- Photocatalysis in Aqueous Micellar Media Enables Divergent C-H Arylation and N-Dealkylation of Benzamides
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Photocatalysis in aqueous micellar media has recently opened wide avenues to activate strong carbon-halide bonds. So far, however, it has mainly explored strongly reducing conditions, restricting the available chemical space to radical or anionic reactivity. Here, we demonstrate a controllable, photocatalytic strategy that channels the reaction of chlorinated benzamides via either a radical or a cationic pathway, enabling a chemodivergent C-H arylation or N-dealkylation. The catalytic system operates under mild conditions with methylene blue as a photocatalyst and blue LEDs as the light source. Factors determining the reactivity of substrates, their selectivity, and preliminary mechanistic studies are presented.
- Cybularczyk-Cecotka, Martyna,Predygier, J?drzej,Crespi, Stefano,Szczepanik, Joanna,Giedyk, MacIej
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p. 3543 - 3549
(2022/03/27)
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- Cobalt-Catalyzed Deoxygenative Hydroboration of Nitro Compounds and Applications to One-Pot Synthesis of Aldimines and Amides
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The commercially available and bench-stable Co(acac)2 ligated with bis[(2-diphenylphosphino)phenyl] ether (dpephos) was employed for selective room temperature hydroboration of nitro compounds with HBPin (TOF up to 4615 h?1), tolerating halide, hydroxy, amino, ether, ester, lactone, amide and heteroaromatic functionalities. These reactions offered a direct access to a variety of N-borylamines RN(H)BPin, which were in situ treated with aldehydes and carboxylic acids to produce a series of aldimines and secondary carboxamides without the need for dehydrating and/or coupling reagents. Combination of these transformations in a sequential one-pot manner allowed for direct and selective synthesis of aldimines and secondary carboxamides from readily available and inexpensive nitro compounds.
- Gudun, Kristina A.,Zakarina, Raikhan,Segizbayev, Medet,Hayrapetyan, Davit,Slamova, Ainur,Khalimon, Andrey Y.
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p. 601 - 611
(2021/11/30)
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- COMPOUND HAVING KDM5 INHIBITORY ACTIVITY AND PHARMACEUTICAL USE THEREOF
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The present invention provides KDM5 inhibitor. The compound disclosed herein represented by the general formula (Z): wherein all symbols have the same meanings as the definitions described in the specification; or a salt thereof is useful as a prophylactic and/or therapeutic agent for cancer, Huntington's disease, or Alzheimer's disease and the like.
- -
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Page/Page column 105
(2021/02/12)
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- Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
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Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
- Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
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supporting information
p. 5022 - 5037
(2021/05/04)
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- Hydrogenation of Secondary Amides using Phosphane Oxide and Frustrated Lewis Pair Catalysis
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The metal-free catalytic hydrogenation of secondary carboxylic acid amides is developed. The reduction is realized by two new catalytic reactions. First, the amide is converted into the imidoyl chloride by triphosgene (CO(OCCl3)2) using novel phosphorus(V) catalysts. Second, the in situ generated imidoyl chlorides are hydrogenated in high yields by an FLP-catalyst. Mechanistic and quantum mechanical calculations support an autoinduced catalytic cycle for the hydrogenation with chloride acting as unusual Lewis base for FLP-mediated H2-activation.
- K?ring, Laura,Sitte, Nikolai A.,Bursch, Markus,Grimme, Stefan,Paradies, Jan
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supporting information
p. 14179 - 14183
(2021/09/03)
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- Weak base-promoted selective rearrangement of oxaziridines to amidesviavisible-light photoredox catalysis
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The selective rearrangement of oxaziridines to amidesviaa single electron transfer (SET) pathway is unexplored. In this study, we present a weak base-promoted selective rearrangement of oxaziridines to amidesviavisible-light photoredox catalysis. The developed method shows excellent functional group tolerance with a broad substrate scope and good to excellent yields. Furthermore, control experiments and density functional theory (DFT) calculations are performed to gain insight into the reactivity and selectivity.
- Park, Jin,Park, Sehoon,Jang, Gwang Seok,Kim, Ran Hui,Jung, Jaehoon,Woo, Sang Kook
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p. 9995 - 9998
(2021/10/06)
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- Photocatalyzed Triplet Sensitization of Oximes Using Visible Light Provides a Route to Nonclassical Beckmann Rearrangement Products
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Oximes are valuable synthetic intermediates for the preparation of a variety of functional groups. To date, the stereoselective synthesis of oximes remains a major challenge, as most current synthetic methods either provide mixtures of E and Z isomers or furnish the thermodynamically preferred E isomer. Herein we report a mild and general method to achieve Z isomers of aryl oximes by photoisomerization of oximes via visible-light-mediated energy transfer (EnT) catalysis. Facile access to (Z)-oximes provides opportunities to achieve regio- and chemoselectivity complementary to those of widely used transformations employing oxime starting materials. We show an enhanced one-pot protocol for photocatalyzed oxime isomerization and subsequent Beckmann rearrangement that enables novel reactivity with alkyl groups migrating preferentially over aryl groups, reversing the regioselectivity of the traditional Beckmann reaction. Chemodivergent N- or O- cyclizations of alkenyl oximes are also demonstrated, leading to nitrones or cyclic oxime ethers, respectively.
