- Continuous Flow Asymmetric Hydrogenation with Supported Ionic Liquid Phase Catalysts Using Modified CO2 as the Mobile Phase: From Model Substrate to an Active Pharmaceutical Ingredient
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The continuous flow asymmetric hydrogenation of (hetero)aromatic enamides has been realized using a Rh-Quinaphos catalyst immobilized in a supported ionic liquid phase (SILP) and employing supercritical CO2 modified with toluene (modCO2) as the mobile phase. This approach allows expansion of the scope of the original SILP/scCO2 system to nonvolatile substrates with poor solubility in pure CO2. The potential of a SILP catalyst in combination with modCO2 was demonstrated for an industrial case study using the continuous flow hydrogenation for the synthesis of a key intermediate of an active pharmaceutical ingredient (API) from AstraZeneca's portfolio. Toluene was selected as the most promising modifier, and the influence of the ratio of modifier to CO2 was evaluated in detail. The catalyst support was found to play a major role for maintaining constant performance and the use of hydrophobic fluorous reverse-phase silica (FRP-SiO2) instead of dehydroxylated silica strongly enhanced the long-term stability under continuous flow operation. Virtually a single enantiopure product was obtained over a prolonged time-on-stream of 90 h (quantitative single-pass conversion, ee > 99%) reaching a total turnover number of 10 300 at a space-time yield (STY) of 24 g L-1 h-1. No metal contamination was detected in the product solutions, indicating effective catalyst retention.
- Geier, Daniel,Schmitz, Pascal,Walkowiak, J?drzej,Leitner, Walter,Franciò, Giancarlo
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- Preparation, characterization and catalytic activity of palladium catalyst supported on MgCO3 for dynamic kinetic resolution of amines
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Pd nanoparticle catalyst loading 4.7 wt.percent was prepared by the deposition-precipitation method and characterized by X-ray diffraction and transmission electron microscopy (TEM). The crystallite size estimated from the integral width of the highest intensity line using the Scherrer equation was 2.3 nm. Images obtained from TEM showed an equal distribution of the particles size between 0-2 and 2-4 nm, and also a good dispersion of the nanoparticles on the catalyst support. The catalytic activity of this nanocatalyst was studied for racemization reactions of (S)-(-)-1-phenylethylamine. After that, the catalyst was used in the chemoenzymatic dynamic kinetic resolution (DKR) of some primary amines. Expressive yields and optical purities were obtained.
- Ferreira, Marina M. M.,Cabreira, Camila R.,Chaves, Pedro H. K.,Labussiére, Gabriela M.,Zimpeck, Renata C.,De Lima, Sania M.,De Siqueira, Fernanda A.
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- Experimental data and modelling of the interactions in solid state and in solution between (R) and (S) N-acetyl-α-methylbenzylamine. Influence on resolution by preferential crystallization
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The binary phase diagram between (R) and (S) N-acetyl-α-methylbenzylamine has been established by using differential scanning calorimetry and X-ray diffraction. Up to 337 K, the two enantiomers form an eutectic mixture without partial solid solution (i.e.
- Druot,Petit,Petit,Coquerel,Chanh
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Read Online
- Decarboxylative Ritter-Type Amination by Cooperative Iodine (I/III)─Boron Lewis Acid Catalysis
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Recent years have witnessed important progress in synthetic strategies exploiting the reactivity of carbocations via photochemical or electrochemical methods. Yet, most of the developed methods are limited in their scope to certain stabilized positions in molecules. Herein, we report a metal-free system based on the iodine (I/III) catalytic manifold, which gives access to carbenium ion intermediates also on electronically disfavored benzylic positions. The unusually high reactivity of the system stems from a complexation of iodine (III) intermediates with BF3. The synthetic utility of our decarboxylative Ritter-type amination protocol has been demonstrated by the functionalization of benzylic as well as aliphatic carboxylic acids, including late-stage modification of different pharmaceutical molecules. Notably, the amination of ketoprofen was performed on a gram scale. Detailed mechanistic investigations by kinetic analysis and control experiments suggest two mechanistic pathways.
- Narobe, Rok,Murugesan, Kathiravan,Schmid, Simon,K?nig, Burkhard
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p. 809 - 817
(2022/01/15)
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- Decarboxylative cross-nucleophile coupling via ligand-to-metal charge transfer photoexcitation of Cu(ii) carboxylates
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Reactions that enable carbon–nitrogen, carbon–oxygen and carbon–carbon bond formation lie at the heart of synthetic chemistry. However, substrate prefunctionalization is often needed to effect such transformations without forcing reaction conditions. The development of direct coupling methods for abundant feedstock chemicals is therefore highly desirable for the rapid construction of complex molecular scaffolds. Here we report a copper-mediated, net-oxidative decarboxylative coupling of carboxylic acids with diverse nucleophiles under visible-light irradiation. Preliminary mechanistic studies suggest that the relevant chromophore in this reaction is a Cu(ii) carboxylate species assembled in situ. We propose that visible-light excitation to a ligand-to-metal charge transfer (LMCT) state results in a radical decarboxylation process that initiates the oxidative cross-coupling. The reaction is applicable to a wide variety of coupling partners, including complex drug molecules, suggesting that this strategy for cross-nucleophile coupling would facilitate rapid compound library synthesis for the discovery of new pharmaceutical agents. [Figure not available: see fulltext.].
