- Dehydrogenation/(3+2) Cycloaddition of Saturated Aza-Heterocycles via Merging Organic Photoredox and Lewis Acid Catalysis
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Herein, we report a photoinduced dehydrogenation/(3+2) cycloaddition reaction by merging organic photoredox and Lewis acid catalysis, providing a straightforward and efficient approach for directly installing a benzofuran skeleton on the saturated aza-heterocycles. In this protocol, we also describe a novel organic photocatalyst (t-Bu-DCQ) with the advantages of a wider redox potential, easy synthesis, and a low price. Furthermore, the stepwise activation mechanism of dual C(sp3)-H bonds was demonstrated by a series of experimental and computational studies.
- Xiao, Teng-Fei,Zhang, Yi-Fan,Hou, Wen-Tao,Yan, Pen-Ji,Hai, Jun,Xu, Peng-Fei,Xu, Guo-Qiang
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supporting information
p. 8942 - 8946
(2021/11/24)
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- Organic photoredox catalytic α-C(sp3)-H phosphorylation of saturated: Aza -heterocycles
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A metal-free C(sp3)-H phosphorylation of saturated aza-heterocycles via the merger of organic photoredox and Br?nsted acid catalyses was established under mild conditions. This protocol provided straightforward and economic access to a variety of valuable α-phosphoryl cyclic amines by using commercially available diarylphosphine oxide reagents. In addition, the D-A fluorescent molecule DCQ was used for the first time as a photocatalyst and exhibited an excellent photoredox catalytic efficiency in this transformation. A series of mechanistic experiments and DFT calculations demonstrated that this transformation underwent a sequential visible light photoredox catalytic oxidation/nucleophilic addition process.
- Yi, Ming-Jun,Xiao, Teng-Fei,Li, Wen-Hui,Zhang, Yi-Fan,Yan, Pen-Ji,Zhang, Baoxin,Xu, Peng-Fei,Xu, Guo-Qiang
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supporting information
p. 13158 - 13161
(2021/12/16)
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- Tropane alkaloid compounds and method of manufacturing using sequential oxidation reactions
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The present invention relates to a tropane alkaloid compound sequentially using an oxidative Mannich ring reaction and a method for producing the same. The present invention provides a tropane alkaloid compound having a structure of chemical formula 1 in
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Paragraph 0098; 0104-0108
(2020/06/16)
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- Dialkylterphenyl Phosphine-Based Palladium Precatalysts for Efficient Aryl Amination of N-Nucleophiles
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A series of 2-aminobiphenyl palladacycles supported by dialkylterphenyl phosphines, PR2Ar′ (R=Me, Et, iPr, Cyp (cyclopentyl), Ar′=ArDipp2, ArXyl2f, Dipp (2,6-C6H3-(2,6-C6H3-(CHMe2)2)2), Xyl=xylyl) have been prepared and structurally characterized. Neutral palladacycles were obtained with less bulky terphenyl phosphines (i.e., Me and Et substituents) whereas the largest phosphines provided cationic palladacycles in which the phosphines adopted a bidentate hemilabile k1-P,η1-Carene coordination mode. The influence of the ligand structure on the catalytic performance of these Pd precatalysts was evaluated in aryl amination reactions. Cationic complexes bearing the phosphines PiPr2ArXyl2 and PCyp2ArXyl2 were the most active of the series. These precatalysts have demonstrated a high versatility and efficiency in the coupling of a variety of nitrogen nucleophiles, including secondary amines, alkyl amines, anilines, and indoles, with electronically deactivated and ortho-substituted aryl chlorides at low catalyst loadings (0.25–0.75 mol % Pd) and without excess ligand.
- Rama, Raquel J.,Maya, Celia,Nicasio, M. Carmen
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supporting information
p. 1064 - 1073
(2020/01/25)
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- Methyl-α-d-glucopyranoside as Green Ligand for Selective Copper-Catalyzed N-Arylation
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In the selective N-arylation of amines or azoles with aryl halidesa-, methyl-α-d-glucopyranoside (MG) was found to function as a green ligand of copper powder. In addition, nitrogen heterocyclic amine compounds can also undergo the N-arylation coupling with heterocyclic aryl chlorides. This process allows access to a variety of aromatic amines and aryl azoles under mild reaction conditions, has good tolerance, and proceeds in moderate to high yield.
- Chen, Fengyang,Chen, Guoliang,Chen, Yuanguang,Du, Fangyu,Zhou, Qifan
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p. 4590 - 4600
(2019/12/11)
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- Cu(II)-catalyzed C-N coupling of (hetero)aryl halides and N-Nucleophiles promoted by α-benzoin oxime
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We first reported the new application of a translate metal chelating ligand α-benzoin oxime for improving Cu-catalyzed C-N coupling reactions. The system could catalyse coupling reactions of (hetero)aryl halides with a wide of nucleophiles (e.g., azoles, piperidine, pyrrolidine and amino acids) in moderate to excellent yields. The protocol allows rapid access to the most common scaαolds found in FDA-approved pharmaceuticals.