- Zhang, Xiao,Rovis, Tomislav
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supporting information
p. 21211 - 21217
(2021/12/27)
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- Metal-Free Selective Modification of Secondary Amides: Application in Late-Stage Diversification of Peptides
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Here we solve a long-standing challenge of the site-selective modification of secondary amides and present a simple two-step, metal-free approach to selectively modify a particular secondary amide in molecules containing multiple primary and secondary amides. Density functional theory (DFT) provides insight into the activation of C-N bonds. This study encompasses distinct chemical advances for late-stage modification of peptides thus harnessing the amides for the incorporation of various functional groups into natural and synthetic molecules.
- Adebomi, Victor,Sriram, Mahesh,Streety, Xavier,Raj, Monika
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supporting information
p. 6189 - 6193
(2021/08/01)
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- Iron-Catalyzed α-C-H Cyanation of Simple and Complex Tertiary Amines
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This manuscript details the development of a general and mild protocol for the α-C-H cyanation of tertiary amines and its application in late-stage functionalization. Suitable substrates include tertiary aliphatic, benzylic, and aniline-type substrates and complex substrates. Functional groups tolerated under the reaction conditions include various heterocycles and ketones, amides, olefins, and alkynes. This broad substrate scope is remarkable, as comparable reaction protocols for α-C-H cyanation frequently occur via free radical mechanisms and are thus fundamentally limited in their functional group tolerance. In contrast, the presented catalyst system tolerates functional groups that typically react with free radicals, suggesting an alternative reaction pathway. All components of the described catalyst system are readily available, allowing implementation of the presented methodology without the need for lengthy catalyst synthesis.
- Yilmaz, Ozgur,Dengiz, Cagatay,Emmert, Marion H.
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supporting information
p. 2489 - 2498
(2021/02/06)
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- Direct Amidation of Esters by Ball Milling**
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The direct mechanochemical amidation of esters by ball milling is described. The operationally simple procedure requires an ester, an amine, and substoichiometric KOtBu and was used to prepare a large and diverse library of 78 amide structures with modest to excellent efficiency. Heteroaromatic and heterocyclic components are specifically shown to be amenable to this mechanochemical protocol. This direct synthesis platform has been applied to the synthesis of active pharmaceutical ingredients (APIs) and agrochemicals as well as the gram-scale synthesis of an active pharmaceutical, all in the absence of a reaction solvent.
- Barreteau, Fabien,Battilocchio, Claudio,Browne, Duncan L.,Godineau, Edouard,Leitch, Jamie A.,Nicholson, William I.,Payne, Riley,Priestley, Ian
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supporting information
p. 21868 - 21874
(2021/09/02)
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- UV-Light-Induced N-Acylation of Amines with α-Diketones
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Herein, we develop a mild method for N-acylation of primary and secondary amines with α-diketones induced by ultraviolet (UV) light. Forty-six examples with various functional groups are explored at room temperature with irradiation by three 26 W UV lamps (350-380 nm). The yield reaches 97%. The gram scale experiment product yield is 76%. Moreover, this system can be applied to the synthesis of several amino acid derivatives. Mechanistic studies show that benzoin is generated in situ from benzil under UV irradiation.
- Xu, Zhihui,Yang, Tianbao,Tang, Niu,Ou, Yifeng,Yin, Shuang-Feng,Kambe, Nobuaki,Qiu, Renhua
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supporting information
p. 5329 - 5333
(2021/07/21)
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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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- Sulfuryl Fluoride Mediated Synthesis of Amides and Amidines from Ketoximes via Beckmann Rearrangement
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A metal-free and redox-neutral method for Beckmann rearrangement employing inexpensive and readily available SO2F2 gas is described. The reported transformation proceeds at ambient temperature and is compatible with a wide range of sterically and electronically diverse aromatic, heteroaromatic, aliphatic and lignin-like oximes providing amides in good to excellent yields. The reaction proceeds through the formation of an imidoyl fluoride intermediate that can also be used for the synthesis of amidines.
- Gurjar, Jitendra,Fokin, Valery V.
