- Synthesis of Amino-Substituted α- And δ-Carbolines via Metal-Free [2 + 2 + 2] Cycloaddition of Functionalized Alkyne-Nitriles with Ynamides
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A metal-free [2 + 2 + 2] cycloaddition of alkyne-cyanamides or ynamide-nitriles with ynamides is described for the efficient synthesis of amino-substituted α- and δ-carbolines. This novel methodology is environmentally friendly and allows for highly regioselective access to carboline derivatives in good to excellent yields with wide functional group tolerance.
- Zhang, Jingyi,Guo, Meichao,Chen, Yajuan,Zhang, Shuangshuang,Wang, Xiao-Na,Chang, Junbiao
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- Synthesis of sulfonamides promoted by alkyl iodide via a hypervalent iodine intermediate
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A new method for the preparation of sulfonamides from sodium sulfinates and amines is developed. A stoichiometric amount of m-chloroperbenzoic acid as oxidant and a catalytic amount of 1-iodopropane provides the corresponding sulfonamides in good yields under mild reaction conditions. In this protocol, 1-iodopropane is first oxidized by m-chloroperbenzoic acid into the corresponding hypervalent iodine intermediate iodosylpropane, which is highly unstable and decomposes at once to form hypoiodous acid. Then, the following reaction of the generated active hypoiodous acid with sodium sulfinates and amines results in the corresponding sulfonamides.
- Zhou, Zhongshi,He, Xuehan
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- Palladium-Catalyzed Oxidative Sulfamidation: A Stereoselective Synthesis for Enesulfonamides
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A palladium-catalyzed protocol involving oxidative C–H sulfamidation of electron-deficient terminal alkenes is described for the stereoselective synthesis of Z-enesulfonamides. The possible intramolecular hydrogen bonding between the sulfamido proton (SO2N–H) and the carbonyl oxygen (C=O) of the ester group provides extra stability to the resulting alkyl-palladium complex as well as to the transition state. Notably, this reaction operates at room temperature under ligand-free conditions and does not require any inert atmosphere or dry solvent or expensive terminal oxidant. The present protocol enables the stereoselective synthesis of Z-enesulfonamides from the primary sulfonamides and of E-enesulfonamides from N-substituted sulfonamides. Furthermore, the selective deallylation of sulfonamides in the presence of an N-benzyl group was performed under the above reaction conditions. (Figure presented.).
- Panda, Niranjan,Yadav, Sushree Arpitabala,Giri, Santanab
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- PhI(OAc)2-mediated synthesis of propargylic N, O-acetals by 1, 2-addition of alcohols to allenamides
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A hypervalent iodine mediated electrophilic activation of allenamides was investigated and propargylic N, O-acetals were prepared in moderate to good yields. By the use of PhI(OAc)2 as oxidant and alcohol as both nucleophile and solvent, allenamides were converted into propargylic N, O-acetals via 1, 2-addition of alcohol to the sulfimide ion intermediate, and no 1, 4-adducts were found.
- Huang, Ruohe,Peng, Guo,Wang, Weixiang,Xu, Pengyu,Yu, Hui
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- Observation of a Photogenerated Rh2 Nitrenoid Intermediate in C-H Amination
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Rh2-catalyzed C-H amination is a powerful method for nitrogenating organic molecules. While Rh2 nitrenoids are often invoked as reactive intermediates in these reactions, the exquisite reactivity and fleeting lifetime of these species has precluded their observation. Here, we report the photogeneration of a transient Rh2 nitrenoid that participates in C-H amination. The developed approach to Rh2 nitrenoids, based on photochemical cleavage of N-Cl bonds in N-chloroamido ligands, has enabled characterization of a reactive Rh2 nitrenoid by mass spectrometry and transient absorption spectroscopy. We anticipate that photogeneration of metal nitrenoids will contribute to the development of C-H amination catalysis by providing tools to directly study the structures of these critical intermediates.
- Das, Anuvab,Maher, Andrew G.,Telser, Joshua,Powers, David C.
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- Acidity of cyclic sulfamates: Study of substituted 1,2,3-benzoxathiazole 2,2,-dioxides and theoretical investigation of the effect of conformation on acidity
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Sulfamate 1b, 5-nitro-3-(4-toluenesulfonyl)-1,2,3-benzoxathiazole 2,2- dioxide, was treated with various nucleophiles: imidazole, benzylamine, tert-butylamine, sodium azide, potassium fluoride, pyridine, and sodium hydroxide. The first five attacked the exocyclic (tosyl) sulfur atom. No reaction was observed with the pyridine. The hydroxide ion attacked the endocyclic sulfur atom leading to opening of the benzoxathiazole ring. Several N-unsubstituted cyclic sulfamates, X-3H-1,2,3-benzoxathiazole 2,2-dioxides (2a, X = 5-H; 2b, X = 5-NO2; 2c, X = 5-Me; 2d, X = 5-Br; 2e, X = 5-Cl; 2f, X = 6-NO2; 2g, X = 5,6-Cl,Cl) and the naphtho-fused cyclic sulfamate (2h), were prepared by treatment of the respective N-tosyl compounds (1a-h) with sodium azide or potassium fluoride. The pK(a) values for these compounds were determined by potentiometric titration in 60% v/v EtOH/H2O. A Hammett plot using σ(m) for 2a-e, σ(p) for 2f, and both σ(m) and σ(p) for 2g gave a ρ = 2.74. Ab initio calculations were done using sulfamic acid as a simple sulfamate model to test the effect of the geometry changes on pK(a) The calculations showed that the sulfamate with the ringlike geometry should be 3.6 pK(a) units more acidic than the acyclic sulfamate. This overall change was broken down into three factors affecting the pK(a). The N-S bond rotation accounted for a change of 0.22 units, O-S bond rotation for 2.03 units, and ring strain for 1.36 units.
- Andersen,Kociolek
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- A novel approach for the synthesis of alkyl and aryl sulfonamides
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A novel approach for the synthesis of alkyl and aryl sulfonamides by the reaction of sulfonic acids, isocyanides and water in dichloromethane is reported at ambient temperature in excellent yields within 20 min. To the best of our knowledge this is the first report on the synthesis of this biologically important family using easily available sulfonic acids and isocyanides.