- Yuan, Chunling,Zhang, Lei,Zhao, Yingdai
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- Utilization of Cyclic Amides as Masked Aldehyde Equivalents in Reductive Amination Reactions
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An operationally simple protocol has been discovered that couples primary or secondary amines with N-aryl-substituted lactams to deliver differentiated diamines in moderate to high yields. The process allows for the partial reduction of a lactam in the presence of Cp2ZrHCl (Schwartz's reagent), followed by a reductive amination between the resulting hemiaminal and primary or secondary amine. These reactions can be telescoped in a one-pot fashion to significantly simplify the operation. The scope of amines and substituted lactams of various ring sizes was demonstrated through the formation of a range of differentiated diamine products. Furthermore, this methodology was expanded to include N-aryl pyrrolidinone substrates with an enantiopure ester group at the 5-position, and α-amino piperidinones were prepared with complete retention of stereochemical information. The development of this chemistry has enabled the consideration of lactams as useful synthons.
- Prince, Robin J.,Gao, Fang,Pazienza, Jessica E.,Marx, Isaac E.,Schulz, Jurgen,Hopkins, Brian T.
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p. 7936 - 7949
(2019/06/27)
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- Construction of 8-Azabicyclo[3.2.1]octanes via Sequential DDQ-Mediated Oxidative Mannich Reactions of N-Aryl Pyrrolidines
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A concise synthesis of 8-azabicyclo[3.2.1]octanes via sequential oxidative Mannich reactions is described. This approach involves an intermolecular oxidative Mannich coupling reaction between N-aryl pyrrolidines with TMS enol ether and a subsequent intramolecular oxidative Mannich cyclization of the corresponding silyl enol ether. DDQ is used as a key oxidant for both reactions.
- Jo, Hanbyeol,Hassan, Ahmed H. E.,Jung, Seung Young,Lee, Jae Kyun,Cho, Yong Seo,Min, Sun-Joon
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supporting information
p. 1175 - 1178
(2018/02/23)
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- Transition-Metal-Free Selective C?H Benzylation of Tertiary Arylamines by a Dearomatization-Aromatization Sequence
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Due to the significance of hybrid systems in drug discovery, there is an urgent need to assemble multiple biologically active ingredients into a single molecule. Here, we report a general transition-metal-free selective C?H benzylation of tertiary arylamines in good to excellent yields with a broad substrate scope and high functional-group tolerance under mild conditions. Besides arylamines, some other benzene derivatives also readily furnished the corresponding diaryl methane derivatives with this protocol. A series of control experiments and theoretical calculations indicated that this transition-metal-free reaction is a dearomatization-aromatization process.
- Xu, Guo-Qiang,Feng, Zhi-Tao,Xu, Ji-Tao,Wang, Zhu-Yin,Qin, Yong,Xu, Peng-Fei
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supporting information
p. 13778 - 13782
(2018/09/14)
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- Discovery of N-(Naphthalen-1-yl)-N′-alkyl Oxalamide Ligands Enables Cu-Catalyzed Aryl Amination with High Turnovers
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A class of N-(naphthalen-1-yl)-N′-alkyl oxalamides have been proven to be powerful ligands, making a coupling reaction of (hetero)aryl iodides with primary amines proceed at 50 °C with only 0.01 mol % of Cu2O and ligand as well as a coupling reaction of (hetero)aryl bromides with primary amines and ammonia at 80 °C with only 0.1 mol % of Cu2O and ligand. A wide range of coupling partners work well under these conditions, thereby providing an easy to operate method for preparing (hetero)aryl amines.
- Gao, Jie,Bhunia, Subhajit,Wang, Kailiang,Gan, Lu,Xia, Shanghua,Ma, Dawei
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supporting information
p. 2809 - 2812
(2017/06/07)
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- Modular Synthesis of Biaryl-Substituted Phosphine Ligands: Application in Microwave-Assisted Palladium-Catalyzed C-N Cross-Coupling Reactions
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Biaryl-substituted monophosphine-based ligands have been synthesized by transition-metal-free "ARYNE" cross-coupling reaction of aryllithiums with 1,2-dibromobenzene and subsequent regioselective functionalization through bromine-lithium interconversion. These ligands were employed in palladium-catalyzed C-N bond-forming reactions. The reaction was found to be general with wide substrate applicability. A wide variety of both primary and secondary amines were successfully coupled with an array of differently substituted halobenzenes under microwave irradiation to give the expected products in good to excellent yields. A number of biaryl-substituted phosphine ligands screened for the coupling reaction showed that steric bulk and the electronic properties of substituents on phosphorus play a crucial role in governing the catalytic activity of C-N cross-coupling reactions. Biaryl-substituted monophosphines have been synthesized by transition metal free ARYNE cross-coupling reactions and subsequent regioselective functionalization through bromine-lithium interconversion. These ligands were employed in palladium-catalyzed C-N bond-forming reactions.
- Singh, Chandani,Rathod, Jayant,Jha, Vishwajeet,Panossian, Armen,Kumar, Pradeep,Leroux, Frédéric R.
