotta, Ronald,Brons, Glen
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Read Online
- C-H Triflation of BINOL Derivatives Using DIH and TfOH
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C-H trifluoromethanesulfonyloxylation (triflation) of 1,1′-bi-2-naphthol (BINOL) derivatives has been established under mild conditions using 1,3-diiodo-5,5-dimethylhydantoin (DIH) and trifluoromethanesulfonic acid (TfOH). Up to eight TfO groups can be introduced in a single operation. The resulting highly oxidized BINOL derivatives can be successfully converted to 8,8′-dihydroxy BINOL and bisnaphthoquinone compounds. Mechanistic studies suggested that C-H triflation occurs in the form of an aromatic substitution reaction via the in situ formation of a radical cation.
- Nakazawa, Hironobu,Sako, Makoto,Masui, Yu,Kurosaki, Ryo,Yamamoto, Shunya,Kamei, Toshiyuki,Shimada, Toyoshi
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Read Online
- 2-Methoxynaphthalene at 173 K
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2-Methoxynaphthalene, C11H10O, crystallizes as a nearly planar molecule, with the methoxy group adopting a synperiplanar conformation with respect to the Cα atom. A search of the Cambridge Structural Database [Allen & Kennard (1993). Chem. Des. Autom. News, 8, 31-37] reveals that this conformation is characteristic of the α-methoxynaphthalene moiety, because, for each of the four exceptions found, a valid explanation can be given as to why they display a different conformation.
- Bolte, Michael,Bauch, Christian
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Read Online
- Ni-catalyzed reductive decyanation of nitriles with ethanol as the reductant
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A nickel-catalyzed reductive decyanation of aromatic nitriles has been developed, in which the readily available and abundant ethanol was applied as the hydride donor. Various functional groups on the aromatic rings, such as alkoxyl, amino, imino and amide, were compatible in this catalytic protocol. Heteroaryl, benzylic and alkenyl nitriles were also tolerated. Mechanistic investigation indicated that ethanol provided hydride efficientlyviaβ-hydride elimination in this reductive decyanation.
- Wu, Ke,Ling, Yichen,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Jin, Liqun,Hu, Xinquan
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supporting information
p. 2273 - 2276
(2021/03/09)
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- Methylation with Dimethyl Carbonate/Dimethyl Sulfide Mixtures: An Integrated Process without Addition of Acid/Base and Formation of Residual Salts
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Dimethyl sulfide, a major byproduct of the Kraft pulping process, was used as an inexpensive and sustainable catalyst/co-reagent (methyl donor) for various methylations with dimethyl carbonate (as both reagent and solvent), which afforded excellent yields of O-methylated phenols and benzoic acids, and mono-C-methylated arylacetonitriles. Furthermore, these products could be isolated using a remarkably straightforward workup and purification procedure, realized by dimethyl sulfide‘s neutral and distillable nature and the absence of residual salts. The likely mechanisms of these methylations were elucidated using experimental and theoretical methods, which revealed that the key step involves the generation of a highly reactive trimethylsulfonium methylcarbonate intermediate. The phenol methylation process represents a rare example of a Williamson-type reaction that occurs without the addition of a Br?nsted base.
- Chan, Bun,Lui, Matthew Y.,Lui, Yuen Wai
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- Synthesis of Trinuclear Benzimidazole-Fused Hybrid Scaffolds by Transition Metal-Free Tandem C(sp2)?N Bond Formation under Microwave Irradiation
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2-(2-Bromoaryl)- and 2-(2-bromovinyl)benzimidazoles have been coupled and cyclized with 2-methoxy- and 2-aryloxybenzimidazoles as building blocks in the presence of a base under microwave irradiation to give a class of trinuclear N-fused hybrid scaffolds, benzo[4,5]imidazo[1,2-a]benzo[4,5]imidazo[1,2-c]quinazolines and -pyrimidines, respectively, in good yields. 2-(2-Bromoaryl)- and 2-(2-bromovinyl)imidazoles also reacted with 2-methoxybenzimidazoles in the presence of base under microwave irradiation to give a class of trinuclear N-fused hybrid scaffolds, benzo[4,5]imidazo[1,2-a]imidazo[1,2-c]quinazolines and -pyrimidines, respectively, in similar yields. This process seems to proceed via an initial C(sp2)-N coupling by an addition-elimination nucleophilic aromatic substitution (SNAr) and subsequent cyclization accompanied by extrusion of alcohols.
- Dao, Pham Duy Quang,Cho, Chan Sik
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p. 4088 - 4098
(2021/06/16)
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- Trialkylammonium salt degradation: Implications for methylation and cross-coupling
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Trialkylammonium (most notably N,N,N-trimethylanilinium) salts are known to display dual reactivity through both the aryl group and the N-methyl groups. These salts have thus been widely applied in cross-coupling, aryl etherification, fluorine radiolabelling, phase-transfer catalysis, supramolecular recognition, polymer design, and (more recently) methylation. However, their application as electrophilic methylating reagents remains somewhat underexplored, and an understanding of their arylation versus methylation reactivities is lacking. This study presents a mechanistic degradation analysis of N,N,N-trimethylanilinium salts and highlights the implications for synthetic applications of this important class of salts. Kinetic degradation studies, in both solid and solution phases, have delivered insights into the physical and chemical parameters affecting anilinium salt stability. 1H NMR kinetic analysis of salt degradation has evidenced thermal degradation to methyl iodide and the parent aniline, consistent with a closed-shell SN2-centred degradative pathway, and methyl iodide being the key reactive species in applied methylation procedures. Furthermore, the effect of halide and non-nucleophilic counterions on salt degradation has been investigated, along with deuterium isotope and solvent effects. New mechanistic insights have enabled the investigation of the use of trimethylanilinium salts in O-methylation and in improved cross-coupling strategies. Finally, detailed computational studies have helped highlight limitations in the current state-of-the-art of solvation modelling of reaction in which the bulk medium undergoes experimentally observable changes over the reaction timecourse. This journal is
- Assante, Michele,Baillie, Sharon E.,Juba, Vanessa,Leach, Andrew G.,McKinney, David,Reid, Marc,Washington, Jack B.,Yan, Chunhui
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p. 6949 - 6963
(2021/06/02)
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- Ruthenium-Catalyzed Dehydrogenation Through an Intermolecular Hydrogen Atom Transfer Mechanism
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The direct dehydrogenation of alkanes is among the most efficient ways to access valuable alkene products. Although several catalysts have been designed to promote this transformation, they have unfortunately found limited applications in fine chemical synthesis. Here, we report a conceptually novel strategy for the catalytic, intermolecular dehydrogenation of alkanes using a ruthenium catalyst. The combination of a redox-active ligand and a sterically hindered aryl radical intermediate has unleashed this novel strategy. Importantly, mechanistic investigations have been performed to provide a conceptual framework for the further development of this new catalytic dehydrogenation system.