- Shaabani, Ahmad,Soleimani, Ebrahim,Hossein Rezayan, Ali
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- Two-step 1,2-shifts by β-cleavage of carbenium ions and recombination in friedel-crafts reactions of 2-ferf-butyl-l-tosylaziridines
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Alcl3-induced ring cleavage of two 2-tert-butyl-l-tosylaziridines in benzene (PhH) or anisole (AnH) generates carbenium ions (CIs). Subsequent neopentyl rearrangement forms CIs 3a,b, whose β-cleavage generates +CH2NTsAlCl3- (14) and an alkene. The intermediate 14 can recombine with the alkene at either C=C carbon, resulting in a reversal of the cleavage (3a,b) or in a formal 1,2shift (CIs 12a,b). AnH rapidly removes 14 from these interconverting systems by formation of a methoxybenzylamide species that undergoes fragmentation into TsNHAlCl3- and methoxybenzyl cation, which gives dianisylmethane (main product). PhH reacts slowly with 14, leaving CIs 3a,b and 12a,b more time for other reactions. Unreacted 14 can even be trapped by AnH at the end of a PhH run. Protonation of each alkene forms N-free CIs that react with PhH and AnH. Replacing tosyl in one of the aziridines by benzoyl makes the β-cleavage markedly slower than both the classic phenyl shift and the internal trapping of CIs.
- Bellos, Konstantinos,Stamm, Helmut
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- Synthesis of polymer-bound 4-acetoxy-3-phenylbenzaldehyde derivatives: Applications in solid-phase organic synthesis
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(Chemical Equation Presented) Aminomethyl polystyrene resin was reacted with 4-(5′-formyl-2′-hydroxyphenyl)benzoic acid and 4-(5′-formyl-2′-hydroxyphenyl)phenyl propionic acid, respectively, in the presence of 1-hydroxybenzotriazole and 1,3-diisopropylcarbodiimide to yield polymer-bound benzaldehydes. The phenolic group in resins was acetylated with acetic anhydride to afford two polymer-bound 4-acetoxybenzaldehydes. The reductive amination of polymer-bound linkers by amines and sodium triacetoxyborohydride, followed by sulfonylation with arylsulfonyl chloride derivatives in the presence of pyridine and the cleavage with TFA/DCM/H 2O, produced pure sulfonamides.
- Kumar, Anil,Ye, Guofeng,Ahmadibeni, Yousef,Parang, Keykavous
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- Selective diethylzinc reduction of imines in the presence of ketones catalyzed by Ni(acac)2
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(Chemical Equation Presented) A selective reduction method of an electronically deficient imine in the presence of ketone was developed by employing Et2Zn and 5 mol % of Ni(acac)2. The method was applied in the reduction of SS-tert-butanesulfinyl ketimines 1 to afford amines 2 in 23-92% yields and 73:27 to 98:2 diastereoselectivities. A plausible mechanism was proposed on the basis of an NMR study.
- Xiao, Xue,Wang, Haowei,Huang, Zhiyan,Yang, Jun,Bian, Xiaoxia,Qin, Yong
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- Cyclohexane and benzene amination by catalytic nitrene insertion into C-H bonds with the copper-homoscorpionate catalyst TpBr3Cu(NCMe)
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The complex TpBr3Cu(NCMe) catalyzes, at room temperature, the insertion of a nitrene group from PhINTs into the carbon-hydrogen bond of cyclohexane and benzene, as well as into the primary C-H bonds of the methyl groups of toluene and mesitylene, in moderate to high yield. Copyright
- Diaz-Requejo, M. Mar,Belderrain, Tomas R.,Nicasio, M. Carmen,Trofimenko, Swiatoslaw,Perez, Pedro J.
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- Efficient chiral amidophosphine ligand for copper-catalyzed asymmetric addition of diethylzinc to N-sulfonylimines
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Structure study of a chiral amidophosphine ligand for copper-catalyzed asymmetric addition reaction of diethylzinc with the N-tosylimine reached to the new chiral phosphine bearing the bulky substituent on the pyrrolidine ring, which significantly improved catalytic performance to give the adduct in 96% yield and 93% ee after 3 h.
- Nagai, Kazushige,Fujihara, Hidetaka,Kuriyama, Masami,Yamada, Ken-ichi,Tomioka, Kiyoshi
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- Direct aminoalkylation of cycloalkanes through dimethylzinc-initiated radical process
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Cycloalkyl radicals were directly generated from cycloalkanes via C-H bond cleavage by the action of dimethylzinc-air and underwent an addition reaction with N-tosylimines, giving aminoalkylation products in fair to high yields.
- Yamada, Ken-Ichi,Yamamoto, Yasutomo,Maekawa, Masaru,Chen, Jingbo,Tomioka, Kiyoshi
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- Dimethylzinc-mediated alkynylation of imines
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The treatment of various aromatic and aliphatic aldimines with a mixture of a terminal alkyne and a commercially available dimethylzinc solution in toluene yields the corresponding protected propargylic amines in moderate to excellent yields. The reaction
- Zani, Lorenzo,Alesi, Silvia,Cozzi, Pier Giorgio,Bolm, Carsten
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- Ligand-Controlled Regiodivergence for Catalytic Stereoselective Semireduction of Allenamides
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Ligand-controlled regiodivergence has been developed for catalytic semireduction of allenamides with excellent chemo- and stereocontrol. This system also provides an example of catalytic regiodivergent semireduction of allenes for the first time. The divergence of the semireduction is enabled by ligand switch with the same palladium pre-catalyst under operationally simple and mild conditions. Monodentate ligand XPhos exclusively promotes selective 1,2-semireduction to afford allylic amides, while bidentate ligand BINAP completely switched the regioselectivity to 2,3-semireduction, producing (E)-enamide derivatives.
- Hajiloo Shayegan, Mojtaba,Li, Zhong-Yuan,Cui, Xin
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supporting information
(2021/12/02)
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- Chemoselective Cleavage of Acylsulfonamides and Sulfonamides by Aluminum Halides
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The chemoselective cleavage of C-N bonds of amides, sulfonamides, and acylsulfonamides by aluminum halides is described. AlCl3and AlI3display complementary reactivities toward N-alkyl and N-acyl moieties. N-Alkylacylsulfonamides, sec
- Sang, Dayong,Dong, Bingqian,Liu, Yunfeng,Tian, Juan
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p. 3586 - 3595
(2022/02/25)
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- Enantioselective Rhodium-Catalyzed Hydrogenation of (Z)-N-Sulfonyl-α-dehydroamido Boronic Esters
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Highly enantioselective rhodium-catalyzed hydrogenation of (Z)-N-sulfonyl-α-dehydroamido boronic esters is realized for the first time using a JosiPhos-type ligand. This method has enabled convenient synthesis of a series of enantio-enriched N-sulfonyl-α-amido boronic esters in good yields and excellent enantioselectivities (up to 99% ee).