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supporting information
p. 10402 - 10405
(2020/07/25)
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- Visible-light-induced Beckmann rearrangement by organic photoredox catalysis
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A facile and general strategy for efficient direct conversion of oximes to amides using an inexpensive organic photocatalyst and visible light is described. This radical Beckmann rearrangement can be performed under mild conditions. Various alkyl aryl ketoximes and diaryl ketoximes can be effectively converted into the corresponding amides in excellent yields.
- Tang, Li,Wang, Zhi-Lv,Wan, Hai-Lan,He, Yan-Hong,Guan, Zhi
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supporting information
p. 6182 - 6186
(2020/09/01)
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- An Electrochemical Beckmann Rearrangement: Traditional Reaction via Modern Radical Mechanism
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Abstract: Electrosynthesis as a potential means of introducing heteroatoms into the carbon framework is rarely studied. Herein, the electrochemical Beckmann rearrangement, i. e. the direct electrolysis of ketoximes to amides, is presented for the first time. Using a constant current as the driving force, the reaction can be easily carried out under neutral conditions at room temperature. Based on a series of mechanistic studies, a novel radical Beckmann rearrangement mechanism is proposed. This electrochemical Beckmann rearrangement does not follow the trans-migration rule of the classical Beckmann rearrangement.
- Tang, Li,Wang, Zhi-Lv,He, Yan-Hong,Guan, Zhi
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p. 4929 - 4936
(2020/08/21)
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- Synthesis of CF3-containing isoindolinone derivatives through rhodium-catalyzed oxidative coupling of benzamides with 2-trifluoromethylacrylate
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The oxidative coupling of benzamides with methyl 2- trifluoromethylacrylate proceeds smoothly under rhodium(III) catalysis to produce trifluoromethyl-substituted isoindolinone derivatives. The catalyst system [CpERhCl2]2/AgSbF6 is effective for the oxidat
- Yoshimoto, Risa,Morisaka, Hideaki,Usuki, Yoshinosuke,Shibata, Yu,Tanaka, Ken,Satoh, Tetsuya
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supporting information
p. 1481 - 1483
(2020/12/31)
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- Tandem Photoredox Catalysis: Enabling Carbonylative Amidation of Aryl and Alkylhalides
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We report a new visible-light-mediated carbonylative amidation of aryl, heteroaryl, and alkyl halides. A tandem catalytic cycle of [Ir(ppy)2(dtb-bpy)]+ generates a potent iridium photoreductant through a second catalytic cycle in the presence of DIPEA, which productively engages aryl bromides, iodides, and even chlorides as well as primary, secondary, and tertiary alkyl iodides. The versatile in situ generated catalyst is compatible with aliphatic and aromatic amines, shows high functional-group tolerance, and enables the late-stage amidation of complex natural products.
- Connell, Timothy U.,Forni, José A.,Micic, Nenad,Polyzos, Anastasios,Weragoda, Geethika
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supporting information
p. 18646 - 18654
(2020/08/21)
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- N-acylcarbazole as a selective transamidation reagent
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N-acylation reaction offers an opportunity to develop an efficient synthesis of amide group-containing molecules. We found that N-acyl carbazoles showed remarkable selectivity in transamidation. Sterically less hindered primary amines are selectively acylated with N-acyl carbazoles without any additives. Various functional groups such as alcohol, phenol, indole, and aniline moieties are tolerated under mild conditions. The synthetic utility was displayed in one-pot synthesis of an N-acyl polyamine natural product. The terminal amines of spermidine were selectively benzoylated with N-benzoyl carbazole, followed by acetylation reaction accomplished the total synthesis in a highly efficient manner.
- Kang, Bubwoong,Kuse, Masaki,Okamura, Hironori,Sakai, Asumi,Satoh, Tetsuya,Shinada, Tetsuro,Yasuno, Yoko
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p. 993 - 999
(2020/09/22)
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- An unprecedented cobalt-catalyzed selective aroylation of primary amines with aroyl peroxides
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A novel and facile cobalt-catalyzed selective aroylation of primary amines with aroyl peroxides was developed for the synthesis of aryl amides. It was unprecedented that C[sbnd]N bond formation product was selectively generated without the common N[sbnd]O bond formation product. Aroyl peroxides act as the sole aroylation reagent without additional base or oxidant. The reactions proceeded under mild conditions and showed broad substrates scope with a series of primary amines and aroyl peroxides.
- Li, Dong,Li, Jiale,Li, Juanjuan,Yuan, Songdong,Zhang, Qian
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supporting information
(2020/09/16)
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- σ-Bond Hydroboration of Cyclopropanes
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Hydroboration of alkenes is a classical reaction in organic synthesis in which alkenes react with boranes to give alkylboranes with subsequent oxidation resulting in alcohols. The double bond (π-bond) of alkenes can be readily reacted with boranes owing to its high reactivity. However, the single bond (σ-bond) of alkanes has never been reacted. To pursue the development of σ-bond cleavage, we selected cyclopropanes as model substrates since they present a relatively weak σ-bond. Herein, we describe an iridium-catalyzed hydroboration of cyclopropanes, resulting in β-methyl alkylboronates. These unusually branched boronates can be derivatized by oxidation or cross-coupling chemistry, accessing "designer"products that are desired by practitioners of natural product synthesis and medicinal chemistry. Furthermore, mechanistic investigations and theoretical studies revealed the enabling role of the catalyst.
