- Catalytic C-N Bond-Forming Reactions Enabled by Proton-Coupled Electron Transfer Activation of Amide N-H Bonds
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Over the past three years, our group has become interested in the ability of proton-coupled electron transfer (PCET) to facilitate direct homolytic bond activations of common organic functional groups that are challenging substrates for conventional hydro
- Nguyen, Lucas Q.,Knowles, Robert R.
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- Extended Hydrogen Bond Networks for Effective Proton-Coupled Electron Transfer (PCET) Reactions: The Unexpected Role of Thiophenol and Its Acidic Channel in Photocatalytic Hydroamidations
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Preorganization and aggregation in photoredox catalysis can significantly affect reactivities or selectivities but are often neglected in synthetic and mechanistic studies, since the averaging effect of flexible ensembles can effectively hide the key activation signatures. In addition, aggregation effects are often overlooked due to highly diluted samples used in many UV studies. One prominent example is Knowles's acceleration effect of thiophenol in proton-coupled electron transfer mediated hydroamidations, for which mainly radical properties were discussed. Here, cooperative reactivity enhancements of thiophenol/disulfide mixtures reveal the importance of H-bond networks. For the first time an in-depth NMR spectroscopic aggregation and H-bond analysis of donor and acceptor combined with MD simulations was performed revealing that thiophenol acts also as an acid. The formed phosphate-H+-phosphate dimers provide an extended H-bond network with amides allowing a productive regeneration of the photocatalyst to become effective. The radical and acidic properties of PhSH were substituted by Ph2S2 and phosphoric acid. This provides a handle for optimization of radical and ionic channels and yields accelerations up to 1 order of magnitude under synthetic conditions. Reaction profiles with different light intensities unveil photogenerated amidyl radical reservoirs lasting over minutes, substantiating the positive effect of the H-bond network prior to radical cyclization. We expect the presented concepts of effective activation via H-bond networks and the reactivity improvement via the separation of ionic and radical channels to be generally applicable in photoredox catalysis. In addition, this study shows that control of aggregates and ensembles will be a key to future photocatalysis.
- Berg, Nele,Bergwinkl, Sebastian,Nuernberger, Patrick,Horinek, Dominik,Gschwind, Ruth M.
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supporting information
p. 724 - 735
(2021/02/01)
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- Flow synthesis of N-alkyl-5-methyl-2-pyrrolidones over Ni2P/SiO2 catalyst
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N-alkyl-5-methyl-2-pyrrolidones are an attractive alternative to the common solvent N-methyl-2-pyrrolidone (NMP) and can be used as starting materials for synthesis of various valuable chemicals. Reductive amination of alkyl levulinates derived from biomass feedstock is a promising method for production of these compounds. In the present work, N-alkyl-5-methyl-2-pyrrolidones were obtained in excellent yields by reductive amination of ethyl levulinate with alkylamines over SiO2-supported nickel phosphide in a flow reactor using molecular hydrogen as a reducing agent. At the same time, aromatic amines and 1-nitropropane give a lower yield of the corresponding pyrrolidones. The influence of the solvent nature, temperature, pressure, hydrogen and liquid flow rates on the catalyst performance was studied.
- Bukhtiyarova, Galina A.,Nuzhdin, Alexey L.,Shamanaev, Ivan V.,Wang, Yazhou
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- One-pot synthesis of pyrrolidones from levulinic acid and amines/nitroarenes/nitriles over the Ir-PVP catalyst
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The synthesis of pyrrolidones via reductive amination of levulinic acid with aniline was examined over polypyrrolidone-stabilized metal nanoparticle catalysts. Among them, Ir metal was the most effective and applicable for the reductive amination of levulinic acid with nitroarenes/nitriles. Importantly, this catalyst was used for the one-pot synthesis of the anti-inflammatory drug indoprofen from 2-formylbenzoic acid and 2-(4-nitrophenyl)propanoic acid.
- Chaudhari, Chandan,Nagaoka, Katsutoshi,Nishida, Yoshihide,Sato, Katsutoshi,Shiraishi, Masaya
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supporting information
p. 7760 - 7764
(2020/11/27)
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- Reductive amination of levulinic acid to N-substituted pyrrolidones over RuCl3 metal ion anchored in ionic liquid immobilized on graphene oxide
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Reductive amination of biomass derived Levulinic acid (LA) for the synthesis of N-substituted pyrrolidones is one of the highly attractive routes for biomass valorization. The supported homogeneous metal precursor into the solid surface is an important context in the field of catalysis because these types of catalysts provide the heterogeneous nature and meet the needs of recyclability. Herein, we have reported a synthesis of catalyst with ruthenium ion supported on ionic liquid immobilized into graphene oxide (Ru?GOIL) and its application for reductive amination reaction. Synthesized catalyst is characterized using different analytical techniques such as FT-IR, XRD, XPS, TGA, FEG-SEM, TEM and EXAFS analysis. The prepared Ru?GOIL found to be highly effective for reductive amination of LA and under these optimized conditions various N-substituted pyrrolidones derivatives were synthesized in excellent yield (78–93%). Ru?GOIL catalyst demonstrated great catalytic performance for reductive amination reaction of LA giving good turnover frequency (TOF = 62 h?1) value in comparison with other catalysts. The Ru?GOIL catalyst was recycled for six reaction runs with slight drop-in activity after 4th cycle. Practical applicability of the developed catalyst was successfully demonstrated by direct transformation of biomass waste (rice husk and wheat straw) derived LA to N-substituted pyrrolidones.