- Huang, Lin,Bismuto, Alessandro,Rath, Simon A.,Trapp, Nils,Morandi, Bill
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supporting information
p. 7290 - 7296
(2021/03/01)
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- A highly stable all-in-one photocatalyst for aryl etherification: The NiIIembedded covalent organic framework
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The efficient conversion of aryl bromides to the corresponding aryl alkyl ethers by dual nickel/photocatalysis has seen great progress, but difficulties of recycling the photosensitizer or nickel complexes cause problems of sustainability. Here, we report the design of a novel, highly stable vinyl bridge 2D covalent organic framework (COF) containing Ni, which combines the role of photosensitizer and reactive site. The as-prepared sp2c-COFdpy-Ni acts as an efficient heterogeneous photocatalyst for C-O cross coupling. The sp2c-COFdpy-Ni can be completely recovered and used repeatedly without loss of activity, overcoming the limitations of the prior methods. Preliminary studies reveal that strong interlayer electron transfer may facilitate the generation of the proposed intermediate sp2c-COFdpy-NiI in a bimolecular and self-sustained manner. This all-in-one heterogeneous photocatalyst exhibits good compatibility of substrates and tolerance of functional groups. The successful attempt to expand the 2D COFs with this new catalyst into photocatalytic organic transformation opens an avenue for photoredox/transition metal mediated coupling reactions.
- Chen, Hao,Dong, Wenbo,Hu, Jianxiang,Rao, Li,Wang, Pei,Wang, Shengyao,Xiang, Yonggang,Yang, Yi
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p. 5797 - 5805
(2021/08/23)
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- Cross-Coupling Reactions of Aryl Halides with Primary and Secondary Aliphatic Alcohols Catalyzed by an O,N,N-Coordinated Nickel Complex
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A synthesis of alkyl aryl ethers was achieved via the cross-coupling of aryl halides with primary and secondary aliphatic alcohols catalyzed by a bench-stable nickel complex supported by a monoanionic O,N,N-tridentate ligand. This nickel-catalyzed reaction proceeds smoothly in the absence of a phosphine ligand, affording alkyl aryl ethers in moderate to good yields. (Figure presented.).
- Hashimoto, Toru,Shiota, Keisuke,Funatsu, Kei,Yamaguchi, Yoshitaka
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supporting information
p. 1625 - 1630
(2021/01/26)
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- Ceramic boron carbonitrides for unlocking organic halides with visible light
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Photochemistry provides a sustainable pathway for organic transformations by inducing radical intermediates from substrates through electron transfer process. However, progress is limited by heterogeneous photocatalysts that are required to be efficient, stable, and inexpensive for long-term operation with easy recyclability and product separation. Here, we report that boron carbonitride (BCN) ceramics are such a system and can reduce organic halides, including (het)aryl and alkyl halides, with visible light irradiation. Cross-coupling of halides to afford new C-H, C-C, and C-S bonds can proceed at ambient reaction conditions. Hydrogen, (het)aryl, and sulfonyl groups were introduced into the arenes and heteroarenes at the designed positions by means of mesolytic C-X (carbon-halogen) bond cleavage in the absence of any metal-based catalysts or ligands. BCN can be used not only for half reactions, like reduction reactions with a sacrificial agent, but also redox reactions through oxidative and reductive interfacial electron transfer. The BCN photocatalyst shows tolerance to different substituents and conserved activity after five recycles. The apparent metal-free system opens new opportunities for a wide range of organic catalysts using light energy and sustainable materials, which are metal-free, inexpensive and stable. This journal is
- Yuan, Tao,Zheng, Meifang,Antonietti, Markus,Wang, Xinchen
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p. 6323 - 6332
(2021/05/19)
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- Reduced Phenalenyl in Catalytic Dehalogenative Deuteration and Hydrodehalogenation of Aryl Halides
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Dehalogenative deuteration reactions are generally performed through metal-mediated processes. This report demonstrates a mild protocol for hydrodehalogenation and dehalogenative deuteration of aryl/heteroaryl halides (39 examples) using a reduced odd alternant hydrocarbon phenalenyl under transition metal-free conditions and has been employed successfully for the incorporation of deuterium in various biologically active compounds. The combined approach of experimental and theoretical studies revealed a single electron transfer-based mechanism.
- Singh, Bhagat,Ahmed, Jasimuddin,Biswas, Amit,Paira, Rupankar,Mandal, Swadhin K.
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supporting information
p. 7242 - 7255
(2021/05/29)
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- Method for reducing aromatic C-N/Cl C/I bond to aromatic-H / D
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A method of reducing C an aromatic-N C/Cl/I bond to an aromatic-H / D, the process being a stable aromatic quaternary ammonium salt. After addition of the base and the solvent, the aromatic compound or the deuterated aromatic compound can be efficiently prepared by irradiation with visible light or ultraviolet light. The method can efficiently convert stable aromatic-N/I chemical bonds into aromatic-H / D bonds by visible light or ultraviolet light in a cheap and easily available solvent or deuterated solvent without using a catalyst or a transition metal compound C C. The whole production process is green, environment-friendly, low in cost, wide in substrate applicability, high in yield, high in deuterated rate, simple and convenient to operate, free of explosion risk and remarkable in advantage compared with the conventional production process.
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Paragraph 0028
(2021/09/08)
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- 2, 3-dihydronaphthalo [2, 3-b] furan-4, 9-diketone compound as well as preparation method and application thereof
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The invention provides a 2, 3-dihydronaphthalo [2, 3-b] furan-4, 9-diketone compound as well as a preparation method and application thereof, and belongs to the technical field of medicines. The invention particularly provides the 2, 3-dihydronaphthalo [2, 3-b] furan-4, 9-diketone compounds shown as general formulas I-A and I-B, a pharmaceutical composition containing the compounds, and a preparation method of the compounds. The compound has STAT3 inhibitory activity and can be used for preparing drugs for treating and/or preventing diseases related to STAT3 activity, and the diseases comprisevarious cancers such as breast cancer, lung cancer, oral cancer, kidney cancer, esophageal cancer, liver cancer, stomach cancer, intestinal cancer, cervical cancer and ovarian cancer.