- Arifin,Itami, Kenichiro,Kato, Hiroki,Kobayashi, Chisa,Kondo, Hiroki,Matsushita, Kaoru,Miyamura, Shin,Yamaguchi, Junichiro,Yokogawa, Daisuke
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supporting information
p. 11306 - 11313
(2020/07/13)
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- Pyridine-Enabled C-N Bond Activation for the Rapid Construction of Amides and 4-Pyridylglyoxamides by Cooperative Palladium/Copper Catalysis
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A pyridine-enabled C-N bond activation of peptidomimetics employing cooperative palladium/copper catalysis in water is developed. Diverse amides and 4-pyridylglyoxamides are simultaneously synthesized through two steps from commercially available materials in a rapid, environmentally friendly, and high atom-economical manner.
- Song, Liangliang,Claessen, Sander,Van Der Eycken, Erik V.
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p. 8045 - 8054
(2020/07/15)
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- Triethyl Phosphite/Benzoyl Peroxide Mediated Reductive Dealkylation of O-Benzoylhydroxylamines: A Cascade Synthesis of Secondary Amides
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A new triethyl phosphite/benzoyl peroxide (BPO) mediated system has been developed for the synthesis of secondary amides with good to excellent yields in a single step. This unprecedented cascade process involves sequential reduction of N–O bond and benzoylation followed by dealkylation of N–C bond of O-benzoylhydroxylamines (O-BHA). The methodology is versatile as it tolerates a variety of aromatic and aliphatic O-BHA as substrates to access secondary amides.
- Aegurla, Balakrishna,Mandle, Ram D.,Shinde, Prasad G.,Parit, Ratan S.,Kamble, Sanjay P.,Sudalai, Arumugam,Senthilkumar, Beeran
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supporting information
p. 4235 - 4238
(2020/07/04)
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- Rhodium-Catalyzed Addition of Organozinc Iodides to Carbon-11 Isocyanates
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Amides were prepared using rhodium-catalyzed coupling of organozinc iodides and carbon-11 (11C, t1/2 = 20.4 min) isocyanates. Nonradioactive isocyanates and sp3 or sp2 organozinc iodides generated amides in yields of 13%-87%. Incorporation of cyclotron-produced [11C]CO2 into 11C-amide products proceeded in yields of 5%-99%. The synthetic utility of the methodology was demonstrated through the isolation of [11C]N-(4-fluorophenyl)-4-methoxybenzamide ([11C]6g) with a molar activity of 267 GBq μmol-1 and 12% radiochemical yield in 21 min from the beginning of synthesis.
- Fouad, Moustafa H.,Ismailani, Uzair S.,Mair, Braeden A.,Munch, Maxime,Rotstein, Benjamin H.
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p. 2746 - 2750
(2020/04/16)
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- IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
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An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
- Talukdar, Ranadeep
-
supporting information
p. 5303 - 5308
(2020/04/17)
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- Direct synthesis of secondary amides from ketones through Beckmann rearrangement using O-(mesitylsulfonyl)hydroxylamine
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The Beckmann rearrangement is a versatile method for the preparation of secondary amides from ketones via oxime intermediates and has been widely used in the synthesis of bioactive natural products and pharmaceuticals. Herein, we have developed a highly efficient direct method for the preparation of secondary amides and lactams from ketones using O-(mesitylsulfonyl)hydroxylamine (MSH). The reactions proceed rapidly at room temperature under mild condition without requiring any additive, and tolerate multiple functional groups. A simple aqueous work-up often furnished the products in excellent yield with high purity.
- Chandra, Dinesh,Verma, Saumya,Pandey, Chandra Bhan,Yadav, Ajay K.,Kumar, Puneet,Tiwari, Bhoopendra,Jat, Jawahar L.