- Raut, Amol B.,Shende, Vaishali S.,Sasaki, Takehiko,Bhanage, Bhalchandra M.
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p. 206 - 214
(2020/02/15)
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- Investigation towards the reductive amination of levulinic acid by B(C6F5)3/hydrosilane system
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The selective transformation of the renewable biomass resources into the highly value-added platform chemicals is essentially important for sustainable chemistry. Here we report a simple and highly efficient strategy for the synthesis of N-heterocyclic co
- He, Jianghua,Wang, Tianlong,Xu, Hai,Zhang, Yuetao
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- Ambient reductive synthesis of N-heterocyclic compounds over cellulose-derived carbon supported Pt nanocatalyst under H2atmosphere
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N-heterocyclic compounds are important chemicals, and their reductive synthesis using H2 under mild conditions is attractive but challenging. Herein, we report chemoselective hydrogenation of 2-nitroacylbenzenes to 2,1-benzisoxazoles under ambient conditions for the first time, wihch is achieved over cellulose-derived carbon (c-C) supported Pt nanocatalyst (Pt/c-C), and a series of 2,1-benzisoxazoles can be obtained in excellent yields. Pt/c-C also shows high performance for ambient reductive amination of levulinic acid with H2, accessing various pyrrolidones in excellent yields. The systematic studies indicated that the c-C support played multiple roles in catalysis with enhancing electron density of the Pt nanoparticles and activating reactant molecules. Especially, the O-containing groups on the c-C surface provided the c-C support with both acid and base features, thus endowing Pt/c-C with high performances. This work provides an accessible and highly efficient catalyst for reductive synthesis of N-heterocycles using H2 under ambient conditions, which may have promising applications.
- Wu, Yunyan,Wu, Yunyan,Zhao, Yanfei,Zhao, Yanfei,Wang, Huan,Wang, Huan,Zhang, Fengtao,Zhang, Fengtao,Li, Ruipeng,Li, Ruipeng,Xiang, Junfeng,Wang, Zhenpeng,Han, Buxing,Liu, Zhimin
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p. 3820 - 3826
(2020/07/06)
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- A Facile Direct Route to N-(Un)substituted Lactams by Cycloamination of Oxocarboxylic Acids without External Hydrogen
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Lactams are privileged in bioactive natural products and pharmaceutical agents and widely featured in functional materials. This study presents a novel versatile approach to the direct synthesis of lactams from oxocarboxylic acids without catalyst or external hydrogen. The method involves the in situ release of formic acid from formamides induced by water to facilitate efficient cycloamination. Water also suppresses the formation of byproducts. This unconventional pathway is elucidated by a combination of model experiments and density functional theory calculations, whereby cyclic imines (5-methyl-3,4-dihydro-2-pyrrolone and its tautomeric structures) are found to be favorable intermediates toward lactam formation, in contrast to the conventional approach encompassing cascade reductive amination and cyclization. This sustainable and simple protocol is broadly applicable for the efficient production of various N-unsubstituted and N-substituted lactams.
- Li, Hu,Wu, Hongguo,Zhang, Heng,Su, Yaqiong,Yang, Song,Hensen, Emiel J. M.
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p. 3778 - 3784
(2019/08/07)
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- Reductive amination of ethyl levulinate to pyrrolidones over AuPd nanoparticles at ambient hydrogen pressure
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Herein, we describe a AuPd catalyst for selective and solventless conversion of ethyl levulinate (EL) and amines to pyrrolidones under ambient pressure. The optimized Au66Pd34 nanoparticle catalyst was stable and reusable over 10 runs. AuPd catalysis was extended to reductive amination of levulinic acid and 4-acetylbutyric acid, providing a green chemistry approach under milder conditions not only to pyrrolidones, but also to piperidines, both of which are important scaffolds in designing polymers, natural products and pharmaceuticals.
- Muzzio, Michelle,Yu, Chao,Lin, Honghong,Yom, Typher,Boga, Dilek A.,Xi, Zheng,Li, Na,Yin, Zhouyang,Li, Junrui,Dunn, Joshua A.,Sun, Shouheng
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supporting information
p. 1895 - 1899
(2019/04/29)
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- Iron-Catalysed Switchable Synthesis of Pyrrolidines vs Pyrrolidinones by Reductive Amination of Levulinic Acid Derivatives via Hydrosilylation
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A selective production of pyrrolidines vs pyrrolidinones via hydrosilylation of levulinic acid and levulinates by switching of the iron complex catalyst is presented herein. The reactions proceeded efficiently with various anilines and alkylamines under both visible light irradiation and thermal conditions with 43 examples in isolated yields up to 93%. Noticeably, under similar conditions, cyclic amines such as piperidines and azepanes were efficiently synthesized with yields up to 92%, by reaction of anilines with 1,5- or 1,6-keto acids, respectively. Similarly, N-arylinsolidoline compounds can be prepared from 2-formylbenzoic acid in 57–93% yields. (Figure presented.).