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Paragraph 0212-0214
(2020/11/05)
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- Enantioselective iron/bisquinolyldiamine ligand‐catalyzed oxidative coupling reaction of 2‐naphthols
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An iron‐catalyzed asymmetric oxidative homo‐coupling of 2‐naphthols for the synthesis of 1,1′‐Bi‐2‐naphthol (BINOL) derivatives is reported. The coupling reaction provides enantioenriched BINOLs in good yields (up to 99%) and moderate enantioselectivities (up to 81:19 er) using an iron‐complex generated in situ from Fe(ClO4)2 and a bisquinolyldiamine ligand [(1R,2R)‐N1,N2‐di(quinolin‐8‐yl)cyclohexane‐1,2‐diamine, L1]. A number of ligands (L2–L8) and the analogs of L1, with various substituents and chiral backbones, were synthesized and examined in the oxidative coupling reactions.
- Liu, Wen-Bo,Usman, Muhammad,Wu, Lin-Yang
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- PYRIDONE-PYRIMIDINE DERIVATIVE ACTING AS KRASG12C MUTEIN INHIBITOR
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Provided are a class of KRAS G12C mutein inhibitors, which relate in particular to a compound represented by formula (I), an isomer thereof, and a pharmaceutically acceptable salt thereof.
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Paragraph 0276-0277
(2020/12/07)
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- Catalytic Reductions Without External Hydrogen Gas: Broad Scope Hydrogenations with Tetrahydroxydiboron and a Tertiary Amine
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Facile reduction of aryl halides with a combination of 5% Pd/C, B2(OH)4, and 4-methylmorpholine is reported. Aryl bromides, iodides, and chlorides were efficiently reduced. Aryl dihalides containing two different halogen atoms underwent selective reduction: I over Br and Cl, and Br over Cl. Beyond these, aryl triflates were efficiently reduced. This combination was broadly general, effectuating reductions of benzylic halides and ethers, alkenes, alkynes, aldehydes, and azides, as well as for N-Cbz deprotection. A cyano group was unaffected, but a nitro group and a ketone underwent reduction to a low extent. When B2(OD)4 was used for aryl halide reduction, a significant amount of deuteriation occurred. However, H atom incorporation competed and increased in slower reactions. 4-Methylmorpholine was identified as a possible source of H atoms in this, but a combination of only 4-methylmorpholine and Pd/C did not result in reduction. Hydrogen gas has been observed to form with this reagent combination. Experiments aimed at understanding the chemistry led to the proposal of a plausible mechanism and to the identification of N,N-bis(methyl-d3)pyridin-4-amine (DMAP-d6) and B2(OD)4 as an effective combination for full aromatic deuteriation. (Figure presented.).
- Korvinson, Kirill A.,Akula, Hari K.,Malinchak, Casina T.,Sebastian, Dellamol,Wei, Wei,Khandaker, Tashrique A.,Andrzejewska, Magdalena R.,Zajc, Barbara,Lakshman, Mahesh K.
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supporting information
p. 166 - 176
(2020/01/02)
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- Exploiting the radical reactivity of diazaphosphinanes in hydrodehalogenations and cascade cyclizations
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The remarkable reducibility of diazaphosphinanes has been extensively applied in various hydrogenations, based on and yet limited by their well-known hydridic reactivity. Here we exploited their unprecedented radical reactivity to implement hydrodehalogenations and cascade cyclizations originally inaccessible by hydride transfer. These reactions feature a broad substrate scope, high efficiency and simplicity of manipulation. Mechanistic studies suggested a radical chain process in which a phosphinyl radical is generated in a catalytic cycle via hydrogen-atom transfer from diazaphosphinanes. The radical reactivity of diazaphosphinanes disclosed here differs from their well-established hydridic reactivity, and hence, opens a new avenue for diazaphosphinane applications in organic syntheses.
- Cheng, Jin-Pei,Yang, Jin-Dong,Zhang, Jingjing
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p. 4786 - 4790
(2020/06/18)
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- Arenium cation or radical cation? An insight into the cyclodehydrogenation reaction of 2-substituted binaphthyls mediated by Lewis acids
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Perylene and its derivatives are some of the most interesting chromophores in the field of molecular design. One of the most employed methodologies for their synthesis is the cyclodehydrogenation of binaphthyls mediated by Lewis acids. In this article, we investigated the cyclodehydrogenation reaction of 2-substituted binaphthyls to afford thebay-substituted perylene. By using AlCl3as a Lewis acid and high temperatures (the Scholl reaction), two new products bearing NH2and N(CH3)2groups at position 2 of the perylene ring were synthesized. Under these conditions, we were also able to obtain terrylene from ternaphthalene in 38percent yield after two cyclodehydrogenation reactions in a single step. The attempts to promote the formation of a radical cation (necessary intermediary for the oxidative aromatic coupling mechanism) by using FeCl3or a strong oxidant like 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) did not yield the expected products. DFT calculations suggested that the lack of reaction for oxidative aromatic coupling is caused by the difference between the oxidation potentials of the donor/acceptor couple. In the case of the Scholl reaction, the regiochemistry involved in the formation of the σ-complex together with the activation energy of the C-C coupling reaction helped to explain the differences in the reactivity of the different substrates studied.
- Baumgartner, María T.,Camargo Solórzano, Patricia,Jimenez, Liliana B.,Puiatti, Marcelo
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p. 21974 - 21985
(2020/07/03)
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- Selective Methylation of Amides, N-Heterocycles, Thiols, and Alcohols with Tetramethylammonium Fluoride
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We herein disclose the use of tetramethylammonium fluoride (TMAF) as a direct and selective methylating agent of a variety of amides, indoles, pyrroles, imidazoles, alcohols, and thiols. The method is characterized by operational simplicity, wide scope, and ease of purification. Our computational studies suggest a concerted methylation-deprotonation as the preferred reaction pathway.