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supporting information
(2020/03/23)
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- Electrophilic Activation of Amides for the Preparation of Polysubstituted Pyrimidines
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In this article we describe the straightforward synthesis of polysubstituted pyrimidines by electrophilic activation of secondary amides in the presence of alkynes. An unusual mechanistic detour leading to pyridine derivatives as products is also presente
- Stopka, Tobias,Adler, Pauline,Hagn, Gerhard,Zhang, Haoqi,Tona, Veronica,Maulide, Nuno
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supporting information
p. 194 - 202
(2019/01/04)
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- Chemoselective Synthesis of α-Amino-α-cyanophosphonates by Reductive Gem-Cyanation-Phosphonylation of Secondary Amides
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A novel approach to α-amino-α-cyanophosphonates has been developed. The method features a Tf2O-mediated reductive geminal cyanation/phosphonylation of secondary amides. Mild reaction conditions, high bond-forming efficiency, inexpensive readily available starting materials, and good to excellent yields with wide functional group compatibility constitute the main advantages of this method. The protocol can be run on a gram scale.
- Chen, Ting-Ting,Wang, Ai-E,Huang, Pei-Qiang
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supporting information
p. 3808 - 3812
(2019/05/24)
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- Tf2O-Mediated Intermolecular Coupling of Secondary Amides with Enamines or Ketones: A Versatile and Direct Access to β-Enaminones
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Based on the Tf2O-mediated intermolecular reaction of secondary amides with enamines derived from ketones, a novel approach to β-enaminones has been developed. The reaction is widely functional group tolerant and highly chemoselective. In the presence of 4 ? molecular sieves, the method can be extended to the one-pot condensation of secondary amides with ketones for NH β-enaminones synthesis.
- Liu, Yong-Peng,Zhu, Cheng-Jie,Yu, Cun-Cun,Wang, Ai-E,Huang, Pei-Qiang
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supporting information
p. 7169 - 7174
(2019/11/16)
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- FeCl2·4H2O catalyzed ritter reaction with nitriles and halohydrocarbons
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An efficient and inexpensive synthesis of N-substituted amides from the Ritter reaction of nitriles with various halohydrocarbons catalyzed by FeCl2·4H2O is described. FeCl2·4H2O economically efficiently catalyzed the Ritter reaction under solvent-free conditions. A range of halohydrocarbons (benzyl, tert-butyl and sec-alkyl halohydrocarbons) were coupled with nitriles to provide the corresponding amides in high to excellent yields.
- Feng, Cheng-Liang,Yin, Gui-Bo,Yan, Bin,Chen, Jun-Qing,Ji, Min
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p. 345 - 353
(2019/02/12)
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- Catalyst-Free, Metal-Free, and Chemoselective Transamidation of Activated Secondary Amides
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A simple protocol, which is catalyst-free, metal-free, and chemoselective, for transamidation of activated secondary amides in ethanol as solvent under mild conditions is reported. A wide range of amines, amino acids, amino alcohols, and the substituents, which are problematic in catalyzed transamidation, are tolerated in this methodology. The transamidation reaction was successfully extended to water as the medium as well. The present methodology appears to be better than the other catalyzed transamidations reported recently.
- Ramkumar, Rajagopal,Chandrasekaran, Srinivasan
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p. 921 - 932
(2019/02/10)
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- Tert -Butyl nitrite promoted transamidation of secondary amides under metal and catalyst free conditions
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A mild and efficient method is demonstrated for the transamidation of secondary amides with various amines including primary, secondary, cyclic and acyclic amines in the presence of tert-butyl nitrite. The reaction proceeds through the N-nitrosamide intermediate and provides the transamidation products in good to excellent yields at room temperature. Moreover, the developed methodology does not require any catalyst or additives.
- Sureshbabu, Popuri,Azeez, Sadaf,Chaudhary, Priyanka,Kandasamy, Jeyakumar
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p. 845 - 850
(2019/01/30)
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- Isoindolinone Synthesis: Selective Dioxane-Mediated Aerobic Oxidation of Isoindolines
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N-Alkyl and N-aryl-isoindolinones were prepared by a dioxane-mediated oxidation of isoindoline precursors. The transformation exhibits unique chemoselectivity for isoindonlines. A chiral tertiary (3°)-benzylic position was not racemized during oxidation, and methyl indoprofen was prepared by late stage oxidation. Mechanistic studies suggest a selective H atom transfer, which avoids many known oxidation (by-)products of isoindolinones.
- Thapa, Pawan,Corral, Esai,Sardar, Sinjinee,Pierce, Brad S.,Foss, Frank W.
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p. 1025 - 1034
(2019/01/24)
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- Generation of alkyl radicals from alkylsilyl peroxides and their applications to C-N or C-O bond formations
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This article describes a novel method for the generation of alkyl radicals from alkylsilyl peroxides and their applications to the Cu-catalyzed mono-N-alkylation of amides or arylamines, and to the O-alkylation of carboxylic acids. The use of alkylsilyl peroxides as alkyl radical sources includes the following synthetic advantages: i) various alkylsilyl peroxides can be readily synthesized from the corresponding alcohols and be stored at bench, and ii) a variety of alkyl radicals can be generated efficiently under mild conditions.