- Wei, Duo,Netkaew, Chakkrit,Darcel, Christophe
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supporting information
p. 1781 - 1786
(2019/02/26)
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- Ambient Reductive Amination of Levulinic Acid to Pyrrolidones over Pt Nanocatalysts on Porous TiO2 Nanosheets
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Construction of N-substituted pyrrolidones from biomass-derived levulinic acid (LA) via reductive amination is a highly attractive route for biomass valorization. However, realizing this transformation using H2 as the hydrogen source under mild conditions is still very challenging. Herein, we designed porous TiO2 nanosheets-supported Pt nanoparticles (Pt/P-TiO2) as the heterogeneous catalyst. The prepared Pt/P-TiO2 was highly efficient for reductive amination of LA to produce various N-substituted pyrrolidones (34 examples) at ambient temperature and H2 pressure. Meanwhile, Pt/P-TiO2 showed good applicability for reductive amination of levulinic esters, 4-acetylbutyric acid, 2-acetylbenzoic acid, and 2-carboxybenzaldehyde. Systematic studies indicated that the strong acidity of P-TiO2 and the lower electron density of the Pt sites as well as the porous structure resulted in the excellent activity of Pt/P-TiO2.
- Xie, Chao,Song, Jinliang,Wu, Haoran,Hu, Yue,Liu, Huizhen,Zhang, Zhanrong,Zhang, Pei,Chen, Bingfeng,Han, Buxing
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p. 4002 - 4009
(2019/03/07)
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- Formic acid as a hydrogen source for the iridium-catalyzed reductive amination of levulinic acid and 2-formylbenzoic acid
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The aqueous phase catalytic reductive amination of levulinic acid (LA) into pyrrolidones and 2-formylbenzoic acid into N-arylisoindolines is reported. The catalytic reaction involves an iridium catalyst bearing an electron-rich dipyridylamine ligand and u
- Wang, Shengdong,Huang, Haiyun,Bruneau, Christian,Fischmeister, Cédric
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p. 4077 - 4082
(2019/08/07)
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- Noble metal-free upgrading of multi-unsaturated biomass derivatives at room temperature: Silyl species enable reactivity
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Biomass derivatives are a class of oxygen-rich organic compounds, which can be selectively upgraded to various value-added molecules by partial or complete hydrogenation over metal catalysts. Here, we show that Cs2CO3, a low-cost commercial chemical, enables the selective reduction of dicarbonyl compounds including bio-derived carboxides to monohydric esters/amides, hydroxylamines or diols with high yields (82-99%) at room temperature using eco-friendly and equivalent hydrosilane as a hydride donor. The in situ formation of silyl ether enables the developed catalytic system to tolerate other unsaturated groups and permits a wide substrate scope with high selectivities. Spectroscopic and computational studies elucidate reaction pathways with an emphasis on the role of endogenous siloxane.
- Li, Hu,Zhao, Wenfeng,Dai, Wenshuai,Long, Jingxuan,Watanabe, Masaru,Meier, Sebastian,Saravanamurugan, Shunmugavel,Yang, Song,Riisager, Anders
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p. 5327 - 5335
(2018/12/05)
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- A process for preparing a cyclic lactam derivative method (by machine translation)
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The present invention provides a process for preparing a cyclic lactam derivatives, organic chemical technical field. The invention relates to acid or ester as the raw material, to synthesize a cyclic lactam derivative, in particular in accordance with th
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Paragraph 0047; 0048; 0052; 0054; 0056; 0060
(2018/07/06)
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- Raney-Ni catalyzed conversion of levulinic acid to 5-methyl-2-pyrrolidone using ammonium formate as the H and N source
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Renewable biomass based levulinic acid was converted to 5-methyl-2-pyrrolidone in 94% yield by a Raney-Ni catalyzed process using ammonium formate in aqueous medium and heating at 180 °C for 3 h. The Raney-Ni could be reused for four catalytic cycles with about 10% loss in catalytic activity. In a similar reaction levulinic acid could be converted 1-substituted-5-methyl-2-pyrrolidones in 90–95% yield by using a mixture of formic acid and the corresponding primary amine.