- Cheng, Hong-Gang,Pu, Maoping,Kundu, Gourab,Schoenebeck, Franziska
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supporting information
p. 331 - 334
(2019/12/30)
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- Iodine(III)-Mediated, Controlled Di- or Monoiodination of Phenols
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An oxidative procedure for the electrophilic iodination of phenols was developed by using iodosylbenzene as a nontoxic iodine(III)-based oxidant and ammonium iodide as a cheap iodine atom source. A totally controlled monoiodination was achieved by buffering the reaction medium with K3PO4. This protocol proceeds with short reaction times, at mild temperatures, in an open flask, and generally with high yields. Gram-scale reactions, as well as the scope of this protocol, were explored with electron-rich and electron-poor phenols as well as heterocycles. Quantum chemistry calculations revealed PhII(OH)·NH3 to be the most plausible iodinating active species as a reactive "I+" synthon. In light of the relevance of the iodoarene moiety, we present herein a practical, efficient, and simple procedure with a broad functional group scope that allows access to the iodoarene core unit.
- Satkar, Yuvraj,Yera-Ledesma, Luisa F.,Mali, Narendra,Patil, Dipak,Segura-Quezada, Luis A.,Ramírez-Morales, Perla I.,Solorio-Alvarado, César R.,Navarro-Santos, Pedro
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p. 4149 - 4164
(2019/04/30)
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- C-H Nickelation of Naphthyl Phosphinites: Electronic and Steric Limitations, Regioselectivity, and Tandem C-P Functionalization
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This report describes the results of a study on the C-H nickelation of phosphinites derived from variously substituted 1- and 2-naphthols, as well as the C-P functionalization of the Ni-naphthyl moiety arising from the C-H cyclonickelation. Refluxing 4-X-1-naphthyl phosphinites (X = H, 1a; MeO, 1b; Cl, 1c) with {(i-PrCN)NiBr2}n and Et3N in acetonitrile gave the nickelacyclic complexes {(κP,κC-4-X-1-OP(i-Pr)2-naphth-2-yl)Ni(μ-Br)}2, 2a-c, resulting from cyclonickelation at the C2-H, whereas cyclonickelation of the 2-naphthyl phosphinite analogue 1e under the same conditions occurred at C3-H. Placing a Me substituent at the C3 position of a 2-naphthyl phosphinite (1f) led to a very sluggish nickelation at the C1-H position, whereas 2-ethyl-1-naphthyl phosphinite (1d) failed to nickelate at C8-H. H/D scrambling tests conducted on the deuterated analogue of 1a (1a-d7) confirmed that nickelation occurs exclusively at C2. Similar tests conducted on deuterated analogues of alkyl-substituted 1- and 2-naphthyl phosphinites showed that no nickelation takes place at Csp3-H sites of the alkyl substituents. In contrast, very facile C-H nickelation was observed with 2-allyl-1-naphthyl phosphinite 1g to give a product featuring a π-allyl-Ni moiety. A series of tests have shown that the nickelation of substrates 1a, 1e, and 1f can be accelerated dramatically at 120-160 °C. On the other hand, conducting the high temperature reaction of 1a in the absence of Et3N resulted in an unanticipated and interesting C-P functionalization of the C2-H site, thus generating a i-Pr2P-substituted bidentate phosphine-phosphinite. A similar tandem C-H nickelation/C-P(O) functionalization was also observed at the C8-H position of substrate 1d. The mechanisms of these functionalization reactions have been probed and outlined.
- Mangin, Lo?c P.,Zargarian, Davit
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supporting information
p. 4687 - 4700
(2019/12/24)
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- Synthesis method of D,L-naproxen
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The invention provides a synthesis method of D,L-naproxen. The synthesis method is characterized by comprising the step of removing bromine: taking D,L-2-(5-bromo-6-methoxyl-naphthyl)-sodium propionate as a raw material, and taking water and dioxane as solvents, adding a catalyst under alkaline conditions and nitrogen protection, reacting under 80-90 DEG C, filtering after the reaction is completed, and regulating the pH (Potential of hydrogen) of filtrate by acid to obtain a final product, wherein the catalyst is one of tetrakis(triphenylphosphine)palladium or diacetatobis(triphenylphosphine)palladium(II) or palladium chloride taking triphenylphosphine as a ligand. According to the synthesis method, through optimizing the synthesis method of naproxen, the tetrakis(triphenylphosphine)palladium and the diacetatobis(triphenylphosphine) palladium(II) as well as the palladium chloride taking the triphenylphosphine as the ligand are adopted as the catalyst to remove the bromine on a benzene ring; hydrogenation and high pressure are not needed; the reaction is safe and reliable; the yield is high; the synthesis method is suitable for industrial production.
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Paragraph 0043-0046
(2019/10/01)
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- On/Off O2 Switchable Photocatalytic Oxidative and Protodecarboxylation of Carboxylic Acids
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Photoredox catalysis in recent years has manifested a powerful branch of science in organic synthesis. Although merging photoredox and metal catalysts has been a widely used method, switchable heterogeneous photoredox catalysis has rarely been considered. Herein, we open a new window to use a switchable heterogeneous photoredox catalyst which could be turned on/off by changing a simple stimulus (O2) for two opponent reactions, namely, oxidative and protodecarboxylation. Using this strategy, we demonstrate that Au@ZnO core-shell nanoparticles could be used as a switchable photocatalyst which has good catalytic activity to absorb visible light due to the localized surface plasmon resonance effect of gold, can decarboxylate a wide range of aromatic and aliphatic carboxylic acids, have multiple reusability, and are a reasonable candidate for synthesizing both aldehydes/ketones and alkane/arenes in a large-scale set up. Some biologically active molecules are also shown via examples of the direct oxidative and protodecarboxylation which widely provided pharmaceutical agents.
- Bazyar, Zahra,Hosseini-Sarvari, Mona
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p. 13503 - 13515
(2019/10/11)
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- Practical heterogeneous photoredox/nickel dual catalysis for C-N and C-O coupling reactions
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Efficient C-N and C-O coupling reactions of aryl halides with amines and alcohols have been developed by using the strategy of heterogeneous visible light photoredox and nickel dual catalysis. Obviously, the joint use of inexpensive and bench-stable CdS and nickel salts, together with mild reaction conditions, makes these two transformations attractive for the synthetic community. This heterogeneous dual catalysis system also proved to be successful in the ligand-free catalytic hydroxylation of aryl bromide with water as a nucleophile. The practicality of this protocol is further emphasized by the scaled-up reaction and the reusability of heterogeneous photocatalysts.