- Sakurai, Shunya,Kato, Terumasa,Sakamoto, Ryu,Maruoka, Keiji
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p. 172 - 179
(2018/12/11)
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- Metal-Free Transamidation of Secondary Amides by N-C Cleavage
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Transamidation reactions represent a fundamental chemical process involving conversion of one amide functional group into another. Herein, we report a facile, highly chemoselective method for transamidation of N-tert-butoxycarbonylation (N-Boc) activated secondary amides that proceeds under exceedingly mild conditions in the absence of any additives. Because this reaction is performed in the absence of metals, oxidants, or reductants, the reaction tolerates a large number of useful functionalities. The reaction is compatible with diverse amides and nucleophilic amines, affording the transamidation products in excellent yields through direct nucleophilic addition to the amide bond. The utility of this methodology is highlighted in the synthesis of Tigan, a commercial antiemetic, directly from the amide bond. We expect that this new metal-free transamidation will have broad implications for the development of new transformations involving direct nucleophilic addition to the amide bond as a key step.
- Rahman, Md. Mahbubur,Li, Guangchen,Szostak, Michal
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p. 12091 - 12100
(2019/10/11)
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- Direct Transformation of Arylamines to Aryl Halides via Sodium Nitrite and N-Halosuccinimide
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A one-pot universal approach for transforming arylamines to aryl halides via reaction with sodium nitrite (NaNO2) and N-halosuccinimide (NXS) in DMF at room temperature under metal- and acid-free condition is described. This new protocol that is complementary to the Sandmeyer reaction, is suggested to involve the in situ generation of nitryl halide induce nitrosylation of aryl amine to form the diazo intermediate which is halogenated to furnish the aryl halide.
- Mukhopadhyay, Sushobhan,Batra, Sanjay
-
supporting information
p. 14622 - 14626
(2018/09/21)
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- Towards a Sequential One-Pot Preparation of 1,2,3-Benzotriazin-4(3H)-ones Employing a Key Cp*Co(III)-catalyzed C?H Amidation Step
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1,2,3-benzotriazin-4(3H)-one derivatives have been recognised for their potential application as pesticides and pharmaceuticals and new methodologies for their preparation, starting from readily accessible reagents would therefore be an attractive proposition. A wide range of differently substituted benzamides are readily available, which provide an excellent substrate scaffold for the application of direct C?H functionalization protocols. In this context, herein we report the use of a Cp*Co(III) catalyst for the amidation of these benzamides, using 1,4,2-dioxazol-5-ones as amidating agent. The isolable intermediate 2-acetamido benzamide products can thereafter be converted to the desired 1,2,3-benzotriazin-4(3H)-one derivatives through the use of tert-butyl nitrite under mild conditions. It was found to be possible to perform the second step with the crude reaction mixture obtained from the initial C?H amidation step, leading to the overall development of a facile one-pot procedure for the preparation of a range of substituted 1,2,3-benzotriazin-4(3H)-one derivatives, requiring only 5 hours of reaction time, which is also applicable on a gram scale. In addition, the key Cp*Co(III)-catalyzed C?H amidation step has been studied by DFT calculations in order to fully elucidate the mechanism. (Figure presented.).
- Chirila, Paula G.,Skibinski, Lauren,Miller, Keith,Hamilton, Alex,Whiteoak, Christopher J.
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supporting information
p. 2324 - 2332
(2018/04/30)
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- Visible-Light-Driven Oxidation of N -Alkylamides to Imides Using Oxone/H 2 O and Catalytic KBr
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Imides are prepared conveniently by visible-light-driven oxidations of various N -alkylamides under mild conditions. The majority of the reactions proceed efficiently by using Oxone as the oxidant in the presence of a catalytic amount of KBr in H 2 O/CH 2 Cl 2 under irradiation by an 8 W white LED at room temperature. Experimental studies suggest that an imine, obtained from the substrate amide via a radical process, is the key intermediate.
- Mei, Chong,Hu, Yixin,Lu, Wenjun
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supporting information
p. 2999 - 3005
(2018/05/25)
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- Convenient synthesis of amides by Zn(ClO4)2·6H2O catalysed Ritter reaction with nitriles and halohydrocarbons
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A convenient and high yielding procedure for the synthesis of amides by the Ritter reaction of nitriles and halohydrocarbons in the presence of Zn(ClO4)2·6H2O as a highly stable, effective and available catalyst is described.