- Amarasekara, Ananda S.,Lawrence, Yen Maroney
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supporting information
p. 1832 - 1835
(2018/04/11)
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- Reductive amination of levulinic acid to different pyrrolidones on Ir/SiO2-SO3H: Elucidation of reaction mechanism
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Levulinic acid (LA) transformation to different pyrrolidones via reductive amination was studied using an Ir/SiO2-SO3H catalyst in liquid phase. The effects of solvent, amine concentration, H2 partial pressure, catalyst mass, and reuse were studied. The spent catalysts were evaluated by DRIFTS to obtain evidence of the interaction of levulinic acid with aniline on the catalyst surface. The sulfonic groups on SiO2 improved the yield to pyrrolidones and avoided side reactions. A reaction mechanism is proposed where the reductive amination occurs between LA and amine towards an intermediate amine that is then cycled. The Gibbs free energy for the reaction mechanism was evaluated. Besides, the HOMO and LUMO of the amine reactants and intermediates using density functional theory (DFT) with the B3LYP-D3 method were theoretically determined to understand the rate-limiting and the cyclization steps.
- Martínez, José J.,Silva, Leonardo,Rojas, Hugo A.,Romanelli, Gustavo P.,Santos, Lucas A.,Ramalho, Teodorico C.,Brijaldo, María H.,Passos, Fabio B.
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p. 118 - 126
(2017/09/06)
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- Reductive amination/cyclization of levulinic acid to pyrrolidones: Versus pyrrolidines by switching the catalyst from AlCl3 to RuCl3 under mild conditions
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Herein the reductive amination/cyclization of levulinic acid using phenylsilane was presented to selectively produce pyrrolidones versus pyrrolidines under mild conditions by switching the catalyst from AlCl3 to RuCl3. Using AlCl3 as the catalyst, pyrrolidones were solely obtained at room temperature, while RuCl3 as the catalyst selectively afforded pyrrolidines in high yields at 45 °C.
- Liu, Zhimin,Wu, Cailing,Luo, Xiaoying,Zhang, Hongye,Liu, Xinwei,Ji, Guipeng,Liu, Zhenghui
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supporting information
p. 3525 - 3529
(2017/08/15)
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- One-Pot Selective Catalytic Synthesis of Pyrrolidone Derivatives from Ethyl Levulinate and Nitro Compounds
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N-substituted 5-methyl-2-pyrrolidones were prepared in a one-pot process starting from ethyl levulinate and nitro compounds in the presence of a nanosized Pt-based catalyst. Pt supported on TiO2nanotubes (Pt/TiO2-NT) catalyzed the synthesis of N-substituted 5-methyl-2-pyrrolidones through a cascade process involving the reduction of nitro compounds, formation of the intermediary imine, hydrogenation, and subsequent cyclization. A bifunctional metal–acid system was a suitable catalyst for the process. Pt supported on TiO2showed lower catalytic activity than Pt/TiO2-NT owing to the strong adsorption of nitro compounds during the first reaction step that poisoned the acidic sites and strongly decreased the rate of amination and cyclization. However, Pt/TiO2-NT with milder acid sites was less affected by the adsorption of nitro compounds and the full cascade process could proceed. The results indicate that the prepared Pt/TiO2-NT is a chemoselective and reusable catalyst that can be applied to the synthesis of a variety of N-substituted 5-methyl-2-pyrrolidones starting from nitro compounds with excellent yields in absence of an additional organic solvent under mild reaction conditions.
- Vidal, Juan D.,Climent, Maria J.,Corma, Avelino,Concepcion, Dr Patricia,Iborra, Sara
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p. 119 - 128
(2017/01/17)
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- Iridium-Catalyzed Reductive Amination of Levulinic Acid to Pyrrolidinones under H2 in Water
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The synthesis of pyrrolidinones from reductive amination of levulinic acid (LA) with primary amines is reported. Pyrrolidinones have various applications such as surfactants, pharmaceutical intermediates, dispersants, and solvents. The half-sandwich Cp*Ir complex (Cp* is 1,2,3,4,5-pentamethylcyclopenta-1,3-diene) coordinated by bipyridine ligand bearing both dimethylamino and ortho-hydroxyl groups showed high catalytic activity for the reductive amination of LA. A range of primary amines, such as aromatic and benzyl amines, were readily converted to corresponding pyrrolidinones in good yields.
- Xu, Zhanwei,Yan, Peifang,Jiang, Hong,Liu, Kairui,Zhang, Z. Conrad
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p. 581 - 585
(2017/05/29)
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- Method for preparing pyrrolidone by using levulinic acid
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The invention relates to a method for preparing pyrrolidone by using levulinic acid, belonging to the technical field of chemical intermediate production methods. According to the method, the levulinic acid is converted into N-substituted-5-methyl pyrroli
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Paragraph 0017; 0019-0048; 0062
(2017/08/29)
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- Lactate-Based Ionic Liquid Catalyzed Reductive Amination/Cyclization of Keto Acids under Mild Conditions: A Metal-Free Route to Synthesize Lactams
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Task-specific ionic liquids (ILs) have shown promising applications in catalysis. Herein we present lactate-based IL (e.g., 1-butyl-3-methylimidazolium lactate, [BMIm][Lac]) catalyzed reductive amination/cyclization of keto acids using triethoxysilane as a reducing agent, which provides a metal-free route to synthesis of lactams under mild conditions, even at room temperature. [BMIm][Lac] combined with (EtO)3SiH afforded a series of five- and six-membered lactams in good to excellent yields at 80 °C within 1 h, showing comparable performance to the best metal-based catalyst reported to date. The mechanism investigation indicated that the ILs (e.g., [BMIm][Lac]) served as a multifunctional catalyst, which could activate hydrosilanes and simultaneously catalyzed the cyclization of LA with amines.