- Li, Zhenya,Xu, Ronghua,Guo, Huichuang,Yang, He,Xu, Guangqing,Shi, Enxue,Xiao, Junhua,Tang, Wenjun
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supporting information
p. 714 - 719
(2022/01/20)
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- A new generation of terminal copper nitrenes and their application in aromatic C-H amination reactions
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Copper nitrene complexes are highly reactive species and are known as intermediates in the copper catalyzed C-H amination. In this study, three novel copper tosyl nitrene complexes were synthesized at low temperatures, stabilized with heteroscorpionate ligands of the bis(pyrazolyl)methane family. The copper nitrenes were obtained by the reaction of a copper(i) acetonitrile complex with SPhINTs in dichloromethane. We show that the ligand design has a major influence on the catalytic activity and the thermal stability of the copper nitrene complex. Not only the choice of the third N donor, but also the substituent in the 5-position of the pyrazolyl moiety, have an impact on the stability. Furthermore, the novel copper nitrene complexes were used for catalytic aziridination of styrenes and C-H amination reactions of aromatic and aliphatic substrates under mild reaction conditions. Even challenging substrates like benzene and cyclohexane were aminated with good yields. The copper nitrene complexes were characterized using UV/Vis spectroscopy, low temperature Evans NMR spectroscopy, density functional theory, domain-based local pair natural orbital coupled cluster calculations (DLPNO-CCSD(T)) and cryo-UHR mass spectrometry.
- Amarouch, Benedikt,G?bgen, Kai C.,Hoffmann, Alexander,Oster, Matthias,Sch?n, Florian,Steden, Dominik,Thomas, Fabian
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supporting information
p. 6444 - 6462
(2021/05/26)
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- Chiral bis(pyrazolyl)methane copper(I) complexes and their application in nitrene transfer reactions
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In this study, chiral bis(pyrazolyl)methane copper(I) acetonitrile complexes were applied to generate two novel terminal copper tosyl nitrene complexes with the nitrene generating agent SPhINTs in dichloromethane at low temperatures. The syntheses of the chiral bis(pyrazolyl)methane ligands are based on pulegone and camphor, members of the natural chiral pool. The chiral copper(I) acetonitrile complexes were applied as catalysts in the copper nitrene mediated aziridination reaction of different styrene derivatives and the C-H amination of various substrates. The reactions afforded good yields, but low enantiomeric excess under mild conditions. The nitrene species have been characterized with UV/Vis and EPR spectroscopy and the products of the decay by ESI mass spectrometry.
- Thomas, Fabian,Steden, Dominik,Eith, Alexander,Hoffmann, Alexander,Herres-Pawlis, Sonja
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p. 835 - 847
(2021/11/09)
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- Amide Iridium Complexes As Catalysts for Transfer Hydrogenation Reduction of N-sulfonylimine
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Sulfonamide moieties widely exist in natural products, biologically active substance, and pharmaceuticals. Here, an efficient water-soluble amide iridium complexes-catalyzed transfer hydrogenation reduction of N-sulfonylimine is developed, which can be carried out under environmentally friendly conditions, affording a series of sulfonamide compounds in excellent yields (96-98%). In comparison with organic solvents, water is shown to be critical for a high catalytic transfer hydrogenation reduction in which the catalyst loading can be as low as 0.001 mol %. These amide iridium complexes are easy to synthesize, one structure of which was determined by single-crystal X-ray diffraction. This protocol gives an operationally simple, practical, and environmentally friendly strategy for synthesis of sulfonamide compounds.
- Wen, Huiling,Luo, Nianhua,Zhu, Qianheng,Luo, Renshi
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p. 3850 - 3859
(2021/03/09)
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- Implication of a Silyl Cobalt Dihydride Complex as a Useful Catalyst for the Hydrosilylation of Imines
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Here, we describe the formation and use of silyl cobalt (III) dihydride complexes as powerful catalysts for the hydrosilylation of a variety of imines starting from a low-valent well-defined cobalt (I) complex. The reaction is efficient at low catalyst loadings with a diverse range of imines bearing various protecting groups, as well as aliphatic ketimines and quinoline. Kinetics, DFT calculations, NMR spectroscopic studies, deuteration experiments, and X-ray diffraction analyses allowed us to propose a catalytic cycle based on silyl dihydrocobalt (III) complexes performing a hydrocobaltation.
- Barbazanges, Marion,Bories, Cassandre C.,Derat, Etienne,Petit, Marc
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p. 14262 - 14273
(2021/11/27)
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- Hydrosilylation and Mukaiyama aldol-type reaction of quinolines and hydrosilylation of imines catalyzed by a mesoionic carbene-stabilized borenium ion
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Aldimines and ketimines containing electron-donating and electron-withdrawing groups can be hydrosilylated with borenium catalysts at as low as 1 mol% catalyst loading at room temperature, providing the corresponding secondary amines in excellent yields. Reactions with 2-phenylquinoline gave the 1,4-hydrosilylquinoline product selectively which can be further functionalized in a one-pot synthesis to give unique γ-amino alcohol derivatives. Control experiments suggest that the borenium ion catalyzes both the hydrosilylation and subsequent addition to the aldehyde.
- Bestvater, Brian P.,Clarke, Joshua J.,Crudden, Cathleen M.,DeJesus, Joseph F.,Devaraj, Karthik,Eisenberger, Patrick,Kojima, Ryoto
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p. 6786 - 6791
(2021/08/20)
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- Au(I)-Catalyzed Oxidative Functionalization of Yndiamides
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Yndiamides, underexplored cousins of ynamides, offer rich synthetic potential as doubly nitrogenated two carbon building blocks. Here we report a gold-catalyzed oxidative functionalization of yndiamides to access unnatural amino acid derivatives, using a wide range of nucleophiles as a source of the amino acid side chain. The transformation proceeds under mild conditions, is highly functional group tolerant, and displays excellent regioselectivity through subtle steric differentiation of the yndiamide nitrogen atom substituents.
- Tong, Zixuan,Garry, Olivia L.,Smith, Philip J.,Jiang, Yubo,Mansfield, Steven J.,Anderson, Edward A.
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supporting information
p. 4888 - 4892
(2021/06/28)
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- Cobalt-Catalyzed 1,4-Aryl Migration/Desulfonylation Cascade: Synthesis of α-Aryl Amides
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A cobalt-catalyzed 1,4-aryl migration/disulfonylation cascade applied to α-bromo N-sulfonyl amides was developed. The reaction was highly chemoselective, allowing the preparation of α-aryl amides possessing a variety of functional groups. The method was used as the key step to synthesize an alkaloid, (±)-deoxyeseroline. Mechanistic investigations suggest a radical process.