- Feng, Chengliang,Yin, Guibo,Yan, Bin,Chen, Junqing,Ji, Min
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supporting information
p. 383 - 386
(2018/08/21)
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- Regio- and Stereoselective Chan-Lam-Evans Enol Esterification of Carboxylic Acids with Alkenylboroxines
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Efficient and scalable Cu(II)-mediated enol esterification methodology of carboxylic acids from alkenyl boroxines and boronic acids is presented. The reaction shows a wide scope in aliphatic and aromatic carboxylic acids in combination with several alkenyl boroxines. In the case of 2-substituted alkenyl boroxines the double bond configuration was fully retained in the enol ester product. Also N-hydroxyimides and imides could be transformed in the respective amidooxy vinyl enol ethers and vinyl enamides. Finally, with the exception of methionine, all other 19 canonical amino acids showed their compatibility to give the enol esters in a stereoselective fashion. (Figure presented.).
- Steemers, Luuk,Wijsman, Linda,van Maarseveen, Jan H.
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supporting information
p. 4241 - 4245
(2018/10/02)
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- Fe(ClO 4) 3 ·h 2 O-Catalyzed Ritter Reaction: A Convenient Synthesis of Amides from Esters and Nitriles
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An efficient and inexpensive synthesis of N-substituted amides from the Ritter reaction of nitriles with esters catalyzed by Fe(ClO 4) 3 ·H 2 O is described. Fe(ClO 4) 3 ·H 2 O is an economically efficient catalyst for the Ritter reaction under solvent-free conditions. Reactions of a range of esters (benzyl, sec-alkyl, and tert-butyl esters) with nitriles (primary, secondary, tertiary, and aryl nitriles) were performed to provide the corresponding amides in high to excellent yields.
- Feng, Chengliang,Yan, Bin,Yin, Guibo,Chen, Junqing,Ji, Min
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p. 2257 - 2264
(2018/10/20)
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- Transamidation of: N -acyl-glutarimides with amines
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The development of new transamidation reactions for the synthesis of amides is an important and active area of research due to the central role of amide linkage in various fields of chemistry. Herein, we report a new method for transamidation of N-acyl-glutarimides with amines under mild, metal-free conditions that relies on amide bond twist to weaken amidic resonance. A wide range of amines and functional groups, including electrophilic substituents that would be problematic in metal-catalyzed protocols, are tolerated under the reaction conditions. Mechanistic experiments implicate the amide bond twist, thermodynamic stability of the tetrahedral intermediate and leaving group ability of glutarimide as factors controlling the reactivity of this process. The method further establishes the synthetic utility of N-acyl-glutarimides as bench-stable, twist-perpendicular, amide-based reagents in acyl-transfer reactions by a metal-free pathway. The origin of reactivity of N-acyl-glutarimides in metal-free and metal-catalyzed processes is discussed and compared.
- Liu, Yongmei,Achtenhagen, Marcel,Liu, Ruzhang,Szostak, Michal
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supporting information
p. 1322 - 1329
(2018/03/06)
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- Base-promoted amide synthesis from aliphatic amines and ynones as acylation agents through C-C bond cleavage
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A new protocol for the synthesis of amides via base-promoted cleavage of the C(sp)-C(CO) bond of ynones with aliphatic primary and secondary amines under transition-metal-, ligand-, and oxidant-free conditions has been developed. This method exhibits a wide substrate scope, high functional group tolerance and exclusive chemoselectivity, as well as mild reaction conditions.
- Cheng, Guolin,Lv, Weiwei,Kuai, Changsheng,Wen, Si,Xiao, Shangyun
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supporting information
p. 1726 - 1729
(2018/02/21)
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- Synthesis of Benzamide Derivatives by the Reaction of Arenes and Isocyanides through a C-H Bond Activation Strategy
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A carbon-carbon bond formation reaction between isocyanides and benzene derivatives is reported. In contrast to traditional cross-coupling reactions, which require aryl halides or pseudohalides, we use a palladium catalyst to generate the aryl-palladium through C-H bond activation of arenes. This method offers an attractive approach to a range of benzamides from readily accessible benzene derivatives.
- Khalaj, Mehdi,Taherkhani, Mahboubeh,Mousavi-Safavi, Seyed Mahmoud,Akbari, Jafar
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- Continuous flow reaction system for the synthesis of 2,2,2-trichloroacetophenone derivatives and its application
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A continuous flow reaction system was developed for the synthesis of 2,2,2-trichloroacetophenone derivatives. When aryl propiolic acids and water were mixed with trichloroisocyanuric acid in DMF at 5 °C, the 2,2,2-trichloroacetophenone derivatives were formed within 5 min with good yields. In addition, the resulting mixture was flowed to react with amines to give the corresponding benzamide. This flow reaction system provided higher yields within shorter times than the batch reaction system.