- Wu, Cailing,Zhang, Hongye,Yu, Bo,Chen, Yu,Ke, Zhengang,Guo, Shien,Liu, Zhimin
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p. 7772 - 7776
(2017/11/10)
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- Selective and Efficient Iridium Catalyst for the Reductive Amination of Levulinic Acid into Pyrrolidones
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The catalytic reductive amination of levulinic acid (LA) into pyrrolidones with an iridium catalyst using H2 as hydrogen source is reported. The chemoselective iridium catalyst displayed high efficiency for the synthesis of a variety of N-substituted 5-methyl-2-pyrrolidones and N-arylisoindolinones. N-Substituted 5-methyl-2-pyrrolidone was also evaluated as a biosourced substitute solvent to NMP (N-methylpyrrolidone) in the catalytic arylation of 2-phenylpyridine.
- Wang, Shengdong,Huang, Haiyun,Bruneau, Christian,Fischmeister, Cédric
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p. 4150 - 4154
(2017/10/07)
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- Zirconium Oxide Supported Palladium Nanoparticles as a Highly Efficient Catalyst in the Hydrogenation–Amination of Levulinic Acid to Pyrrolidones
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The selective hydrogenation–amination of levulinic acid into pyrrolidones is regarded as one of the most important reactions to transform biomass-derived lignocellulose feedstocks into valuable chemicals. Here we report on ZrO2-supported Pd nanoparticles as a highly active, chemoselective, and reusable catalyst for the hydrogenation–amination of levulinic acid with H2 and various amines under mild reaction conditions. The Pd/ZrO2 catalyst exhibited a marked increase in activity compared with conventional Pd catalysts and a significant enhancement in pyrrolidone selectivity. The excellent catalytic performances are reasonably attributed to the ZrO2 support, which has strong Lewis acidity to enhance the hydrogenation–amination reaction and hinder side reactions.
- Zhang, Jian,Xie, Bin,Wang, Liang,Yi, Xianfeng,Wang, Chengtao,Wang, Guoxiong,Dai, Zhifeng,Zheng, Anmin,Xiao, Feng-Shou
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p. 2661 - 2667
(2017/07/28)
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- Visible-Light-Mediated Synthesis of Amidyl Radicals: Transition-Metal-Free Hydroamination and N-Arylation Reactions
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The development of photoredox reactions of aryloxy-amides for the generation of amidyl radicals and their use in hydroamination-cyclization and N-arylation reactions is reported. Owing to the ease of single-electron-transfer reduction of the aryloxy-amides, the organic dye eosin Y was used as the photoredox catalyst, which results in fully transition-metal-free processes. These transformations exhibit a broad scope, are tolerant to several important functionalities, and have been used in the late-stage modification of complex and high-value N-containing molecules.
- Davies, Jacob,Svejstrup, Thomas D.,Fernandez Reina, Daniel,Sheikh, Nadeem S.,Leonori, Daniele
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p. 8092 - 8095
(2016/07/16)
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- Synthesis of pyrrolidones and quinolines from the known biomass feedstock levulinic acid and amines
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The catalytic conversion of biomass-derived compounds into value-added products such as food additives, agrochemical components, and pharmaceutical formulations, is a promising and cost effective synthetic strategy. Here, we describe the synthesis of a variety of N-(alkyl, aryl)-5-methyl-2-pyrrolidones through the reductive amination of levulinic acid using formic acid as the hydrogen source. This system is catalyzed by 3.8 nm ruthenium nanoparticles that were prepared by thermal decomposition of [Ru3(CO)12] in solvent-free conditions. When the reactions were carried out without the catalyst, the pyrrolidones were obtained with low yield and poor selectivity. In addition, the reaction between levulinic acid and 2-ethynylaniline produced 2-(2,4-dimethylquinolin-3-yl) acetic acid (8) in mild and metal-free conditions with good yield. Furthermore, the synthesis of substituted quinolines was achieved through a condensation reaction between levulinic acid and different 2-alkynylanilines promoted by p-toluenesulfonic acid, this method is highlighted as a novel procedure for the preparation of quinolines.
- Ortiz-Cervantes, Carmen,Flores-Alamo, Marcos,García, Juventino J.
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supporting information
p. 766 - 771
(2016/02/05)
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- Reductive Amination/Cyclization of Keto Acids Using a Hydrosilane for Selective Production of Lactams versus Cyclic Amines by Switching of the Indium Catalyst
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Described herein is that the catalytic construction of N-substituted five- and six-membered lactams from keto acids with primary amines by reductive amination, using an indium/silane combination. This relatively benign and safe catalyst/reductant system tolerates the use of a variety of functional groups, especially ones that are reduction-sensitive. A direct switch from synthesizing lactams to synthesizing cyclic amines is achieved by changing the catalyst from In(OAc)3 to InI3. This conversion occurs by further reduction of the lactam using the indium/silane pair.