- Li, Qi Yukki,Gockel, Samuel N.,Lutovsky, Grace A.,DeGlopper, Kimberly S.,Baldwin, Neil J.,Bundesmann, Mark W.,Tucker, Joseph W.,Bagley, Scott W.,Yoon, Tehshik P.
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- Biocatalytic, Intermolecular C?H Bond Functionalization for the Synthesis of Enantioenriched Amides
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Directed evolution of heme proteins has opened access to new-to-nature enzymatic activity that can be harnessed to tackle synthetic challenges. Among these, reactions resulting from active site iron-nitrenoid intermediates present a powerful strategy to forge C?N bonds with high site- and stereoselectivity. Here we report a biocatalytic, intermolecular benzylic C?H amidation reaction operating at mild and scalable conditions. With hydroxamate esters as nitrene precursors, feedstock aromatic compounds can be converted to chiral amides with excellent enantioselectivity (up to >99 % ee) and high yields (up to 87 %). Kinetic and computational analysis of the enzymatic reaction reveals rate-determining nitrenoid formation followed by stepwise hydrogen atom transfer-mediated C?H functionalization.
- Arnold, Frances H.,Athavale, Soumitra V.,Gao, Shilong,Hirschi, Jennifer S.,Liu, Zhen,Mallojjala, Sharath Chandra
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supporting information
p. 24864 - 24869
(2021/10/15)
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- Electrocatalytic ethylbenzene valorization using a polyoxometalate@covalent triazine framework with water as the oxygen source
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Ethylbenzene (EB) oxidation is an important transformation in the chemical industry. Herein, PMo10V2@CTF, a noble metal free electrocatalyst, was used to promote the oxidative upgrading of EB. Under ambient conditions, 65% of EB was converted to three value-added products using water as the oxygen source yielding a total Faraday efficiency of 90.4%. This excellent performance is ascribed to the homogeneous dispersion of PMo10V2and its dual role in the electrocatalytic process.
- Chi, Yingnan,Dong, Jing,Geng, Weijie,Hu, Changwen,Li, Zhen,Liu, Chengpeng
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supporting information
p. 7430 - 7433
(2021/08/03)
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- Chiral phosphine-phosphoramidite ester ligand as well as preparation method and application thereof
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The invention provides a method for preparing a phosphine-phosphoramidite ester ligand from a chiral beta-aminophosphine intermediate and an application of the phosphine-phosphoramidite ester ligand in an asymmetric reaction. Chiral N-(2-(phosphoryl)-1-phenethyl) amide is prepared from the chiral beta-aminophosphine intermediate through an asymmetric hydrogenation reaction of (Z)-(alpha-aryl-beta-phosphoryl) alkenyl amide, and then hydrolysis reduction. The preparation method comprises the following steps: dissolving newly-prepared chlorinated phosphite in toluene, adding a solution formed by dissolving the chiral phosphine-amine compound and triethylamine in toluene into an ice-water bath according to a molar ratio of the chiral phosphine-amine compound to the chlorinated phosphite to the triethylamine of 1: (1-2): (3-5), heating the reaction solution to 18-25 DEG C, stirring and reacting for 10-30 hours, filtering, and carrying out column chromatography to remove the solvent, and recrystallizing to obtain the required phosphine-phosphoramidite ligand. According to the present invention, the asymmetric hydrogenation reaction of the catalyst formed by the ligand and the metal precursor on the double bonds such as C = C, C = N, C = O and the like can achieve the enantioselectivity of 99%; the catalyst is high in activity, and TON reaches up to 10000.
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Paragraph 0054-0057; 0081-0084; 0093-0094
(2021/05/22)
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- Tropylium-promoted Ritter reactions
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The Ritter reaction used to be one of the most powerful synthetic tools to functionalize alcohols and nitriles, providing valuableN-alkyl amide products. However, this reaction has not been frequently used in modern organic synthesis due to its employment of strongly acidic and harsh reaction conditions, which often lead to complicated side reactions. Herein, we report the development of a new method using salts of the tropylium ion to promote the Ritter reaction. This method works well on a range of alcohol and nitrile substrates, giving the corresponding products in good to excellent yields. This reaction protocol is amenable to microwave and continuous flow reactors, offering an attractive opportunity for further applications in organic synthesis.
- Doan, Son H.,Hussein, Mohanad A.,Nguyen, Thanh Vinh
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supporting information
p. 8901 - 8904
(2021/09/10)
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- Preparation and catalytic evaluation of a palladium catalyst deposited over modified clinoptilolite (Pd&at;MCP) for chemoselective N-formylation and N-acylation of amines
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Novel palladium nanoparticles stabilized by clinoptilolite as a natural inexpensive zeolite prepared and used for N-formylation and N-acylation of amines at room temperature at environmentally benign reaction conditions in good to excellent yields. Pd (II) was immobilized on the surface of clinoptilolite via facile multi-step amine functionalization to obtain a sustainable, recoverable, and highly active nano-catalyst. The structural and morphological characterizations of the catalyst carried out using XRD, FT-IR, BET and TEM techniques. Moreover, the catalyst is easily recovered using simple filtration and reused for 7 consecutive runs without any loss in activity.