- Ko, Byeng Ha,Yu, Subeen,Song, Kwang Ho,Lee, Sunwoo
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p. 991 - 994
(2018/02/14)
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- Direct and Catalytic Amide Synthesis from Ketones via Transoximation and Beckmann Rearrangement under Mild Conditions
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The Br?nsted acid-catalyzed synthesis of secondary amides from ketones under mild conditions is described via transoximation and Beckmann rearrangement using O-protected oximes as more stable equivalents of explosive O-protected hydroxylamines. This methodology could be applied to highly rearrangement-selective amide synthesis from α-branched alkyl aryl ketones and performed on a 1-g scale. The presence of water is essential for this reaction, and its role was clarified by isotope-labeling experiments.
- Hyodo, Kengo,Hasegawa, Genna,Oishi, Naoki,Kuroda, Kazuma,Uchida, Kingo
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supporting information
p. 13080 - 13087
(2018/11/02)
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- Electrophilic Activation of Carboxylic Anhydrides for Nucleophilic Acylation Reactions
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Nucleophilic acylation of symmetrical carboxylic anhydrides has inherited limitation of reaction efficiency along with relatively poor reactivity. Traditionally, one equivalent carboxylic acid is generated during nucleophilic acylation of a symmetrical anhydride, which always limits the yield of final product to 50percent or less. This is a major drawback, which discourages the use of anhydrides for laboratory or industrial applications. Electrophilic activation of carboxylic anhydride using methanesulfonyl chloride is found to be an efficient method for nucleophilic acylation, which increases product yield by restricting the formation of corresponding acid as a side product. The developed protocol found to be a mild and high yielding methodology for one-pot nucleophilic acylation of carboxylic anhydrides with several type of N- and S-nucleophiles demonstrating appreciable functional group tolerance.
- Kumar, Varun,Kumar, Yashwant,Lal Meena, Chhuttan,Mahajan, Dinesh,Rana, Anil,Sharma, Nidhi
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p. 3902 - 3910
(2018/09/29)
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- An Annulative Synthetic Strategy for Building Triphenylene Frameworks by Multiple C?H Bond Activations
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C?H activation is a versatile tool for appending aryl groups to aromatic systems. However, heavy demands on multiple catalytic cycle operations and site-selectivity have limited its use for graphene segment synthesis. A Pd-catal- yzed one-step synthesis of functionalized triphenylene frameworks is disclosed, which proceeds by 2- or 4-fold C?H arylation of unactivated benzene derivatives. A Pd2(dibenzylideneacetone)3 catalytic system, using cyclic diaryliodonium salts as π-extending agents, leads to site-selective inter- and intramolecular tandem arylation sequences. Moreover, N-substituted triphenylenes are applied to a field-effect transistor sensor for rapid, sensitive, and reversible alcohol vapor detection.
- Mathew, Bijoy P.,Yang, Hyun Ji,Kim, Joohee,Lee, Jae Bin,Kim, Yun-Tae,Lee, Sungmin,Lee, Chang Young,Choe, Wonyoung,Myung, Kyungjae,Park, Jang-Ung,Hong, Sung You
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supporting information
p. 5007 - 5011
(2017/04/24)
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- Unmasking Amides: Ruthenium-Catalyzed Protodecarbonylation of N-Substituted Phthalimide Derivatives
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The unprecedented transformation of a wide range of synthetically appealing phthalimides into amides in a single-step operation has been achieved in high yields and short reaction times using a ruthenium catalyst. Mechanistic studies revealed a unique, homogeneous pathway involving five-membered ring opening and CO2 release with water being the source of protons.
- Yuan, Yu-Chao,Kamaraj, Raghu,Bruneau, Christian,Labasque, Thierry,Roisnel, Thierry,Gramage-Doria, Rafael
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supporting information
p. 6404 - 6407
(2017/12/08)
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- Atom economical synthesis of: N -alkylbenzamides via the iron(III) sulfate catalyzed rearrangement of 2-alkyl-3-aryloxaziridines in water and in the presence of a surfactant
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A green and mild synthetic route to N-alkylbenzamides involves eco-friendly one pot synthesis of 2-alkyl-3-aryloxaziridines from N-alkylamines and benzaldehydes followed by iron(iii) sulfate catalyzed rearrangement to the corresponding amides in water as the solvent and in the presence of sodium dodecyl sulfate as the surfactant. This green approach affords N-alkylbenzamides in high overall yields under simple and minimum manipulation.
- Kra?em, Jamil,Ollevier, Thierry
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p. 1263 - 1267
(2017/08/15)
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- Transformation of aldehydes or alcohols to amides at room temperature under aqueous conditions
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A novel and efficient method for the synthesis of amide has been developed. The reactions proceeded smoothly under aqueous conditions at room temperature and generated the corresponding products in good to excellent yields. It is worth noting that alkyl amines which did not react in known approaches are well tolerated in our system.
- Dong, Dao-Qing,Hao, Shuang-Hong,Zhang, Hui,Wang, Zu-Li
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p. 1597 - 1599
(2017/07/17)
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