- Liu, Yi-Yin,Liang, Dong,Lu, Liang-Qiu,Xiao, Wen-Jing
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supporting information
p. 4853 - 4856
(2019/05/02)
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- Sodium Butylated Hydroxytoluene (NaBHT) as a New and Efficient Hydride Source for Pd-Catalysed Reduction Reactions
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NaBHT (sodium butylated hydroxytoluene), a hindered and soluble base for the efficient arylation of various base-sensitive amines and (hetero)aryl halides has been found to have an unanticipated role as a hydride donor to reduce (hetero)aryl halides and allylic acetates. Mechanistic studies have uncovered that NaBHT, but not BHT, can deliver multiple hydrides through oxidation of the benzylic methyl group in NaBHT to the aldehyde. Further, performing the reduction with NaBHT-d20 has revealed that the redox-active benzylic position is not the only hydride donor site from NaBHT with one hydride in three coming, presumably, from the tert-butyl groups. The reduction works well under mild conditions and, incredibly, only consumes 20 percent of the NaBHT in the process; the remaining 80 percent can be readily recovered in pure form and reused. This, combined with the low cost of the material in ton-scale quantity, makes it practical and attractive for wider use in industry at scale.
- Sharif, Sepideh,Rodriguez, Michael J.,Lu, Yu,Kopach, Michael E.,Mitchell, David,Hunter, Howard N.,Organ, Michael G.
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supporting information
p. 13099 - 13103
(2019/10/28)
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- Hydrodehalogenation of Aryl Halides through Direct Electrolysis
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A catalyst- and metal-free electrochemical hydrodehalogenation of aryl halides is disclosed. Our reaction by a flexible protocol is operated in an undivided cell equipped with an inexpensive graphite rod anode and cathode. Trialkylamines nBu3N/Et3N behave as effective reductants and hydrogen atom donors for this electrochemical reductive reaction. Various aryl and heteroaryl bromides worked effectively. The typically less reactive aryl chlorides and fluorides can also be smoothly converted. The utility of our method is demonstrated by detoxification of harmful pesticides and hydrodebromination of a dibrominated biphenyl (analogues of flame-retardants) in gram scale.
- Ke, Jie,Wang, Hongling,Zhou, Liejin,Mou, Chengli,Zhang, Jingjie,Pan, Lutai,Chi, Yonggui Robin
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supporting information
p. 6911 - 6914
(2019/05/10)
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- Acid-Catalyzed Versus Thermally Induced C1-C1′ Bond Cleavage in 1,1′-Bi-2-naphthol: An Experimental and Theoretical Study
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Experiments show that 1,1′-bi-2-naphthol (BINOL) undergoes facile C1-C1′ bond cleavage under action of triflic acid at temperatures above 0 °C to give mainly 2-naphthol along with oligomeric material. CASSCF and MRMP//CASSCF computations have demonstrated unambiguously that this unusual mode of scission of the biaryl bond can occur in the C1,C1′-diprotonated form of BINOL via a mechanism involving homolytic cleavage prompted by the intramolecular electrostatic repulsion. These findings also provide insights into the mechanism of a comparatively easy thermal cleavage of BINOL, implying the intermediacy of its neutral diketo form.
- Genaev, Alexander M.,Shchegoleva, Lyudmila N.,Salnikov, George E.,Shernyukov, Andrey V.,Shundrin, Leonid A.,Shundrina, Inna K.,Zhu, Zhongwei,Koltunov, Konstantin Yu.
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p. 7238 - 7243
(2019/06/14)
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- Highly-chemoselective step-down reduction of carboxylic acids to aromatic hydrocarbons: Via palladium catalysis
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Aryl carboxylic acids are among the most abundant substrates in chemical synthesis and represent a perfect example of a traceless directing group that is central to many processes in the preparation of pharmaceuticals, natural products and polymers. Herein, we describe a highly selective method for the direct step-down reduction of carboxylic acids to arenes, proceeding via well-defined Pd(0)/(ii) catalytic cycle. The method shows a remarkably broad substrate scope, enabling to direct the classical acyl reduction towards selective decarbonylation by a redox-neutral mechanism. The utility of this reaction is highlighted in the direct defunctionalization of pharmaceuticals and natural products, and further emphasized in a range of traceless processes using removable carboxylic acids under mild, redox-neutral conditions orthogonal to protodecarboxylation. Extensive DFT computations were conducted to demonstrate preferred selectivity for the reversible oxidative addition and indicated that a versatile hydrogen atom transfer (HAT) pathway is operable.
- Liu, Chengwei,Qin, Zhi-Xin,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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p. 5736 - 5742
(2019/06/18)
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- Cross-Coupling of Chloro(hetero)arenes with Thiolates Employing a Ni(0)-Precatalyst
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A general and efficient Ni-catalyzed coupling of challenging aryl chlorides and in situ generated aliphatic and aromatic thiolates is described. The employed on-cycle, air-stable defined Ni precatalysts allow for transformation of a broad scope of substrates. A variety of functional groups and heterocyclic motifs as well as structurally varied thiols are tolerated at unprecedented moderate catalyst loadings and reaction temperatures. Depending on reaction conditions, aryl thiols can selectively undergo C-S or C-C couplings.
- Gehrtz, Paul H.,Geiger, Valentin,Schmidt, Tanno,Sr?an, Laura,Fleischer, Ivana
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supporting information
p. 50 - 55
(2019/01/11)
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- NITROGEN-CONTAINING BIOPOLYMER-BASED CATALYSTS, THEIR PREPARATION AND USES IN HYDROGENATION PROCESSES, REDUCTIVE DEHALOGENATION AND OXIDATION
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The present invention relates to a process for the preparation of a nitrogen containing biopolymer-based catalyst by pyrolysis of a metal complex with a nitrogen-containing biopolymer and to the nitrogen containing biopolymer-based catalysts obtainable by this process. In particular, the invention relates to a nitrogen containing biopolymer-based catalyst comprising metal particles and at least one nitrogen containing carbon layer. The invention also relates to the use of a nitrogen containing biopolymer-based catalyst in a hydrogenation process, preferably in a process for hydrogenation of nitroarenes, nitriles or imines; in a reductive dehalogenation process of C-X bonds, wherein X is CI, Br or I, preferably in a process for dehalogenation of organohalides or in a process for deuterium labelling of arenes via dehalogenation of organohalides; or in an oxidation process. Further, the invention relates to a metal complex with the nitrogen containing biopolymer, wherein the metal is a transition metal selected from the group consisting of manganese, ruthenium, cobalt, rhodium, nickel, palladium and platinum, preferably cobalt or nickel, and wherein the nitrogen containing biopolymer is selected from chitosan, chitin and a polyamino acid, preferably chitosan or chitin.