- Amirsoleimani, Mina,Khalilzadeh, Mohammad A.,Zareyee, Daryoush
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- Synthesis of acetamides via oxidative C–C bond cleavage of ketones catalyzed by Cu-immobilized magnetic nanoparticles
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Copper supported on magnetite nanoparticles modified with environmentally friendly ligand tricine was devised for synthesis of acetamides via C–C oxidative cleavage of ketones with amines. The catalyst was characterized using different techniques, including Fourier transform infrared, X-ray diffraction, scannin electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, and energy dispersive x-ray spectroscopy. The protocol showed relatively high yields of acetamide products. Furthermore, the magnetic recovery of the catalyst rendered the overall process fast and efficient. It was used in the reaction for six consecutive cycles with negligible loss of catalytic activity. This research is the first report of application of magnetic nanocatalysts for synthesis of acetamides from ketones of low activity through a C–C bond cleavage strategy.
- Yazdani, Elahe,Pazoki, Farzane,Salamatmanesh, Arefe,Nejad, Masoume Jadidi,Miraki, Maryam Kazemi,Heydari, Akbar
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- Reductive Amidation without an External Hydrogen Source Using Rhodium on Carbon Matrix as a Catalyst
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An efficient method for preparation of secondary amides from primary amides and aldehydes using rhodium on carbon matrix as catalyst was developed. The method does not require any external hydrogen source and carbon monoxide is used as a reducing agent. The most active rhodium catalysts were characterized by BET, TEM and XPS techniques. Unexpectedly, it was found that heterogeneous rhodium on carbon matrix works as precatalyst for homogenous active species due to leaching of rhodium to the solution. Various secondary amides were synthesized and checked for antifungal activity. 4-Methoxy-N-(4-methoxybenzyl)benzamide demonstrated promising activity against Rhizoctonia Solani.
- Tsygankov, Alexey A.,Makarova, Maria,Afanasyev, Oleg I.,Kashin, Alexey S.,Naumkin, Alexander V.,Loginov, Dmitry A.,Chusov, Denis
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p. 112 - 117
(2019/11/28)
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- Copper-catalyzed oxidative benzylic C(sp3)-H amination: Direct synthesis of benzylic carbamates
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A new efficient strategy to access benzylic carbamates through C-H activation is reported. The use of a catalytic amount of a Cu(i)/diimine ligand in combination with NFSI ((PhSO2)2NF) or F-TEDA-PF6 as oxidants and H2NCO2R as an amine source directly leads to the C-N bond formation at the benzylic position. The mild reaction conditions and the broad substrate scope make this transformation a useful method for the late-stage incorporation of a ubiquitous carbamate fragment onto hydrocarbons. This journal is
- Liu, Shuai,Achou, Rapha?l,Boulanger, Coline,Pawar, Govind,Kumar, Nivesh,Lusseau, Jonathan,Robert, Frédéric,Landais, Yannick
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supporting information
p. 13013 - 13016
(2020/11/05)
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- Chemoselective formation of C–N bond in wet acetonitrile using amberlyst-15(H) as a recyclable catalyst
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An economically efficient and environmentally benign protocol for the chemoselective one-pot synthesis of diversely N-substituted amides has been developed in good yield through the reaction of benzylic secondary alcohols as well as aliphatic tertiary alcohols and alkyl/aryl nitriles. Commercially available Amberlyst-15(H) has been utilized at 80 °C as an air-stable and reusable heterogeneous inexpensive solid acid catalyst without any anhydrous and inert environment. The attractive features of the present synthetic protocol are mild reaction conditions, short reaction time, excellent chemoselectivity, high atom economy and tolerance of various sensitive moieties.
- Nandy, Sneha,Das, Asit Kumar,Bhar, Sanjay
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p. 3326 - 3336
(2020/08/13)
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- A magnetically recoverable copper–salen complex as a nano-catalytic system for amine protection via acetylation using thioacetic acid
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A novel copper(II)–salen complex was immobilized on the surface of magnetite nanoparticles using chitosan as a linker. This system exhibits superior catalytic activity in acetyl protection of various amines with thioacetic acid as the acetylating reagent. The method has advantages over others in high selectivity, simple work-up, green reaction medium and the application of an easily recoverable heterogeneous catalyst.
- Yazdani, Elahe,Kazemi Miraki, Maryam,Salamatmanesh, Arefe,Azarnia, Jamshid,Azizi, Kobra,Ghandi, Leila,Heydari, Akbar
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p. 1775 - 1793
(2019/01/16)
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- Citric acid stabilized on the surface of magnetic nanoparticles as an efficient and recyclable catalyst for transamidation of carboxamides, phthalimide, urea and thiourea with amines under neat conditions
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Abstract: Citric acid-coated magnetic nanoparticles (Fe3O4–CA NPs) were successfully prepared and characterized. This magnetic nanocatalyst was employed as an efficient, recyclable, and environmentally benign heterogeneous catalyst for the transamidation of carboxamides, phthalimide, urea and thiourea with amines. Several derivatives of formylated and transamidated products were synthesized in good to excellent yields in the presence of this catalytic system. And, the catalyst could be easily separated from the reaction mixture using an external magnet and can be reused six times without any significant loss in its catalytic activity. Graphical abstract: [Figure not available: see fulltext.].