- Gillaizeau-Simonian, Nicolas,Barde, Etienne,Guérinot, Amandine,Cossy, Janine
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supporting information
p. 4004 - 4008
(2021/02/11)
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- N-Aroylsulfonamide-Photofragmentation (ASAP)-A Versatile Route to Biaryls
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The photochemical fragmentation of N-aroylsulfonamides 9 (ASAP) is a powerful method for the preparation of various biaryls. Compounds 9 are easily accessible in two steps from amines by treatment with arenesulfonyl chlorides and aroyl chlorides. Many of these compounds were prepared for the first time. The irradiation takes place in a previously developed continuous-flow reactor using inexpensive UVB or UVC fluorescent lamps. Isocyanates and sulphur dioxide are formed as the only by-products. The ASAP tolerates a variety of functional groups and is even suited for the preparation of phenylnaphthalenes and terphenyls. The ASAP mechanism was elucidated by interaction of photophysical and quantum chemical (DFT) methods and revealed a spirocyclic biradical as key intermediate.
- Wessig, Pablo,Krebs, Saskia
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supporting information
p. 6367 - 6374
(2021/09/29)
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- Synthesis of Polysubstituted Fused Pyrroles by Gold-Catalyzed Cycloisomerization/1,2-Sulfonyl Migration of Yndiamides
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Yndiamides (bis-N-substituted alkynes) are valuable precursors to azacycles. Here we report a cycloisomerization/1,2-sulfonyl migration of alkynyl-yndiamides to form tetrahydropyrrolopyrroles, unprecedented heterocyclic scaffolds that are relevant to medicinal chemistry. This functional group tolerant transformation can be achieved using Au(I) catalysis that proceeds at ambient temperature, and a thermally promoted process. The utility of the products is demonstrated by a range of reactions to functionalize the fused pyrrole core.
- Smith, Philip J.,Jiang, Yubo,Tong, Zixuan,Pickford, Helena D.,Christensen, Kirsten E.,Nugent, Jeremy,Anderson, Edward A.
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supporting information
p. 6547 - 6552
(2021/08/30)
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- Nickel-Catalyzed C(sp3)-H Functionalization of Benzyl Nitriles: Direct Michael Addition to Terminal Vinyl Ketones
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An efficient nickel(0)-catalyzed addition of benzyl nitriles to terminal vinyl ketones via C(sp3)-H functionalization has been developed. The reaction provides a novel and efficient protocol for the synthesis of α-functionalized benzyl nitriles with a wide range of structural diversity under mild reaction conditions while obviating the use of a strong base. The work might be potentially useful toward the development of an enantioselective variant using chiral nitrogen ligands.
- Zhang, Ninghui,Zhang, Chunli,Hu, Xiaoping,Xie, Xin,Liu, Yuanhong
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supporting information
p. 6004 - 6009
(2021/07/31)
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- Electrochemical C?H Amidation of Heteroarenes with N-Alkyl Sulfonamides in Aqueous Medium
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The construction of C?N bonds by free radical reactions represents a powerful synthetic approach for direct C?H amidations of arenes or heteroarenes. Developing efficient and more environmentally friendly synthetic methods for C?H amidation reactions remains highly desirable. Herein, metal-free electrochemical oxidative dehydrogenative C?H amidations of heteroarenes with N-alkylsulfonamides have been accomplished. The catalyst- and chemical-oxidant-free C?H amidation features an ample scope and employs electricity as the green and sole oxidant. A variety of heteroarenes, including indoles, pyrroles, benzofuran and benzothiophene, thereby underwent this C(sp2)?H nitrogenation. Cyclic voltammetry studies and control experiments provided evidence for nitrogen-centered radicals being directly generated under metal-free electrocatalysis.
- Zhang, Yan,Lin, Zhipeng,Ackermann, Lutz
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supporting information
p. 242 - 246
(2020/11/30)
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- Ynamides as Three-Atom Components in Cycloadditions: An Unexplored Chemical Reaction Space
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While 1,3-dipolar cycloadditions have appeared to be a fertile area for research, as attested by the numerous synthetic transformations and resulting applications that have been developed during the past 60 years, the use of neutral three-Atom components (TACs) in (3+2) cycloadditions remains comparatively sparse. Neutral TACs, however, have great synthetic potential given that their reaction with a πsystem can produce zwitterionic cycloadducts that may be manipulated for further chemistry. We report herein that ynamides, a class of carbon πsystems that has seen wide interest over the last two decades, can be used as neutral TACs in thermally induced intramolecular (3+2) cycloaddition reactions with alkynes to yield a variety of functionalized pyrroles. The transformation is proposed to occur in a stepwise manner via the intermediacy of a pyrrolium ylide, from which the electron-withdrawing group on the nitrogen atom undergoes an intramolecular 1,2-shift to produce the neutral pyrrole. This work demonstrates a yet unexplored facet of ynamide reactivity with great potential in heterocyclic chemistry.
- Campeau, Dominic,Gagosz, Fabien,Pommainville, Alice
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supporting information
p. 9601 - 9611
(2021/07/19)
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- Recurrent Approximation of Retention Parameters of N-Substituted p-Toluenesulfonamides in Reversed-Phase High Performance Liquid Chromatography for Revealing the Formation of Their Hydrates
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Abstract: Recurrent approximation of retention times in reversed-phase high performance liquid chromatography (RP-HPLC), tR(C + ΔC) = atR(C) + b, where C is the acetonitrile concentration in the eluent, and ΔC is the constant “step” of its variation, for six specially synthesized N-substituted p-toluenesulfonamides confirmed the presence of anomalies previously revealed for some complex polyfunctional organic compounds. The reason for these anomalies is the presence of sulfonamide –SO2–NH fragments in the molecules, which leads to hydration of sorbates in aqueous solutions, or, more precisely, to a change in the ratio of their non-hydrated and hydrated forms because of a shift in the equilibrium Х + Н2О $$ rightleftarrows $$ Х·Н2О (*) as a result of a change in the eluent composition. The same effect is indicated by the strong antibatic dependence of the retention indices RI(C) of all sulfonamides under study; the coefficients dRI/dC vary from –1.9 to –4.0, these values being much higher in magnitude than for compounds that do not form hydrates. Further independent evidence in favor of the transformation of sorbates due to variation of the eluent composition is the dependence of the relative absorbance Arel = A(254)/A(220) on the acetonitrile content in the eluent. This suggests changes in the chemical nature of chromophores in sulfonamide molecules depending on the equilibrium state (*).
- Kornilova, T. A.,Nikitina, D. A.,Zenkevich, I. G.