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Page/Page column 18-19
(2018/07/29)
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- From Anilines to Aryl Ethers: A Facile, Efficient, and Versatile Synthetic Method Employing Mild Conditions
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We have developed a simple and direct method for the synthesis of aryl ethers by reacting alcohols/phenols (ROH) with aryl ammonium salts (ArNMe3+), which are readily prepared from anilines (ArNR′2, R′=H or Me). This reaction proceeds smoothly and rapidly (within a few hours) at room temperature in the presence of a commercially available base, such as KOtBu or KHMDS, and has a broad substrate scope with respect to both ROH and ArNR′2. It is scalable and compatible with a wide range of functional groups.
- Wang, Dong-Yu,Yang, Ze-Kun,Wang, Chao,Zhang, Ao,Uchiyama, Masanobu
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supporting information
p. 3641 - 3645
(2018/03/13)
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- Method for hydrogenation reduction of organic halide by semiconductor photocatalysis
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The invention discloses a method for hydrogenation reduction of organic halide by semiconductor photocatalysis. Semiconductor materials boron, nitrogen and carbon serve as photocatalysts, and the organic halide C-X (X=Br and Cl) is hydrogenated and reduced into a dehalogenated compound. The boron, nitrogen and carbon are used for hydrogenating and reducing the organic halide, the reaction processis simple in operation, catalysis effects are good, catalysis can be performed in visible light, conditions are mild, and the method is low in cost, meets practical production requirements and has a large application potential.
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Paragraph 0018
(2018/09/13)
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- Air-Stable Blue Phosphorescent Tetradentate Platinum(II) Complexes as Strong Photo-Reductant
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Strong photo-reductants have applications in photo-redox organic synthesis involving reductive activation of C?X(halide) and C=O bonds. We report herein air-stable PtII complexes supported by tetradentate bis(phenolate-NHC) ligands having peripheral electron-donating N-carbazolyl groups. Photo-physical, electrochemical, and computational studies reveal that the presence of N-carbazolyl groups enhances the light absorption and redox reversibility because of its involvement into the frontier MOs in both ground and excited states, making the complexes robust strong photo-reductant with E([Pt]+/*) over ?2.6 V vs. Cp2Fe+/0. The one-electron reduced [Pt]? species are stronger reductants with EPC([Pt]0/?) up to ?3.1 V vs. Cp2Fe+/0. By virtue of the strong reducing nature of these species generated upon light excitation, they can be used in light-driven reductive coupling of carbonyl compounds and reductive debromination of a wide range of unactivated aryl bromides.
- Li, Kai,Wan, Qingyun,Yang, Chen,Chang, Xiao-Yong,Low, Kam-Hung,Che, Chi-Ming
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supporting information
p. 14129 - 14133
(2018/10/15)
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- Method for synthesizing alkyl-2-naphthyl ether
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The invention discloses a method for synthesizing alkyl-2-naphthyl ether. 2-naphthol, a catalyst and dialkyl carbonate are heated to 110-120 DEG C, dialkyl carbonate is added dropwise, a mixed solution of dialkyl carbonate and corresponding alcohol is fractionated out during dropwise addition, the temperature is controlled not to exceed 200 DEG C, reaction is stopped when conversion of 2-naphtholreaches 95% or higher, inorganic boric acid and a dehydration solvent are added, unreacted 2-naphthol is removed, and rectification or recrystallization is performed, and a pure product is obtained. The process route has little corrosion to equipment, few 'three wastes' emissions and low environmental pollution.
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Paragraph 0015; 0019
(2019/01/14)
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- NAPHTHALENE-CONTAINING POLYMERS AND METHODS OF MAKING THE SAME
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The present disclosure relates to a dimer that includes a first hydroxyl-functionalized naphthalene group and a second hydroxyl-functionalized naphthalene group, where the first hydroxyl-functionalized naphthalene group and the second hydroxyl-functionalized naphthalene group are connected by a bridging group. The present disclosure also relates to a polymer synthesized using the dimer, as well as methods for synthesizing both the dimer and the polymer.
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Paragraph 0023; 0089-0095
(2018/08/09)
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- Efficient and selective hydrogenation of C-O bonds with a simple sodium formate catalyzed by nickel
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A Ni-catalyzed hydrogenation of C-O compounds with sodium formate is developed. Various esters, i.e. aryl, alkenyl, benzyl pivalates, and even the aryl ethers, were efficiently reduced with a loading of nickel catalysts down to 0.5 mol%. Reactive functional groups such as C-C double bonds, carbonyl, CN, MeS and halogen groups are tolerable. This reaction can be used for the modification of complex molecules and carried out at a large scale.
- Xi, Xiaoxiang,Chen, Tieqiao,Zhang, Ji-Shu,Han, Li-Biao
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p. 1521 - 1524
(2018/02/19)
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- Synthesis of pharmacologically important naphthoquinones and anticancer activity of 2-benzyllawsone through DNA topoisomerase-II inhibition
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Naphthoquinones are naturally occurring biologically active entities. Practical de novo syntheses of three naphthoquinones i.e. lawsone (1), lapachol (2), and β-lapachone (3b) have been achieved from commercially available starting materials. The conversion of lapachol (2) to β-lapachone (3b) was achieved through p-TSA/Iodine/BF3-etherate mediated regioselective cyclisation. Further, 2-alkyl and 2-benzyllawsone derivatives have been prepared as possible anticancer agents. Four derivatives exhibited significant anticancer activity and the best analogue i.e. compound 21a exhibited potential anticancer activity (IC50?=?5.2?μM) against FaDu cell line. Compound 21a induced apoptosis through activation of caspase pathway and exerted cell cycle arrest at S phase in FaDU cells. It also exhibited significant topoisomerase-II inhibition activity. Compound 21a was found to be safe in Swiss albino mice up to 1000?mg/kg oral dose.
- Kumar, Balagani Sathish,Ravi, Kusumoori,Verma, Amit Kumar,Fatima, Kaneez,Hasanain, Mohammad,Singh, Arjun,Sarkar, Jayanta,Luqman, Suaib,Chanda, Debabrata,Negi, Arvind S.