- Arefi, Marzban,Kazemi Miraki, Maryam,Mostafalu, Ramin,Satari, Mohammad,Heydari, Akbar
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p. 393 - 400
(2019/01/28)
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- Environmentally Benign Ritter Reaction Using Bismuth Salts as a Catalyst
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We developed an environmentally benign Ritter reaction of alcohols with nitriles using a commercially available bismuth salt as a less harmful catalyst. The detailed reaction profiles revealed that consumption of the ether by-product as the reaction proceeded was the key for optimizing this reaction, and the yield of the target amide was improved by adding a small amount of water. This finding clearly reveals the significance of using a bismuth salt as the catalyst, as it is not deactivated in the presence of water. This catalyst system has a broad substrate scope, and even with 1 mol-% of the catalyst, the reaction progresses smoothly. It is also possible to react stoichiometric amounts of nitriles and alcohols, thus reducing the amount of organic solvent required for the reaction. Furthermore, as the inexpensive bismuth catalyst can be easily removed using aqueous hydrochloric acid, a purification process that only required washing and drying without any organic solvents was successfully established.
- Ueno, Masaharu,Kusaka, Ryo,Ohmura, Satoshi D.,Miyoshi, Norikazu
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supporting information
p. 1796 - 1800
(2019/02/07)
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- Bifunctional Pincer Catalysts for Chemoselective Transfer Hydrogenation and Related Reactions
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A comparative study on the chemoselective transfer hydrogenation of nitroarenes to anilines and related processes using FA as the hydrogen source is described; these processes are catalyzed by a series of pincer catalysts equipped with different functional groups in the secondary coordination sphere. Some new (4 and 5) as well as previously reported (1–3) catalysts belonging to the family of bifunctional PC(sp3)P pincer complexes were employed in this study The reported compounds exhibited remarkably different catalytic activity behavior, depending on the nature of the functional groups. Transfer hydrogenation of nitrobenzene with FA as a hydrogen source was probed using iridium complexes 3 or 4 as a catalyst. Under the same conditions, the analogous palladium complex was found to be useful for the selective amidation of aniline with light carboxylic acids.
- Cohen, Shirel,Bilyachenko, Alexey N.,Gelman, Dmitri
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p. 3203 - 3209
(2019/02/09)
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- Quinazoline derivatives and its preparation method and application
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The invention relates to quinazoline derivatives and its preparation method and application. The quinazoline derivatives with The structural formula, the quinazoline derivative to gefitinib for the positive control, the result shows that compared with the gefitinib has good activity; and lead compound OTS514 compared, equivalent activity, PBK/TOPK inhibitors for further transformation and the discovery of new anti-tumor medicine phenological shopping has higher learning with the reference value. The invention also provides a preparation method of the quinazoline derivatives and the preparation of PBK/TOPK inhibitor and an anticancer drug.
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Paragraph 0148-0152
(2019/07/08)
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- Nickel-Catalyzed Highly Enantioselective Hydrogenation of β-Acetylamino Vinylsulfones: Access to Chiral β-Amido Sulfones
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The nickel/(S)-Binapine complex was found to be an efficient catalyst for asymmetric hydrogenation of β-acetylamino vinylsulfones to afford chiral β-Amido sulfones with excellent yields and enantioselectivities (up to 95% yields and >99% ee). This protocol has good compatibility with a series of substituted (Z)-β-acetylamino vinylsulfones or Z/E isomeric mixtures. A gram-scale reaction has also been achieved in the presence of a 0.2 mol % catalyst loading.
- Long, Jiao,Gao, Wenchao,Guan, Yuqing,Lv, Hui,Zhang, Xumu
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p. 5914 - 5917
(2018/09/25)
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- Systematic Evaluation of Sulfoxides as Catalysts in Nucleophilic Substitutions of Alcohols
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Herein, a method for the nucleophilic substitution (SN) of benzyl alcohols yielding chloro alkanes is introduced that relies on aromatic sulfoxides as Lewis base catalysts (down to 1.5 mol-%) and benzoyl chloride (BzCl) as reagent. A systematic screening of various sulfoxides and other sulfinyl containing Lewis bases afforded (2-methoxyphenyl)methyl sulfoxide as optimal catalyst. In contrast to reported formamide catalysts, sulfoxides also enable the application of plain acetyl chloride (AcCl) as reagent. In addition, it was demonstrated that weakly electrophilic carboxylic acid chlorides like BzCl promote Pummerer rearrangement of sulfoxides already at room temperature. This side-reaction also provided the explanation, why sulfoxide catalyzed SN-reactions of alcohols do not allow the effective production of aliphatic and electron deficient chloro alkanes. Comparison experiments provided further insight into the reaction mechanism.
- Motsch, Sebastian,Schütz, Christian,Huy, Peter H.
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supporting information
p. 4541 - 4547
(2018/09/13)
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- Copper-(II) Catalyzed N-Formylation and N-Acylation of Aromatic, Aliphatic, and Heterocyclic Amines and a Preventive Study in the C-N Cross Coupling of Amines with Aryl Halides
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A Cu-(II) catalyzed N-formylation and N-acylation of amines with moderate to excellent yields, using N, N-dimethyl formamide (DMF) and N, N-dimethyl acetamide (DMA) as a formyl and acylating sources in the presence of 1,2,4-triazole is reported. This novel, highly efficient and simple protocol shows broad substrate scope for aliphatic, aromatic, and heterocyclic amines. In addition, the conditions to prevent N-formylation and N-acylation impurities in the C?N cross coupling of amines and aryl halides are described typically when DMF and DMA are used as solvents, with various catalysts, ligands, and bases.
- Sonawane, Rahul B.,Rasal, Nishant K.,Bhange, Dattatraya S.,Jagtap, Sangeeta V.