- Ogiwara, Yohei,Uchiyama, Takuya,Sakai, Norio
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supporting information
p. 1864 - 1867
(2016/02/03)
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- Catalytic Olefin Hydroamidation Enabled by Proton-Coupled Electron Transfer
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Here we report a ternary catalyst system for the intramolecular hydroamidation of unactivated olefins using simple N-aryl amide derivatives. Amide activation in these reactions occurs via concerted proton-coupled electron transfer (PCET) mediated by an excited state iridium complex and weak phosphate base to furnish a reactive amidyl radical that readily adds to pendant alkenes. A series of H-atom, electron, and proton transfer events with a thiophenol cocatalyst furnish the product and regenerate the active forms of the photocatalyst and base. Mechanistic studies indicate that the amide substrate can be selectively homolyzed via PCET in the presence of the thiophenol, despite a large difference in bond dissociation free energies between these functional groups.
- Miller, David C.,Choi, Gilbert J.,Orbe, Hudson S.,Knowles, Robert R.
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supporting information
p. 13492 - 13495
(2015/11/09)
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- Chemicals from Biomass: Chemoselective Reductive Amination of Ethyl Levulinate with Amines
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N-substituted-5-methyl-2-piyrrolidones have been obtained by reductive amination of ethyl levulinate with amines in the presence of H2 as reducing agent under solvent-free conditions. The process involves as a first step the formation of an imine intermediate followed by hydrogenation of the imine group and subsequent cyclization into pyrrolidone. Pt/TiO2 with Pt crystal faces decorated with TiOx is a very active and chemoselective catalyst, being possible to achieve high conversion and selectivity to the corresponding N-substituted-5-methyl-2-pyrrolidones even when other groups susceptible of hydrogenation such as vinyl, carbonyl, or cyano groups are present in the amine moiety. A kinetic study showed that the reaction-controlling step is the formation of the imine intermediate. The rate of formation is enhanced by the presence of protonic acid sites generated on the support by hydrogen dissociation on the metal, resulting in a true bifunctional catalyst for the reaction.
- Vidal, Juan D.,Climent, Maria J.,Concepcion, Patricia,Corma, Avelino,Iborra, Sara,Sabater, Maria J.
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p. 5812 - 5821
(2015/10/12)
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- Boron-Catalyzed N-Alkylation of Amines using Carboxylic Acids
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A boron-based catalyst was found to catalyze the straightforward alkylation of amines with readily available carboxylic acids in the presence of silane as the reducing agent. Various types of primary and secondary amines can be smoothly alkylated with good selectivity and good functional-group compatibility. This metal-free amine alkylation was successfully applied to the synthesis of three commercial medicinal compounds, Butenafine, Cinacalcet. and Piribedil, in a one-pot manner without using any metal catalysts.
- Fu, Ming-Chen,Shang, Rui,Cheng, Wan-Min,Fu, Yao
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p. 9042 - 9046
(2015/08/03)
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- Highly efficient and versatile synthesis of lactams and N -heterocycles via Al(OTf)3-catalyzed cascade cyclization and ionic hydrogenation reactions
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The discovery and development of an efficient and versatile method for the synthesis of N-substituted lactams is described. Pyrrolindinones, piperidones, and structurally related heterocycles were formed by Al(OTf)3- catalyzed cascade cyclizati
- Qi, Jianguo,Sun, Chenbin,Tian, Yulin,Wang, Xiaojian,Li, Gang,Xiao, Qiong,Yin, Dali
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supporting information
p. 190 - 192
(2014/01/23)
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- Heterogeneous Pt catalysts for reductive amination of levulinic acid to pyrrolidones
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Supported platinum catalysts have been studied for the reductive amination of levulinic acid (LA) by H2 to N-alkyl-5-methyl-2-pyrrolidones under solvent-free conditions. The activity depends on the type of metal (Pt, Re, Pd, Rh, Ru, Cu, Ni), support material, and coloaded oxides of transition metals (V, Cr, Mo, W, Re). In 24 kinds of catalyst tested, Pt and MoOX (molybdenum oxide) coloaded TiO2 (Pt-MoOX/TiO2) shows the highest activity. Pt-MoOX/TiO2 is effective for reductive amination of LA with wide varieties of amines under mild conditions (3 bar of H2, 100 °C, solvent-free) to give high isolated yield of pyrrolidinones and shows higher turnover number (TON) than previously reported catalysts for reductive amination of LA with an aliphatic amine. The catalyst can be separated from the reaction mixture by filtration, and the recovered catalyst can be reused. This is the first general and reusable heterogeneous catalytic system for the reductive amination of LA. On the basis of mechanistic studies, high activity of Pt-MoOX/TiO2 can be attributed to acid-base interaction between the acid sites of Pt-MoOX/TiO2 and carboxyl groups in LA and an intermediate.