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p. 1364 - 1373
(2017/02/18)
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- Construction of Condensed Polycyclic Aromatic Frameworks through Intramolecular Cycloaddition Reactions Involving Arynes Bearing an Internal Alkyne Moiety
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Facile synthetic methods for condensed polycyclic aromatic compounds via aryne intermediates are reported. The generation of arynes bearing a (3-arylpropargyl)oxy group from the corresponding o-iodoaryl triflate-type precursors efficiently afforded arene-fused oxaacenaphthene derivatives, which were formed through intramolecular [2+4] cycloaddition. Extending the method to the generation of arynes bearing a 1,3-diyne moiety led to a continuous generation of naphthalyne intermediate through the hexadehydro Diels–Alder reaction involving the aryne triple bond. This novel type of aryne-relay chemistry enabled the synthesis of a unique aminoarylated oxaacenaphthene derivative and highly ring-fused anthracene derivatives.
- Yoshida, Suguru,Shimizu, Keita,Uchida, Keisuke,Hazama, Yuki,Igawa, Kazunobu,Tomooka, Katsuhiko,Hosoya, Takamitsu
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supporting information
p. 15332 - 15335
(2017/10/18)
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- Method for continuous preparation of β - naphthyl methyl ether process method (by machine translation)
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The invention discloses a method for continuous preparation of β - naphthyl methyl ether of the process method, comprising the following steps: taking certain proportion of methanol and naphthol as raw materials, organic acid As the catalyst, administered by the catalytic reaction of the type gas phase, then decompressing and rectification, to obtain the β - naphthyl methyl ether. Compared with the prior art, the process of the invention can be continuous operation, naphthol conversion is 99% or more, selectively reaches 98% or more, by the decompression side stream refining, β - naphthyl methyl ether the purity of 98% or more, organic acid After 120 hours of continuous use, naphthol conversion rate only reduce 0.13% the left and the right, overcomes the inorganic acid catalytic production process the solid dust and form the waste acid saline and other problems. (by machine translation)
- -
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Paragraph 0013-0031
(2017/07/19)
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- Selective Reductive Removal of Ester and Amide Groups from Arenes and Heteroarenes through Nickel-Catalyzed C?O and C?N Bond Activation
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An inexpensive nickel(II) catalyst and a hydrosilane were used for the efficient reductive defunctionalization of aryl and heteroaryl esters through a decarbonylative pathway. This versatile method could be used for the removal of ester and amide functional groups from various organic molecules. Moreover, a scale-up experiment and a synthetic application based on the use of a removable carboxylic acid directing group highlight the usefulness of this reaction.
- Yue, Huifeng,Guo, Lin,Lee, Shao-Chi,Liu, Xiangqian,Rueping, Magnus
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supporting information
p. 3972 - 3976
(2017/03/27)
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- Hydrodehalogenation of Haloarenes by a Sodium Hydride–Iodide Composite
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A simple protocol for hydrodebromination and -deiodination of halo(hetero)arenes was enabled by sodium hydride (NaH) in the presence of lithium iodide (LiI). Mechanistic studies showed that an unusual concerted nucleophilic aromatic substitution operates in the present process.
- Ong, Derek Yiren,Tejo, Ciputra,Xu, Kai,Hirao, Hajime,Chiba, Shunsuke
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supporting information
p. 1840 - 1844
(2017/02/05)
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- Catalytic Behaviour of Calixarenylphosphanes in Nickel-Catalysed Suzuki–Miyaura Cross-Coupling
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Two upper-rim-functionalised calix[4]arenes, 5-diphenylphosphino-25,26,27,28-tetra-benzyloxycalix[4]arene and 5-diphenylphosphino-25,26,27,28-tetra-(p-anisyl)methyloxy calix[4]arene, were investigated in the nickel-catalysed cross-coupling of phenylboronic acid with aryl bromides. The catalytic activities are higher than those observed for other triarylphosphanes, notably PPh3and P(o-tolyl)3as well as the Buchwald-type ligand o-biph-PPh2[TOFs up to 2600 mol(ArPh) mol(Ni)–1h–1], but the production of large amounts of dehalogenation product could not be avoided, thus strongly contrasting with the classical Pd-catalysed reaction. Good activities were also obtained with aryl chlorides, even at room temperature. The higher efficiency of 1 and 2 relative to that of the Buchwald ligand 3 probably arises from the ease with which these two calix–phosphanes may form appropriate monophosphine complexes before the oxidative addition step.
- Monnereau, Laure,Sémeril, David,Matt, Dominique,Gourlaouen, Christophe
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p. 581 - 586
(2017/02/05)
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- A Biomass-Derived Non-Noble Cobalt Catalyst for Selective Hydrodehalogenation of Alkyl and (Hetero)Aryl Halides
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Hydrodehalogenation is a straightforward approach for detoxifications of harmful anthropogenic organohalide-based pollutants, as well as removal of halide protecting groups used in multistep syntheses. A novel sustainable catalytic material was prepared from biowaste (chitosan) in combination with an earth-abundant cobalt salt. The heterogeneous catalyst was fully characterized by transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy measurements, and successfully applied to hydrodehalogenation of alkyl and (hetero)aryl halides with broad scope (>40 examples) and excellent chemoselectivity using molecular hydrogen as a reductant. The general usefulness of this method is demonstrated by successful detoxification of non-degradable pesticides and fire retardants. Moreover, the potential of the catalyst as a deprotection tool is demonstrated in a multistep synthesis of (±)-peronatin B (alkaloid).
- Sahoo, Basudev,Surkus, Annette-Enrica,Pohl, Marga-Martina,Radnik, J?rg,Schneider, Matthias,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
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supporting information
p. 11242 - 11247
(2017/09/02)
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- Radical Hydrodehalogenation of Aryl Bromides and Chlorides with Sodium Hydride and 1,4-Dioxane
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A practical method for radical chain reduction of various aryl bromides and chlorides is introduced. The thermal process uses NaH and 1,4-dioxane as reagents and 1,10-phenanthroline as an initiator. Hydrodehalogenation can be combined with typical cyclization reactions, proving the nature of the radical mechanism. These chain reactions proceed by electron catalysis. DFT calculations and mechanistic studies support the suggested mechanism.
- Hokamp, Tobias,Dewanji, Abhishek,Lübbesmeyer, Maximilian,Mück-Lichtenfeld, Christian,Würthwein, Ernst-Ulrich,Studer, Armido
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supporting information
p. 13275 - 13278
(2017/10/09)
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- A Dual Palladium and Copper Hydride Catalyzed Approach for Alkyl–Aryl Cross-Coupling of Aryl Halides and Olefins
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We report an efficient means of sp2–sp3 cross coupling for a variety of terminal monosubstituted olefins with aryl electrophiles using Pd and CuH catalysis. In addition to its applicability to a range of aryl bromide substrates, this process was also suitable for electron-deficient aryl chlorides, furnishing higher yields than the corresponding aryl bromides in these cases. The optimized protocol does not require the use of a glovebox and employs air-stable Cu and Pd complexes as precatalysts. A reaction on 10 mmol scale further highlighted the practical utility of this protocol. Employing a similar protocol, a series of cyclic alkenes were also examined. Cyclopentene was shown to undergo efficient coupling under these conditions. Lastly, deuterium-labeling studies indicate that deuterium scrambling does not take place in this sp2-sp3 cross coupling, implying that β-hydride elimination is not a significant process in this transformation.