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p. 3907 - 3913
(2018/09/12)
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- Modular 1,1′-Ferrocenediyl-cored P-Stereogenic Diphosphines: ′′JDayPhos′′ Series and its Use in Rhodium(I)-Catalyzed Hydrogenation
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A novel ferrocene-based P-stereogenic diphospine ligand series dubbed JDayPhos was developed, which rhodium(I) complexes of some of its members exhibited excellent enantioselectivity (up to >99% ee) and high activity in asymmetric hydrogenation of β-unsubstituted or -substituted itaconates and α-methylene-γ-oxo-carboxylates. (Figure presented.).
- Poklukar, Ga?per,Stephan, Michel,Mohar, Barbara
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supporting information
p. 2566 - 2570
(2018/05/16)
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- Air-stable Bis(pentamethylcyclopentadienyl) Zirconium Perfluorooctanesulfonate as an Efficient and Recyclable Catalyst for the Synthesis of N-substituted Amides
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Bis(pentamethylcyclopentadienyl) zirconium perfluorooctanesulfonate is an air-stable and water-tolerant Lewis acid. This complex exhibited good thermal stability and high solubility in polar organic solvents. The compound showed relatively strong acidity, with an acid strength of 0.8Ho≤3.3, and high catalytic efficiency for the synthesis of N-substituted amides via the reaction of carboxylic acids with amines, the Ritter reaction of nitriles with alcohols, and the amination of alcohols with amides. Moreover, the complex had good reusability. This catalytic system affords a simple and efficient way to synthesize N-substituted amides.
- Li, Ningbo,Wang, Lingxiao,Zhang, Liting,Zhao, Wenjie,Qiao, Jie,Xu, Xinhua,Liang, Zhiwu
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p. 3532 - 3538
(2018/08/01)
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- Mild and eco-friendly chemoselective acylation of amines in aqueous medium using a green, superparamagnetic, recoverable nanocatalyst
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Copper-grafted guanidine acetic acid-modified magnetite nanoparticles (Fe3O4@GAA-Cu(II)) as a green, superparamagnetic and recoverable nanocatalyst is found to promote quantitative N-acylation of various amines in a very short time with an equimolar amount of thioacetic acid in water at room temperature. This method is found to be highly selective for amines and not sensitive to other functional groups. Mild reaction condition, high selectivity, efficiency, simple workup and excellent yields are some of the major advantages of the procedure.
- Miraki, Maryam Kazemi,Yazdani, Elahe,Ghandi, Leila,Azizi, Kobra,Heydari, Akbar
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- Directed β C-H Amination of Alcohols via Radical Relay Chaperones
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A radical-mediated strategy for β C-H amination of alcohols has been developed. This approach employs a radical relay chaperone, which serves as a traceless director that facilitates selective C-H functionalization via 1,5-hydrogen atom transfer (HAT) and enables net incorporation of ammonia at the β carbon of alcohols. The chaperones presented herein enable direct access to imidate radicals, allowing their first use for H atom abstraction. A streamlined protocol enables rapid conversion of alcohols to their β-amino analogs (via in situ conversion of alcohols to imidates, directed C-H amination, and hydrolysis to NH2). Mechanistic experiments indicate HAT is rate-limiting, whereas intramolecular amination is product- and stereo-determining.
- Wappes, Ethan A.,Nakafuku, Kohki M.,Nagib, David A.
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p. 10204 - 10207
(2017/08/10)
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- An Unconventional Reaction of 2,2-Diazido Acylacetates with Amines
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We have discovered that 2,2-diazido acylacetates, a class of compounds with essentially unknown reactivity, can be coupled to amines through a new strategy that does not involve any reagents. 2,2-Diazido acetate is the unconventional leaving group under carbon–carbon bond cleavage. This reaction leads to the construction of amide bonds, tolerates various functionalities and is performed equally well in numerous solvents under experimentally simple conditions. We also demonstrate that the isolation of the 2,2-diazido acylacetate compounds can be circumvented: Acylacetates were easily fragmented when treated with (Bu4N)N3 and iodine in the presence of an amine at room temperature. By using this method, a broad range of acylacetates with various structural motifs were directly transformed into amides.
- H?ring, Andreas P.,Biallas, Phillip,Kirsch, Stefan F.
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supporting information
p. 1526 - 1539
(2017/04/01)
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- Cleavage of 1,3-dicarbonyls through oxidative amidation
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A mild and convenient protocol for the oxidative cleavage of 1,3-diketone compounds is described. Under metal-free conditions, the method converts the 1,3-dicarbonyls into amides when treated with (nBu4N)N3 and iodine in the presence of an amine at room temperature. Using this method, a range of 1,3-dicarbonyls with various structural motifs including sterically demanding substituents and ordinary functional groups were easily fragmented, and it is demonstrated that cyclic 1,3-dicarbonyls can be directly transformed into acyclic diamides through ring-opening. Initial mechanistic studies show that diazidation of the enol form is followed by nucleophilic substitution with the amine.
- Biallas, Phillip,H?ring, Andreas P.,Kirsch, Stefan F.
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supporting information
p. 3184 - 3187
(2017/04/21)
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- An unexpected copper-catalyzed carbonylative acetylation of amines
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A novel copper-catalyzed carbonylative acetylation of amines has been developed. With peroxide as the oxidant as well as the methyl source with a copper catalyst under CO pressure, good yields of N-acetyl amides could be obtained. Notably, this is the first example of carbonylative acetylation.