- Touchy, Abeda Sultana,Hakim Siddiki,Kon, Kenichi,Shimizu, Ken-Ichi
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p. 3045 - 3050
(2015/01/09)
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- Catalyst-free transformation of levulinic acid into pyrrolidinones with formic acid
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Levulinic acid (LA) is transformed into pyrrolidinones by formic acid in DMSO without a catalyst. Mechanistic studies suggest the involvement of an iminium intermediate and a rate-limiting hydride transfer step.
- Wei, Yawen,Wang, Chao,Jiang, Xue,Xue, Dong,Liu, Zhao-Tie,Xiao, Jianliang
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supporting information
p. 1093 - 1096
(2014/03/21)
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- Silver-catalyzed radical aminofluorination of unactivated alkenes in aqueous media
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We report herein a mild and catalytic intramolecular aminofluorination of unactivated alkenes. Thus, with the catalysis of AgNO3, the reactions of various N-arylpent-4-enamides with Selectfluor reagent in CH 2Cl2/H2/
- Li, Zhaodong,Song, Liyan,Li, Chaozhong
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p. 4640 - 4643
(2013/05/09)
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- Highly efficient transformation of levulinic acid into pyrrolidinones by iridium catalysed transfer hydrogenation
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Levulinic acid (LA) is transformed into pyrrolidinones via iridium-catalysed reductive amination using formic acid as the hydrogen source under aqueous conditions. The catalytic system is the most active and performs under the mildest conditions ever reported for the reductive amination of LA.
- Wei, Yawen,Wang, Chao,Jiang, Xue,Xue, Dong,Li, Jia,Xiao, Jianliang
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supporting information
p. 5408 - 5410
(2013/07/05)
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- Ruthenium-catalyzed conversion of levulinic acid to pyrrolidines by reductive amination
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Combo deal: An aqueous solution of levulinic acid (LA) and formic acid (FA) derived from biomass-based carbohydrates can be converted efficiently to pyrrolidines via a ruthenium catalyst without need for an energy-intensive separation of LA or an external H2 source. The ruthenium catalyst combines two processes: decomposition of FA to H2 and reductive amination of LA with an amine. Copyright
- Huang, Yao-Bing,Dai, Jian-Jun,Deng, Xiao-Jian,Qu, Yan-Chao,Guo, Qing-Xiang,Fu, Yao
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experimental part
p. 1578 - 1581
(2012/03/22)
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- Hydrogen-independent reductive transformation of carbohydrate biomass into γ-valerolactone and pyrrolidone derivatives with supported gold catalysts
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A golden opportunity: A highly robust catalyst system consisting of gold nanoparticles supported on acid-tolerant ZrO2 promoted the conversion of biomass-derived levulinic acid (1) and formic acid (2) into γ-valerolactone without the use of an external H2 supply (see scheme, red). The Au/ZrO2 catalyst was also used for the direct one-pot synthesis of highly valuable pyrrolidone derivatives from 1, 2, and primary amines (see scheme, blue).
- Du, Xian-Long,He, Lin,Zhao, She,Liu, Yong-Mei,Cao, Yong,He, He-Yong,Fan, Kang-Nian
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supporting information; experimental part
p. 7815 - 7819
(2011/10/08)
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- Copper(II) carboxylate-promoted intramolecular carboamination of alkenes for the synthesis of polycyclic lactams
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The copper(II) carboxylate-promoted intramolecular carboamination reactions of variously substituted y-alkenyl amides have been investigated. These oxidative cyclization reactions efficiently provide polycyclic lactams, useful intermediates in nitrogen he
- Fuller, Peter H.,Chemler, Sherry R.
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p. 5477 - 5480
(2008/09/17)
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- Tetrafluoro-IBA and-IBX: Hypervalent iodine reagents
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Fluorine makes the difference: FIBX (see structure), the tetrafluoro derivative of the hypervalent iodine reagent, is more soluble and has higher reactivity than its nonfluorinated counterpart. An efficient synthesis of FIBX and initial reactions are presented. Some of these reactions can be conducted in standard organic solvents. Owing to the increased reactivity, new transformations and catalytic reactions may be possible. (Chemical Equation Presented).
- Richardson, Robert D.,Zayed, Jameel M.,Altermann, Sabine,Smith, Daniel,Wirth, Thomas
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p. 6529 - 6532
(2008/09/16)
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- Phosphine gold(I)-catalyzed hydroamination of alkenes under thermal and microwave-assisted conditions
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Phosphine gold(I) complexes catalyzed isomerization of terminal alkenes and hydroamination of unactivated alkenes under thermal and microwave-assisted conditions. This is the first example of the use of microwave radiation as a heat source for gold(I)-catalyzed organic reactions.