- Friis, Stig D.,Pirnot, Michael T.,Dupuis, Lauren N.,Buchwald, Stephen L.
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supporting information
p. 7242 - 7246
(2017/06/13)
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- Masked N-Heterocyclic Carbene-Catalyzed Alkylation of Phenols with Organic Carbonates
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An easily prepared masked N-heterocyclic carbene, 1,3-dimethylimidazolium-2-carboxylate (DMI-CO2), was investigated as a “green” and inexpensive organocatalyst for the alkylation of phenols. The process made use of various low-toxicity and renewable alkylating agents, such as dimethyl- and diethyl carbonate, in a focused microwave reactor. DMI-CO2 was found to be a very active catalyst and excellent yields of a range of aryl alkyl ethers were obtained under relatively benign conditions. The observed difference in the conversion behavior of phenol methylation, in the presence of either the carbene or 1,8-diazabicycloundec-7-ene (DBU) catalyst, was rationalized on the basis of mechanistic investigations. The primary mode of action for the N-heterocyclic carbene is nucleophilic catalysis. Activation of the dialkyl carbonate electrophile results in concomitant evolution of an organo-soluble alkoxide, which deprotonates the phenolic starting material. In contrast, DBU is initially protonated by the phenol and thus consumed. Subsequent regeneration and participation in nucleophilic catalysis only becomes significant after some phenolate alkylation occurs.
- Lui, Matthew Y.,Yuen, Alexander K. L.,Masters, Anthony F.,Maschmeyer, Thomas
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p. 2312 - 2316
(2016/10/24)
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- Coumarin derivative, and preparation method and use thereof
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The invention relates to a coumarin derivative and a use thereof. The coumarin derivative is a compound represented by formula I. The compound represented by formula I can be applied as an organic pigment. The application field of the coumarin derivative with a large pi conjugated system is developed, and foundation is laid for commercial preparation of like coumarin derivatives. In the formula I, R1-R7 are respectively independently selected from hydrogen, halogens, C1-C4 linear or branched alkyl groups, fluorine-containing C1-C4 linear or branched alkyl groups, hydroxyl groups, C1-C3 linear or branched alkyloxy groups, trifluoromethylsulfo groups or C6-C10 aryl groups; or R1, R4, R5, R6 and R7 are respectively independently selected from one of H and C1-C3 linear or branched alkyl groups, and a combination of R2 and R3 is a bivalent phenyl group.
- -
-
Paragraph 0092; 0093
(2016/10/09)
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- Nickel-Catalyzed Alkoxy–Alkyl Interconversion with Alkylborane Reagents through C?O Bond Activation of Aryl and Enol Ethers
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A nickel-catalyzed alkylation of polycyclic aromatic methyl ethers as well as methyl enol ethers with B-alkyl 9-BBN and trialkylborane reagents that involves the cleavage of stable C(sp2)?OMe bonds is described. The transformation has a wide substrate scope and good chemoselectivity profile while proceeding under mild reaction conditions; it provides a versatile way to form C(sp2)?C(sp3) bonds that does not suffer from β-hydride elimination. Furthermore, a selective and sequential alkylation process by cleavage of inert C?O bonds is presented to demonstrate the advantage of this method.
- Guo, Lin,Liu, Xiangqian,Baumann, Christoph,Rueping, Magnus
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supporting information
p. 15415 - 15419
(2016/12/03)
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- Palladium Nanoparticles Supported on Fibrous Silica (KCC-1-PEI/Pd): A Sustainable Nanocatalyst for Decarbonylation Reactions
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A practical and convenient decarbonylation of a variety of aromatic, heteroaromatic, and alkenyl aldehydes by using palladium nanoparticles supported on novel, fibrous nanosilica, named KCC-1-PEI/Pd, has been developed. Complete conversion of aldehyde functionalities into deformylated products was achieved in all cases and in nearly all cycles tested by reusing the catalyst systems. This method eliminates further purification of products after their isolation. Syntheses of at least three different deformylated products have been shown in sequence with the same catalyst system, which neither requires use of any additives, such as oxidants and bases, nor CO scavengers.
- Kundu, Pintu K.,Dhiman, Mahak,Modak, Atanu,Chowdhury, Arindam,Polshettiwar, Vivek,Maiti, Debabrata
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p. 1142 - 1146
(2016/11/23)
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- Shifting Chemical Equilibria in Flow - Efficient Decarbonylation Driven by Annular Flow Regimes
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To efficiently drive chemical reactions, it is often necessary to influence an equilibrium by removing one or more components from the reaction space. Such manipulation is straightforward in open systems, for example, by distillation of a volatile product from the reaction mixture. Herein we describe a unique high-temperature/high-pressure gas/liquid continuous-flow process for the rhodium-catalyzed decarbonylation of aldehydes. The carbon monoxide released during the reaction is carried with a stream of an inert gas through the center of the tubing, whereas the liquid feed travels as an annular film along the wall of the channel. As a consequence, carbon monoxide is effectively vaporized from the liquid phase into the gas phase and stripped from the reaction mixture, thus driving the equilibrium to the product and preventing poisoning of the catalyst. This approach enables the catalytic decarbonylation of a variety of aldehydes with unprecedented efficiency with a standard coil-based flow device.
- Gutmann, Bernhard,Elsner, Petteri,Glasnov, Toma,Roberge, Dominique M.,Kappe, C. Oliver
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supporting information
p. 11557 - 11561
(2016/02/19)
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- Methylation of phenol and its derivatives with dimethyl carbonate in the presence of Mn2(CO)10, W(CO)6, and Co2(CO)8
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Aryl methyl ethers were synthesized by reactions of phenol, substituted phenols, and α- and β-naphthols with dimethyl carbonate in the presence of manganese, tungsten, and cobalt carbonyls. Optimal reactant and catalyst ratios and reaction conditions were found to ensure selective formation of aryl methyl ethers.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
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p. 330 - 334
(2015/05/04)
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