- Li, Yahui,Wang, Changsheng,Zhu, Fengxiang,Wang, Zechao,Fran?ois Soulé, Jean,Dixneuf, Pierre H.,Wu, Xiao-Feng
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supporting information
p. 142 - 144
(2016/12/27)
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- Manganese(III) acetate catalyzed oxidative amination of benzylic C(sp3)-H bonds with nitriles
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Mn-Catalyzed oxidative amination of benzylic C(sp3)-H bonds with nitriles is disclosed, which enables the synthesis of a broad range of secondary amides in moderate to excellent yields under mild conditions. The interaction between Mn(iii) and DDQ facilitates the oxidation and makes it highly efficient and selective.
- Zhang, Yaxing,Dong, Jianyu,Liu, Lixin,Liu, Long,Zhou, Yongbo,Yin, Shuang-Feng
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supporting information
p. 2897 - 2901
(2017/04/11)
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- Method for preparing amide from aryl methane derivative and nitrile
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The invention provides a simple and efficient method for directly preparing an amide compound from an aryl methane derivative and nitrile. In the method, manganese triacetate dihydrate is used as a catalyst, and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone(DDQ) is used as an oxidizing agent. The method has the characteristics that raw materials are cheap and easy to obtain, the source of the nitrile is wide, reaction conditions are mild, the applicability is wide and the like. The method solves the problems that ceric ammonium nitrate (CAN) and a fluorine agent which are used by a method for directly synthesizing amide by using aryl methane and nitrile compounds are hard to treat, atomic economy is poor, the source of the nitrile is narrow and the like.
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Paragraph 0026-0028
(2017/05/10)
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- Tuneable 3D printed bioreactors for transaminations under continuous-flow
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A method to efficiently immobilize enzymes on 3D printed continuous-flow devices is presented. Application of these chemically modified devices enables rapid screening of immobilization mechanisms and reaction conditions, simple transfer of optimised conditions into tailored printed microfluidic reactors and development of continuous-flow biocatalytic processes. The bioreactors showed good activity (8-20.5 μmol h-1 mgenz-1) in the kinetic resolution of 1-methylbenzylamine, and very good stability (ca. 100 h under flow).
- Peris, Edgar,Okafor, Obinna,Kulcinskaja, Evelina,Goodridge, Ruth,Luis, Santiago V.,Garcia-Verdugo, Eduardo,O'Reilly, Elaine,Sans, Victor
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supporting information
p. 5345 - 5349
(2017/11/22)
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- Transition metal complex, chiral alpha-amino tertiary borate and preparing methods thereof
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The invention discloses a transition metal complex, chiral alpha-amino tertiary borate and preparing methods thereof. The chiral alpha-amino tertiary borate preparing method comprises the step of mixing a compound II, a metal ligand complex and bis(pinaco
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- Potassium Thioacids Mediated Selective Amide and Peptide Constructions Enabled by Visible Light Photoredox Catalysis
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A remarkable visible-light-promoted photoredox catalytic methodology involved with amines and eco-friendly potassium thioacids for amide formation was uncovered. This approach can mimic the natural coenzyme acetyl-CoA to selectively acylate amines without affecting other functional groups such as alcohols, phenols, esters, among others. The developed strategy may hold great potential for a comprehensive display of biologically interesting peptide synthesis and amino acid modification through a diacyl disulfide intermediate.
- Liu, Hongxin,Zhao, Liyun,Yuan, Yunfei,Xu, Zhifang,Chen, Kai,Qiu, Shengxiang,Tan, Haibo
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p. 1732 - 1736
(2016/03/15)
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- Transamidation of primary carboxamides, phthalimide, urea and thiourea with amines using Fe(OH)3@Fe3O4 magnetic nanoparticles as an efficient recyclable catalyst
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The highly efficient transamidation of primary amides, phthalimide, urea and thiourea with amines catalyzed by magnetic Fe(OH)3@Fe3O4 nanoparticles is described. This magnetic nanocomposite is able to catalyze transamidation reactions of a wide range of the above-mentioned substrates with amines, generating a new amide bond in moderate to good yields. The catalyst exhibited very good recyclability and reusability up to five runs without significant loss of its catalytic activity.
- Arefi, Marzban,Heydari, Akbar
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p. 24684 - 24689
(2016/03/16)
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- Direct Preparation of Amides from Amine Hydrochloride Salts and Orthoesters: A Synthetic and Mechanistic Perspective
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The conversion of a wide range of primary and secondary aliphatic and a few arylamine hydrochloride salts to their corresponding acetamides with trimethyl orthoacetate is described. Mechanistic studies using NMR and gas chromatography-mass spectrometry techniques indicate these reactions proceed via an O-methylimidate intermediate that undergoes in situ demethylation by chloride, affording the corresponding acetamides. Synthetically, this reaction represents a practical, high-yielding protocol with a simple workup for the rapid conversion of amine hydrochloride salts to acetamides.
- Di Grandi, Martin J.,Bennett, Caitlin,Cagino, Kristen,Muccini, Arnold,Suraci, Corey,Saba, Shahrokh
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p. 2601 - 2607
(2015/11/28)
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- Direct photocatalytic fluorination of benzylic C-H bonds with N-fluorobenzenesulfonimide
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The late-stage fluorination of common synthetic building blocks and drug leads is an appealing reaction for medicinal chemistry. In particular, fluorination of benzylic C-H bonds provides a means to attenuate drug metabolism at this metabolically labile position. Here we report two complimentary strategies for the direct fluorination of benzylic C-H bonds using N-fluorobenzenesulfonimide and either a decatungstate photocatalyst or AIBN-initiation.