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p. 1931 - 1941
(2021/09/15)
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- Ag(I)-Catalyzed Synthesis of 2-Aminoquinolines from 1-Aminobutadiynes and Anilines
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A Ag(I)-catalyzed annulation of 1-aminobutadiynes with anilines was described. By tuning the steric and electronic properties of anilines, 2-aminoquinoline scaffold was constructed instead of the literature-reported 2-amidopyrroles. Notedly, the reactions of polyaromatic amines also proceed smoothly to afford nitrogen-containing polyaromatics. (Figure presented.).
- Liu, Ningning,Sun, Huaming,Wang, Junying,Zhang, Zunting,Wang, Tao
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supporting information
p. 5443 - 5447
(2021/10/12)
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- Nitrene Photochemistry of Manganese N-Haloamides**
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Manganese complexes supported by macrocyclic tetrapyrrole ligands represent an important platform for nitrene transfer catalysis and have been applied to both C?H amination and olefin aziridination catalysis. The reactivity of the transient high-valent Mn nitrenoids that mediate these processes renders characterization of these species challenging. Here we report the synthesis and nitrene transfer photochemistry of a family of MnIII N-haloamide complexes. The S=2 N-haloamide complexes are characterized by 1H NMR, UV-vis, IR, high-frequency and -field EPR (HFEPR) spectroscopies, and single-crystal X-ray diffraction. Photolysis of these complexes results in the formal transfer of a nitrene equivalent to both C?H bonds, such as the α-C?H bonds of tetrahydrofuran, and olefinic substrates, such as styrene, to afford aminated and aziridinated products, respectively. Low-temperature spectroscopy and analysis of kinetic isotope effects for C?H amination indicate halogen-dependent photoreactivity: Photolysis of N-chloroamides proceeds via initial cleavage of the Mn?N bond to generate MnII and amidyl radical intermediates; in contrast, photolysis of N-iodoamides proceeds via N?I cleavage to generate a MnIV nitrenoid (i.e., {MnNR}7 species). These results establish N-haloamide ligands as viable precursors in the photosynthesis of metal nitrenes and highlight the power of ligand design to provide access to reactive intermediates in group-transfer catalysis.
- Bhuvanesh, Nattamai,Das, Anuvab,Figgins, Matthew T.,Hicks, Madeline H.,Ozarowski, Andrew,Powers, David C.,Reid, Kaleb A.,Telser, Joshua,Van Trieste, Gerard P.
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supporting information
p. 26647 - 26655
(2021/11/18)
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- Nickel/Photoredox Dual Catalytic Cross-Coupling of Alkyl and Amidyl Radicals to Construct C(sp3)-N Bonds
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The construction of C(sp3)-N bonds via direct radical-radical cross-coupling under benign conditions is a desirable but challenging approach. Herein, the cross-coupling of alkyl and amidyl radicals to build aliphatic C-N bonds in a concise, mild, and oxid
- Zhou, Shaofang,Lv, Kang,Fu, Rui,Zhu, Changlei,Bao, Xiaoguang
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p. 5026 - 5034
(2021/05/07)
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- Metal-free hydroalkoxylation of ynesulfonamides with esters
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An efficient metal-free hydroalkoxylation reaction of ynesulfonamides with esters under mild conditions is described. Under the catalysis of TMSOTf, various ynesulfonamides are transformed into the corresponding alkoxy-substituted enamides in high yields
- Gao, Erhui,Peng, Cheng,Zhang, Jingyi,Wang, Xiao-Na,Chang, Junbiao
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supporting information
p. 2182 - 2185
(2021/03/26)
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- Facile synthesis of sulfonyl chlorides/bromides from sulfonyl hydrazides
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A simple and rapid method for efficient synthesis of sulfonyl chlorides/bromides from sulfonyl hydrazide with NXS (X = Cl or Br) and late-stage conversion to several other functional groups was described. A variety of nucleophiles could be engaged in this transformation, thus permitting the synthesis of complex sulfonamides and sulfonates. In most cases, these reactions are highly selective, simple, and clean, affording products at excellent yields.
- Chen, Rongxiang,Xu, Shaohong,Shen, Fumin,Xu, Canran,Wang, Kaikai,Wang, Zhanyong,Liu, Lantao
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- Copper-boryl mediated transfer hydrogenation of N-sulfonyl imines using methanol as the hydrogen donor
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B2Pin2-assisted copper-catalyzed transfer hydrogenation of aromatic sulfonylimines has been achieved, delivering a variety of aryl/heteroaryl sulfonamides in good to excellent yields under mild reaction conditions and with methanol a
- He, Yi,Li, Shi-Guang,Mbaezue, Ifenna I.,Reddy, Angula C.S.,Tsantrizos, Youla S.
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supporting information
(2021/03/24)
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- Diiodine-Triethylsilane System: Reduction of N-Sulfonyl Aldimines to N-Alkylsulfonamides
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Because molecular iodine and hydrosilanes are stable to both air and moisture, reactions using these reagents are easy to operate and require mild reaction conditions. Molecular iodine and a hydrosilane were used to reduce N-sulfonyl aldimines to the corr
- Jiang, Jin,Xiao, Lili,Li, Yu-Long
-
supporting information
p. 291 - 294
(2020/11/09)
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- Method for synthesizing N-alkyl sulfonamide in water
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The invention discloses a method for synthesizing N-alkyl sulfonamide in water, in particular to a method for synthesizing an N-alkyl sulfonamide derivative from a sulfonamide derivative and alcohol,and a water-soluble iridium complex is adopted to catalyze the reaction of N-alkyl sulfonamide. Compared with the previous synthesis method, the method has the advantages that a reaction equivalent substrate is used in the reaction process, so that raw material waste is avoided; weak base is used, and reaction conditions are mild; non-toxic and harmless pure water is used as a solvent in the reaction, only water is generated as a by-product, the atom reaction economy is high, and the requirement of green chemistry is met.
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Paragraph 0023; 0024; 0025; 0026; 0027
(2020/12/30)
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- Visible-Light-Mediated N-Desulfonylation of N-Heterocycles Using a Heteroleptic Copper(I) Complex as a Photocatalyst
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A photoredox protocol that uses a heteroleptic Cu (I) complex, [Cu(dq)(BINAP)]BF4, has been developed for the photodeprotection of benzenesulfonyl-protected N-heterocycles. A range of substrates was examined, including indazoles, indoles, pyrazoles, and benzimidazole, featuring both electron-rich and electron-deficient substituents, giving good yields of the N-heterocycle products with broad functional group tolerance. This transformation was also found to be amenable to flow reaction conditions.