- Liu, Xin-Yuan,Li, Cheng-Hui,Che, Chi-Ming
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p. 2707 - 2710
(2007/10/03)
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- Facile cyclization of amidyl radicals generated from N-acyltriazenes
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N-Acyltriazenes serve as a tin-free and initiator-free source for amidyl radicals. Thermal decomposition of N,N′-diaryl-N-(4-pentenoyl)triazenes in refluxing toluene led to the formation of monocyclic and tricyclic lactams in satisfactory yields via 5-exo amidyl radical cyclization.
- Lu, Hongjian,Li, Chaozhong
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p. 5983 - 5985
(2007/10/03)
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- Production of 5-methyl-N-aryl-2-pyrrolidone and 5-methyl-N-cycloalkyl-2-pyrrolidone by reductive amination of levulinic acid with aryl amines
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This invention relates to a process for producing 5-methyl-N-aryl-2-pyrrolidone and 5-methyl-N-cycloalkyl-2-pyrrolidone by reductive amination of levulinic acid or its derivatives with aryl amines, ammonia or ammonium hydroxide utilizing a metal catalyst,
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Page/Page column 12-13
(2008/06/13)
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- PRODUCTION OF N-ARYL-2-LACTAM AND N-ALKYL-2-LACTAM BY REDUCTIVE AMINATION OF LACTONES WITH ARYL AND ALKYL NITRO COMPOUNDS
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This invention relates to a process for producing N-aryl-2-lactams, N-alkyl-2-lactams, and N-cycloalkyl-2-lactams by reductive amination of lactones with aryl or alkyl nitro compounds utilizing a metal catalyst, which is optionally supported.
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- PRODUCTION OF 5-METHYL-N-ARYL-2-PYRROLIDONE AND 5-METHYL-N-ALKYL-2-PYRROLIDONE BY REDUCTIVE AMINATION OF LEVULINIC ACID WITH NITRO COMPOUNDS
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This invention relates to a process for producing 5-methyl-N-aryl-2-pyrrolidone, 5-methyl-N-cycloalkyl-2-pyrrolidone, and 5-methyl-N-alkyl-2-pyrrolidone by reductive amination of levulinic acid with nitro compounds utilizing a metal catalyst, which is opt
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- Production of 5-methyl-N-aryl-2-pyrrolidone and 5-methyl-N-alkyl-2-pyrrolidone by reductive amination of levulinic acid esters with nitro compounds
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This invention relates to a process for producing 5-methyl-N-aryl-2-pyrrolidone, 5-methyl-N-cycloalkyl-2-pyrrolidone, and 5-methyl-N-alkyl-2-pyrrolidone by reductive amination of levulinic acid esters with nitro compounds utilizing a metal catalyst, which
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- Production of 5-mehyl-N-aryl-2-pyrrolidone and 5-methyl-N-alkyl-2-pyrrolidone by reductive of levulinic acid esters with aryl and alkyl amines
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This invention relates to a process for producing 5-methyl-N-aryl-2-pyrrolidone, 5-methyl-N-alkyl-2-pyrrolidone, and 5-methyl-N-cycloalkyl-2-pyrrolidone by reductive amination of levulinic acid esters with aryl or alkyl amines utilizing a metal catalyst, which is optionally supported.
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- Bronsted acid-catalyzed intramolecular hydroamination of protected alkenylamines. Synthesis of pyrrolidines and piperidines.
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[reaction: see text]. The cyclization of aminoalkenes bearing an electron-withdrawing group on the nitrogen atom was catalyzed by triflic or sulfuric acid in toluene. Pyrrolidines and piperidines were formed in excellent yields. N-phenylanilides also underwent cyclization to form gamma-lactams.
- Schlummer, Bjoern,Hartwig, John F
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p. 1471 - 1474
(2007/10/03)
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- Iodine(V) reagents in organic synthesis. Part 3. New routes to heterocyclic compounds via o-iodoxybenzoic acid-mediated cyclizations: Generality, scope, and mechanism
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The discovery and development of the o-iodoxybenzoic acid (IBX) reaction with certain unsaturated N-aryl amides (anilides) to form heterocycles are described. The application of the method to the synthesis of δ-lactams, cyclic urethanes, hydroxy amines, and amino sugars among other important building blocks and intermediates is detailed. In addition to the generality and scope of this cyclization reaction, this article describes a number of mechanistic investigations suggesting a single electron transfer from the anilide functionality to IBX and implicating a radical-based mechanism for the reaction.
- Nicolaou,Baran,Zhong,Barluenga,Hunt,Kranich,Vega
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p. 2233 - 2244
(2007/10/03)
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- REACTION OF OXIRANES WITH DIANIONS OF SECONDARY AMINES. NEW ENTRY TO 5-ALKYLSUBSTITUTED γ-LACTAMS
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The oxirane ring cleavage with dilithiated secondary amides was accelerated by the addition of boron trifluoride-etherate to afford γ-hydroxyamides, which were transformed into 5-alkylsubstituted γ-lactams via an intramolecular N-alkylation reaction.
- Takahata, Hiroki,Wang, Eng-Chi,Yamazaki, Takao
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p. 1159 - 1166
(2007/10/02)
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