- Nodwell, Matthew B.,Bagai, Abhimanyu,Halperin, Shira D.,Martin, Rainer E.,Knust, Henner,Britton, Robert
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supporting information
p. 11783 - 11786
(2015/07/15)
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- Synthesis of chiral α-amino tertiary boronic esters by enantioselective hydroboration of α-arylenamides
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The rhodium-catalyzed asymmetric hydroboration of α-arylenamides with BI-DIME as the chiral ligand and (Bpin)2 as the reagent yields for the first time a series of α-amino tertiary boronic esters in good yields and excellent enantioselectivities (up to 99% ee).
- Hu, Naifu,Zhao, Guoqing,Zhang, Yuanyuan,Liu, Xiangqian,Li, Guangyu,Tang, Wenjun
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supporting information
p. 6746 - 6749
(2015/06/16)
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- Convenient N-acetylation of amines in N,N-dimethylacetamide with N,N-carbonyldiimidazole
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Dimethylacetamide (DMAc) acts as an efficient source of acetyl and dimethylamine gas in the presence of N,N-carbonyldiimidazole (CDI). Addition of amines to the reaction mixture delivers the corresponding amides in good to excellent yields. The acetylation of amines reported herein, which relies on the in situ generation of N-acetylimidazole on warming of DMAc with CDI at 120-125 °C, serves as a convenient alternative to other acetylation methods.
- Chikkulapalli, Anil,Aavula, Sanjeev Kumar,Mona Np, Rifahath,Karthikeyan, Karthikeyan,Kumar C.H., Vinodh,Sulur G., Manjunatha,Sumathi, Shanmugam
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supporting information
p. 3799 - 3803
(2015/06/08)
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- H-β-zeolite catalyzed transamidation of carboxamides, phthalimide, formamides and thioamides with amines under neat conditions
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Efficient transamidation of unactivated carboxamides, phthalimides, formamides and thioamides with amines under solvent-free conditions using H-β-zeolite as a green and recyclable heterogeneous catalyst is described. Easy work up, high purity of the products, recyclability and environmentally-friendly nature of the catalyst are the attractive features of the present methodology. This is the first report for the transamidation of thioamides under heterogeneous conditions.
- Rao, Sadu Nageswara,Chandra Mohan, Darapaneni,Adimurthy, Subbarayappa
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p. 95313 - 95317
(2015/11/24)
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- Designing of thermally stable amide functionalized benzimidazolium perchlorate ionic liquid for transamidation of primary carboxamides
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In the present work, we have designed and synthesized a thermally stable catalyst based on functionalized benzimidazolium perchlorate ionic liquid and tested its efficacy towards metal free and solvent free transamidation of amides and amines. The ionic liquid comprising the perchlorate ion has shown remarkably better activity than those which contain other anions and accordingly a plausible mechanism for the catalytic activity is arrived. The developed catalytic system has shown excellent activity towards the transamidation of alicyclic and aromatic amines with acetamide, benzamide and p-nitrobenzamide under mild conditions. Furthermore, the transamidation of nicotinamide with benzylamine in presence of the ionic liquid catalyst was found to occur with very good yields and thus provides a facile route for the synthesis of pharmaceutically significant compounds. The catalyst has exhibited very good thermal stability upto 203 °C and very good recyclability upto 5 runs without significant loss in its activity.
- Muskawar, Prashant Narayan,Thenmozhi,Bhagat, Pundlik Rambhau
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p. 158 - 167
(2015/09/28)
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- A Single Lipase-Catalysed One-Pot Protocol Combining Aminolysis Resolution and Aza-Michael Addition: An Easy and Efficient Way to Synthesise β-Amino Acid Esters
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A novel one-pot protocol combining aza-Michael addition and aminolysis resolution was developed to obtain chiral β-amino acid esters with lipase B from Candida antarctica (CAL-B) as the only catalyst. This method is conducted under mild reaction conditions and is very easy to handle. After a series of detailed optimization studies, ten racemic aromatic or aliphatic amines were subjected to this one-pot procedure, and twelve chiral β-amino acid esters and ten chiral amides were successfully synthesised with excellent ee values in theoretical yields. Scaled-up procedures also worked without apparent reduction in reaction rate or enantioselectivity, which makes this method suitable for large-scale production of chiral β-amino acid esters. A one-pot protocol for simultaneous synthesis of chiral β-amino acid esters and amides was developed by combining single lipase B from Candida antarctica (CAL-B) catalysed aza-Michael addition and aminolysis resolution. This method requires mild reaction conditions and is very easy to handle. Chiral β-amino acid esters and chiral amides were obtained with excellent ee values and in theoretical yields.