- Hunter, Cameron J.,Boyd, Michael J.,May, Gregory D.,Fimognari, Robert
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p. 8732 - 8739
(2020/07/16)
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- Straightforward synthesis, spectroscopic characterizations and comprehensive DFT calculations of novel 1-ester 4-sulfonamide-1,2,3-triazole scaffolds
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For the first time, an efficient click azide?alkyne [3 + 2] cycloaddition reaction for synthesis of new 1-ester 4-sulfonamide-1,2,3-triazole derivatives was developed via a three-component reaction of N-propargylsulfonamides, sodium azide, and α-haloesters in a one pot method. The mild reaction conditions, avoiding the isolation of hazardous organic azides, good yields (65–78%), and commercially available and inexpensive starting materials are advantages of this cycloaddition reaction for synthesis of fine chemicals. The all desired products were characterized by FT-IR, 1H and 13C NMR spectroscopy. The HOMO-LUMO analysis (electrophilicity index), vibrational frequencies (FT-IR), 1H and 13C chemical shift values and Li+ and Na+ ion affinities of a desired product have been also calculated by density functional theory (DFT). Lithium ion affinity of the product was determined as 80.78 kJ/mol higher than its sodium ion affinity. The NICS index was used to confirm of the cation π interaction in complex of the synthesized product with Li+ and Na+ ions.
- Alizadeh, Maryam,Mirjafary, Zohreh,Saeidian, Hamid
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- Electrochemical Vicinal Difluorination of Alkenes: Scalable and Amenable to Electron-Rich Substrates
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Fluorinated alkyl groups are important motifs in bioactive compounds, positively influencing pharmacokinetics, potency and conformation. The oxidative difluorination of alkenes represents an important strategy for their preparation, yet current methods are limited in their alkene-types and tolerance of electron-rich, readily oxidized functionalities, as well as in their safety and scalability. Herein, we report a method for the difluorination of a number of unactivated alkene-types that is tolerant of electron-rich functionality, giving products that are otherwise unattainable. Key to success is the electrochemical generation of a hypervalent iodine mediator using an “ex-cell” approach, which avoids oxidative substrate decomposition. The more sustainable conditions give good to excellent yields in up to decagram scales.
- Doobary, Sayad,Sedikides, Alexi T.,Caldora, Henry P.,Poole, Darren L.,Lennox, Alastair J. J.
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supporting information
p. 1155 - 1160
(2019/12/11)
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- Electron Transfer Photoredox Catalysis: Development of a Photoactivated Reductive Desulfonylation of an Aza-Heteroaromatic Ring
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Herein, we report a protocol for desulfonylation of aza-heteroaromatic rings via photoinduced electron transfer and hydrogen atom transfer. This general protocol has a wide substrate range and moderate to good yields. The utility of the method was demonstrated by the chemoselective desulfonylation of a molecule containing both an aliphatic and an aromatic sulfonamide. (Figure presented.).
- Qiang-Liu,Liu, Yu-Xiu,Song, Hong-Jian,Wang, Qing-Min
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supporting information
p. 3110 - 3115
(2020/07/04)
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- Electrochemical synthesis of sulfonamides in a graphite powder macroelectrode
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The electrochemical generation of sulfinyl radicals from commercially available and non-expensive sodium salts of sulfinic acids is described. Electrooxidation reactions were carried out in a graphite powder macroelectrode using an aqueous electrolyte and cavity cell. Further reaction with primary or secondary amines gave the corresponding sulfonamides, a unit present in several biologically active compounds and pharmaceuticals, in good yields.
- Galdino, Danilo,Menezes, Paulo H.,Navarro, Marcelo,Vicente, Dmistocles A.
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p. 5262 - 5266
(2020/09/17)
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- Preparation method of nitrogen-substituted sulfonamide compound
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The invention discloses a preparation method of a nitrogen-substituted sulfonamide compound, and belongs to the field of organic synthesis. The nitrogen-substituted sulfonamide compound as shown in aformula (I) is prepared by directly coupling an aryl sulfonamide compound as shown in a formula (II) and a p-toluenesulfonylhydrazone compound as shown in a formula (III) under the action of a specific copper catalyst, an alkali reagent and an additive without ligand participation and a high-temperature reaction system. According to the method, the raw materials are cheap and easy to obtain, the reaction process is green, simple and convenient, and the yield of the nitrogen-substituted sulfonamide compound can reach 76%.
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Paragraph 0031-0034; 0046-0047; 0051
(2020/04/02)
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- Metal-free C-H Activation over Graphene Oxide toward Direct Syntheses of Structurally Different Amines and Amides in Water
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Unprecedented metal-free synthesis of a variety of amines and amides is reported via amination of C(sp3)-H and C(sp2)-H bonds. The strategy involves graphene-oxide/I2-catalyzed nitrene insertion using PhINTs as a nitrene (NT) source in water at room temperature. A wide range of structurally different substrates, viz., cyclohexane, cyclic ethers, arenes, alkyl aromatic systems, and aldehydes/ketones, having an α-phenyl ring have been employed successfully to afford the corresponding nitrene insertion product in good yield, albeit low in few cases. The envisaged method has superiority over others in terms of its operational simplicity, metal-free catalysis, use of water as a solvent, ambient reaction conditions, and reusability of the catalyst.
- Shukla, Prashant,Asati, Ambika,Bhardiya, Smita R.,Singh, Manorama,Rai, Vijai K.,Rai, Ankita
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p. 15552 - 15561
(2020/12/02)
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- C(sp3)-H Bond Arylation and Amidation of Si-Bound Methyl Group via Directing Group Strategy
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Silylmethyl functionalization provides a general and efficient access to diverse organosilanes. The traditional methods for silylmethyl functionalization often involved silylmethylmetals or silylmethylhalides. In recent years, a C-H activation strategy has become one of the most attractive alternatives in organic synthesis. We envisioned that the attachment of a coordinating group at silicon of methylsilanes provides the opportunity to modify the silylmethyl group via directed C-H bond functionalization. However, despite employment of silicon tethers bearing a directing group (DG) for C(sp2)-H functionalization has been well established due to the fact that the silicon tethers are easily installable and removable/modifiable, applying this concept toward C(sp3)-H functionalization remains underdeveloped. Herein, we successfully develop IrIII/RhIII-catalyzed C-H bond arylation/amidation of silyl methyl group by using directing group strategy, which constitutes the most powerful access to benzylsilanes and amino-substituted silanes. Moreover, we demonstrated that the pyridine directing group on silicon atom can be easily removed, and the starting materials can also be efficiently recovered, which are different from those of pyridine-directed C-H functionalization of C-bound methyl group.
- Han, Jie-Lian,Qin, Ying,Zhao, Dongbing
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p. 6020 - 6026
(2019/06/25)
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- The: N -alkylation of sulfonamides with alcohols in water catalyzed by a water-soluble metal-ligand bifunctional iridium complex [Cp?Ir(biimH2)(H2O)][OTf]2
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The iridium complex [Cp?Ir(biimH2)(H2O)][OTf]2 (Cp? = η5-pentamethylcyclopentadienyl, biimH2 = 2,2′-biimidazole) was synthesized and developed as a new-type of water-soluble metal-ligand bifunctional catalyst for the N-alkylation of poorly nucleophilic sulfonamides with alcohols in water. In the presence of catalyst (1 mol%) and Cs2CO3 (0.1 equiv.), a series of desirable products was obtained in 74-91% yields under microwave irradiation. Mechanistic experiments revealed that the presence of NH units in the imidazole ligand is crucially important for the catalytic activity of the iridium complex. Notably, this research would facilitate the process of water-soluble metal-ligand bifunctional catalysis for the hydrogen autotransfer process.
- Ai, Yao,Liu, Pengcheng,Liang, Ran,Liu, Yan,Li, Feng
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p. 10755 - 10762
(2019/07/15)
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- A bifunctional strategy for N-heterocyclic carbene-stabilized iridium complex-catalyzed: N -alkylation of amines with alcohols in aqueous media
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Through the strategy of combining bifunctional 2-hydroxypyridine and a thermally stable N-heterocyclic carbene ligand, an Ir-catalyzed N-monoalkylation reaction has been developed in aqueous media under base-free conditions. This reaction proceeds smoothly with high yields of various aromatic amines and sulfonamides with a wide range of primary alcohols. Experimental and computational studies revealed a metal-ligand cooperative mechanism and its thermal stability during the bifunctional catalysis in aqueous media.
- Huang, Ming,Li, Yinwu,Liu, Jiahao,Lan, Xiao-Bing,Liu, Yan,Zhao, Cunyuan,Ke, Zhuofeng
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supporting information
p. 219 - 224
(2019/01/28)
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- Manganese-Catalyzed N-Alkylation of Sulfonamides Using Alcohols
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An efficient manganese-catalyzed N-alkylation of sulfonamides has been developed. This borrowing hydrogen approach employs a well-defined and bench-stable Mn(I) PNP pincer precatalyst, allowing benzylic and simple primary aliphatic alcohols to be employed as alkylating agents. A diverse range of aryl and alkyl sulfonamides undergoes mono-N-alkylation in excellent isolated yields (32 examples, 85% average yield).
- Reed-Berendt, Benjamin G.,Morrill, Louis C.
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p. 3715 - 3724
(2019/03/30)
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- Solvent-Free N-Alkylation of Amides with Alcohols Catalyzed by Nickel on Silica–Alumina
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The N-alkylation of phenylacetamide with benzyl alcohol has been studied using Ni/SiO2–Al2O3. In the optimized conditions, the desired product was isolated in an excellent 98 % yield. The reaction could advantageously be performed in neat conditions, with a slight excess of amide and a catalytic amount of base. These conditions were tested on a large range of amides and alcohols, affording 24 compounds in 13 to 99 % isolated yields.
- Charvieux, Aubin,Le Moigne, Louis,Borrego, Lorenzo G.,Duguet, Nicolas,Métay, Estelle
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supporting information
p. 6842 - 6846
(2019/11/11)
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- Reductions of Imines Using Zirconocene Chloride Hydride
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Herein, we describe the fast, chemoselective, and clean reduction of imines with zirconocene chloride hydride. The reaction works well on aromatic and enolizable aliphatic aldimines, as well as ketimines. A range of N-protecting groups and various functio
- Vargová, Denisa,Mudráková, Brigita,Némethová, Ivana,?ebesta, Radovan
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p. 7606 - 7612
(2019/12/03)
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- Dihydridoboranes: Selective Reagents for Hydroboration and Hydrodefluorination
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The preparation of a new series of dihydridoboranes supported by N,N-chelating ligands, [R2NCH2CH2NAr]- (R = alkyl, Ar = aryl), is reported. These new boranes react selectively with carbonyls, imines, and a series of electron-deficient fluoroarenes. The reactivity is complementary to recognized reagents such as pinacolborane, catecholborane, NHC-BH3, and borane (BH3) itself. Selectivities are rationalized by invoking both open- A nd closed-chain forms of the reagents as part of equilibrium mixtures.
- Phillips, Nicholas A.,O'hanlon, James,Hooper, Thomas N.,White, Andrew J. P.,Crimmin, Mark R.
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supporting information
p. 7289 - 7293
(2019/10/08)
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- Borinic Acid Mediated Hydrosilylations: Reductions of Carbonyl Derivatives
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4-Fluoro-2-chlorophenylborinic acid acts as a precatalyst in the presence of phenylsilane for the facile reduction of ketones, aldehydes and imines. Notably, synergistic mediation of a tertiary amine was found essential to trigger silicon to boron hydride transfer to generate a key amine–diarylhydroborane Lewis complex.
- Chardon, Aurélien,Rouden, Jacques,Blanchet, Jér?me
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supporting information
p. 995 - 998
(2018/12/13)
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- Unified Approach to the Chemoselective α-Functionalization of Amides with Heteroatom Nucleophiles
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Functionalization at the α-position of carbonyl compounds has classically relied on enolate chemistry. As a result, the generation of a new C-X bond, where X is more electronegative than carbon requires an oxidation event. Herein we show that, by rendering the α-position of amides electrophilic through a mild and chemoselective umpolung transformation, a broad range of widely available oxygen, nitrogen, sulfur, and halogen nucleophiles can be used to generate α-functionalized amides. More than 60 examples are presented to establish the generality of this process, and calculations of the mechanistic aspects underline a fragmentation pathway that accounts for the broadness of this methodology.
- Gon?alves, Carlos R.,Lemmerer, Miran,Teskey, Christopher J.,Adler, Pauline,Kaiser, Daniel,Maryasin, Boris,González, Leticia,Maulide, Nuno
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supporting information
p. 18437 - 18443
(2019/11/21)
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- Metal-free synthesis of activated ynesulfonamides and tertiary enesulfonamides
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An operationally simple synthesis of activated ynesulfonamides and enesulfonamides is described. Ynesulfonamides can be obtained through reaction of sulfonylamides with activated bromoalkynes and Triton B in a short time at room temperature. Likewise, terminal alkynes react with sulfonylamides to provide enesulfonamides. Z/E enesulfonamides can be transformed exclusively into E enesulfonamides.