- Xu, Fan,Wu, Qiongsi,Chen, Xiaoyang,Lin, Xianfu,Wu, Qi
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p. 5393 - 5401
(2015/08/24)
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- Palladium nanocarbon catalysts (Pd/CNT) as potential enantioselective heterogeneous systems. the behavior in the hydrogenation and hydroarylation of unsaturated substrates
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Hydroxy-CNT were modified with optically active α-amino acids. The resulting chiral derivatives were directly palladated with Pd2dba3 and used to catalyze the hydrogenation of α-acetamidostyrene and α-phenylcinnamic acid as well as t
- Abramova,Turova,Davidovich, Yu. A.,Sokolov
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p. 216 - 218
(2015/10/05)
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- Iron-catalyzed olefin hydrogenation at 1 bar H2 with a FeCl3-LiAlH4 catalyst
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The scope and mechanism of a practical protocol for the iron-catalyzed hydrogenation of alkenes and alkynes at 1 bar H2 pressure were studied. The catalyst is formed from cheap chemicals (5 mol% FeCl3-LiAlH4, THF). A homogeneous mechanism operates at early stages of the reaction while active nanoparticles form upon ageing of the catalyst solution. This journal is
- Gieshoff, Tim N.,Villa, Matteo,Welther, Alice,Plois, Markus,Chakraborty, Uttam,Wolf, Robert,Jacobi Von Wangelin, Axel
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supporting information
p. 1408 - 1413
(2015/03/18)
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- Mechanochemical ritter reaction: A rapid approach to functionalized amides at room temperature
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A fast and efficient mechanochemical Ritter reaction between alcohols and nitriles under mild conditions is demonstrated. The reaction proceeds rapidly at room temperature in a solvent-free or low-solvent environment by using a Br?nsted acid catalyst. Its general application has been verified through a substrate screening comprising a wide range of functionalized nitriles as well as secondary and tertiary alcohols. Gentle Ritter: A fast and efficient mechanochemical Ritter reaction under mild conditions is described. The reaction proceeds rapidly at room temperature in a solvent-free or low-solvent environment by using sulfuric acid as catalyst.
- Dokli, Irena,Gredi?ak, Matija
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supporting information
p. 2727 - 2732
(2015/04/27)
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- An eco-friendly and highly efficient route for N-acylation under catalyst-free conditions
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An eco-friendly, simple, mild, chemoselective and highly efficient procedure for the acylation of primary and secondary amine function in various structurally and electronically aliphatic and aromatic compounds affording their corresponding N-Ac derivatives is developed. Mild conditions, simplicity and easier work-up are the main advantages of this method.
- Ouarna, Souad,K'tir, Hacène,Lakrout, Salah,Ghorab, Hamida,Amira, A?cha,Aouf, Zineb,Berredjem, Malika,Aouf, Nour-Eddine
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p. 913 - 919
(2015/10/28)
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- Silver-catalyzed radical fluorination of alkylboronates in aqueous solution
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We report herein an efficient and general method for the deboronofluorination of alkylboronates. Thus, with the catalysis of AgNO3, the reactions of various alkylboronic acids or their pinacol esters with Selectfluor reagent in acidic aqueous solution afforded the corresponding alkyl fluorides under mild conditions. A broad substrate scope and wide functional group compatibility were observed. A radical mechanism is proposed for this site-specific fluorination.
- Li, Zhaodong,Wang, Zhentao,Zhu, Lin,Tan, Xinqiang,Li, Chaozhong
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supporting information
p. 16439 - 16443
(2015/01/09)
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- Green synthesis of benzamides in solvent- and activation-free conditions
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Herein, we describe a clean and ecocompatible pathway for both N-benzoylation and N-acetylation of anilines, amines, diamines, and aminoalcohols using three enol esters with good yields. We have improved the use of vinyl benzoate for the direct introduction of a benzamido-moiety under solvent- and activation-free conditions. The recovered amides are easily isolated by crystallization. Copyright
- Alalla, Affef,Merabet-Khelassi, Mounia,Aribi-Zouioueche, Louisa,Riant, Olivier
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supporting information
p. 2364 - 2376
(2014/07/22)
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- Metallacrown ether catalysts containing phosphine-phosphite polyether ligands for Rh-catalyzed asymmetric hydrogenation - Enhancements in activity and enantioselectivity
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A new class of tunable metallacrown ether rhodium catalysts based on α,ω-(phosphine-phosphite) polyether ligands were prepared either by a template-induced method or by a nontemplate procedure. For the asymmetric hydrogenation of α-arylenamides with the a
- Song, Feng-Tao,Ouyang, Guang-Hui,Li, Yong,He, Yan-Mei,Fan, Qing-Hua
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supporting information
p. 6713 - 6719
(2016/02/18)
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- Microwave assisted, Ca(II)-catalyzed Ritter reaction for the green synthesis of amides
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An efficient solvent-free synthesis of amides by Ca(II) catalyzed Ritter reaction has been reported under microwave irradiation. This green protocol tolerates the substrate diversity and delivers the high yielding amides with minimal loading of inexpensive and more abundant Ca(II) catalyst.
- Yaragorla, Srinivasarao,Singh, Garima,Lal Saini, Pyare,Reddy, M. Kesava
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p. 4657 - 4660
(2014/12/10)
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- Alcohols as electrophiles: Iron-catalyzed Ritter reaction and alcohol addition to alkynes
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A simple, iron-based catalytic system allows for a straightforward method for the synthesis of primary, secondary, and tertiary amides. The system also allows the addition of benzyl alcohols across phenylacetylene to produce substituted phenyl ketones. This transformation improves and expands the substrate scope beyond that previously reported and proceeds under mild reaction conditions, tolerating air and moisture.
- Jefferies, Latisha R.,Cook, Silas P.
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supporting information
p. 4204 - 4207
(2014/06/09)
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