- Andna, Lucile,Miesch, Laurence
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supporting information
p. 5688 - 5692
(2019/06/19)
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- A Micellar Catalysis Strategy for Amidation of Alkynyl Bromides: Synthesis of Ynamides in Water
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Copper-catalyzed amidation of alkynyl bromides can be carried out in water for the first time, which is made possible by a micellar catalysis strategy using rosin-based surfactant APGS-550-M. The surfactant can be easily prepared from natural abundant biomass, resin acids. Studies as to substrate scope and reaction aqueous medium recycling showcase the ease and sustainability of this technology.
- Yang, Yunqin,Meng, Xiangtai,Zhu, Baolong,Jia, Ying,Cao, Xiaoji,Huang, Shenlin
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supporting information
p. 1166 - 1169
(2019/01/04)
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- Transition-Metal-Free One-Step Synthesis of Ynamides
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A robust transition-metal-free one-step strategy for the synthesis of ynamides from sulfonamides and (Z)-1,2-dichloroalkenes or alkynyl chlorides is presented. This method is not only effective for internal ynamides but also amenable for terminal ynamides. Various functional groups, even the vinyl moiety, are compatible, and thus, this strategy offers the opportunity for further functionalization.
- Zeng, Xianzhu,Tu, Yongliang,Zhang, Zhenming,You, Changming,Wu, Jiao,Ye, Zhiying,Zhao, Junfeng
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p. 4458 - 4466
(2019/03/26)
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- Efficient synthesis, spectroscopic characterization and DFT based studies of novel 1-amide 4-sulfonamide-1,2,3-triazole derivatives
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In the present study, for the first time 1-amide 4-sulfonamide-1,2,3-triazole scaffolds were synthesized by using an azide-alkyne Huisgen cycloaddition reaction. The target products were obtained in moderate to good yields (45–75%) by using catalytic CuI and green system H2O/EtOH. The easy availability of the inexpensive starting materials, avoiding isolation and handling of hazardous organic azides and mild reaction conditions make this method a valuable tool for generating functionalized 1,2,3-triazole derivatives. The unambiguous characterization of synthesized compounds was accomplished by using various spectroscopic techniques such as 1H NMR, 13C NMR, and FT-IR. The information regarding optimized geometry, were obtained by applying DFT/B3LYP-6-31G(d) method. The electrophilicity index, 1H and 13C chemical shift values, lithium and sodium ion affinities of the desired product 3b have been also calculated by the mentioned method. As a whole, the calculated results were found in close agreement to that of experimental data. The studies revealed that the compound 3b possesses good Li+ and Na+ affinity and cation π interaction plays a vital role in the complexation of 3b. For the first time, nucleus–independent chemical shift index was used to confirm the cation π interaction of 3b.
- Bonyad, Sarvenaz Rouhi,Mirjafary, Zohreh,Saeidian, Hamid,Rouhani, Morteza
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p. 164 - 170
(2019/07/18)
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- Designed To React: Terminal Copper Nitrenes and Their Application in Catalytic C?H Aminations
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Heteroscorpionate ligands of the bis(pyrazolyl)methane family have been applied in the stabilisation of terminal copper tosyl nitrenes. These species are highly active intermediates in the copper-catalysed direct C?H amination and nitrene transfer. Novel perfluoroalkyl-pyrazolyl- and pyridinyl-containing ligands were synthesized to coordinate to a reactive copper nitrene centre. Four distinct copper tosyl nitrenes were prepared at low temperatures by the reaction with SO2tBuPhINTs and copper(I) acetonitrile complexes. Their stoichiometric reactivity has been elucidated regarding the imination of phosphines and the aziridination of styrenes. The formation and thermal decay of the copper nitrenes were investigated by UV/Vis spectroscopy of the highly coloured species. Additionally, the compounds were studied by cryo-UHR-ESI mass spectrometry and DFT calculations. In addition, a mild catalytic procedure has been developed where the copper nitrene precursors enable the C?H amination of cyclohexane and toluene and the aziridination of styrenes.
- Moegling, Julian,Hoffmann, Alexander,Thomas, Fabian,Orth, Nicole,Liebh?user, Patricia,Herber, Ulrich,Rampmaier, Robert,Stanek, Julia,Fink, Gerhard,Ivanovi?-Burmazovi?, Ivana,Herres-Pawlis, Sonja
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supporting information
p. 9154 - 9159
(2018/07/25)
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- Iridium(III)- benzoxazolyl and benzothiazolyl phosphine ligands catalyzed versatile alkylation reactions with alcohols and the synthesis of quinolines and indole
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A series of benzoxazolyl and benzothiazolyl phosphine ligands 4a-4g were synthesized and characterized, which prepared from commercially available 2-aminophenol/2-aminobenzenethiol and 2-bromobenzaldehyde via cyclization and phosphination. The representative ligands 4c and 4e were determined by single-crystal X-ray diffraction. The corresponding iridium complexes could be generated in situ when [Cp*IrCl2]2 (Cp* = pentamethylcyclopentadienyl) encountered ligands. The molecular structures of complexes 5c and 5e were crystallographically characterized. The dihedral angles of N (1)-C (1)-C (8)-C (9) showed an increasing twist compared with the corresponding ligand. The iridium (III) catalysts were screened, [Cp*IrCl2]2/4a proved to be the optimal catalyst, which exhibited efficient catalytic activity toward versatile alkylations including ketones, secondary alcohols and amines with primary alcohols. Additionally, the synthesis of quinolines from ketones with 2-aminobenzyl alcohol by intermolecular cyclization and indole from 2-(2-aminophenyl)ethanol by intramolecular cyclization were achieved under the optimized conditions.
- Huang, Shuang,Wu, Si-Peng,Zhou, Quan,Cui, He-Zhen,Hong, Xi,Lin, Yue-Jian,Hou, Xiu-Feng
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- Method for catalytic synthesis of N-benzyl benzene sulfonamide compounds by boric acid/oxalic acid catalytic system under microwave radiation
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The invention discloses a method for catalytic synthesis of N-benzyl benzene sulfonamide compounds by a boric acid/oxalic acid catalytic system under microwave radiation. The method includes: adoptingbenzyl alcohol and derivatives thereof and benzene sulfonamide derivatives as raw materials, adopting the boric acid/oxalic acid system as a catalyst, and adopting fluorobenzene as a solvent; performing reaction in a microwave reactor under certain temperature and power conditions, performing vacuum concentration after reaction for a period of time, and subjecting a product to column chromatographic purification to realize efficient catalytic preparation of the N-benzyl benzene sulfonamide compounds. Compared with the prior art, the method has advantages of evidently higher reaction speed than that of conventional heating, mild reaction conditions, simplicity in operation, high yield, safety, low cost and environmental friendliness.
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Paragraph 0031; 0071
(2018/09/11)
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