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p. 6515 - 6525
(2015/10/19)
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- Cycloaddition of Enamine and Iminium Ion Intermediates Formed in the Reaction of N -Arylpyrrolidines with T-HYDRO
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The reaction of N-arylpyrrolidine derivatives with 70% aqueous tert-butyl hydroperoxide (T-HYDRO) in the presence of NaOAc·3H2O gives tetracyclic amines in 59-78% yields via cycloaddition of the corresponding iminium ion and enamine intermediates formed in situ in cyclohexane solvent. The iminium ion intermediate reacts with t-BuOK in methanol to give the corresponding cyclic amides in 85-88% yields or undergoes alkylation to give the corresponding nitromethyl product in 74-79% yields using t-BuOK and nitromethane in methanol.
- Rao, Gunda Ananda,Periasamy, Mariappan
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p. 2231 - 2236
(2015/09/28)
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- N-(1-Oxy-2-picolyl)oxalamic Acid as an Efficient Ligand for Copper-Catalyzed Amination of Aryl Iodides at Room Temperature
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N-(1-Oxy-pyridin-2-ylmethyl)oxalamic acid was identified as efficient ligand for CuI-catalyzed amination of aryl halides at room temperature. In our catalytic system, N-arylation of cyclic secondary amines, primary amines, amino acids, and ammonia proceeded with moderate to excellent yields and high functional group tolerance.
- Wang, Yongbin,Ling, Jing,Zhang, Yu,Zhang, Ao,Yao, Qizheng
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p. 4153 - 4161
(2015/07/01)
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- CuI/DMPAO-catalyzed N-arylation of acyclic secondary amines
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DMPAO has been found to be a powerful ligand to enable copper-catalyzed coupling of aryl halides with aliphatic acyclic secondary amines take place under relatively mild conditions, and coupling of aryl halides with primary amines and cyclic secondary amines proceeds at low catalyst loading.
- Zhang, Yu,Yang, Xinye,Yao, Qizheng,Ma, Dawei
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supporting information; experimental part
p. 3056 - 3059
(2012/07/28)
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- Synthesis of a sensitive and selective potassium-sensing fluoroionophore
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"Chemical Equation Presented" An efficient synthesis is reported that delivers in 5 steps and 52% overall yield a new structurally simplified fluorescent K+ sensor with improved K+ sensitivity and selectivity over existing K+ sensors. The synthesis procedure utilizes a new template-directed oxidative C-N bond-forming macrocyclization reaction and reports new approaches to Pd(O), Sandmeyer-like and metal-free aminoarylations, as well as organotitanium additions to vinylogous sulfonates.
- Carpenter, Richard D.,Verkman
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supporting information; experimental part
p. 1160 - 1163
(2010/05/18)
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- Cadmium(II)-catalyzed C-N cross-coupling of amines with aryl iodides
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Cadmium diacetate dihydrate [Cd(OAc)2·2H2O] in combination with ethylene glycol catalyzes efficiently the C-N cross-coupling of amines with aryl iodides by a benzyne mechanism. Alkyl, aryl and heterocyclic amines are compatible with this system affording the aminated products in high to excellent yield.
- Rout, Laxmidhar,Saha, Prasenjit,Jammi, Suribabu,Punniyamurthy, Tharmalingam
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supporting information; experimental part
p. 395 - 398
(2009/04/10)
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- The use of palladium chloride as a precatalyst for the amination of aryl bromides
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The use of palladium chloride as a precatalyst for the amination of aryl bromides is reported. To overcome the poor solubility of palladium chloride in commonly used solvents, a procedure was developed in which PdCl2 was preheated with neat amine in the presence of a phosphine ligand before the addition of the other reaction components. This protocol is effective for a broad range of substrate combinations using several types of phosphine ligands.
- Zhang, Xiao-Xiang,Harris, Michele C.,Sadighi, Joseph P.,Buchwald, Stephen L.
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p. 1799 - 1805
(2007/10/03)
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- Simple, efficient catalyst system for the palladium-catalyzed amination of aryl chlorides, bromides, and triflates
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Palladium complexes supported by (o-biphenyl)P(t-Bu)2 (3) or (o- biphenyl)PCy2 (4) are efficient catalysts for the catalytic amination of a wide variety of aryl halides and triflates. Use of ligand 3 allows for the room-temperature catalytic amination of many aryl chloride, bromide, and triflate substrates, while ligand 4 is effective for the amination of functionalized substrates or reactions of acyclic secondary amines. The catalysts perform well for a large number of different substrate combinations at 80-110 °C, including chloropyridines and functionalized aryl halides and triflates using 0.5-1.0 mol % Pd; some reactions proceed efficiently at low catalyst levels (0.05 mol % Pd). These ligands are effective for almost all substrate combinations that have been previously reported with various other ligands, and they represent the most generally effective catalyst system reported to date. Ligands 3 and 4 are air-stable, crystalline solids that are commercially available. Their effectiveness is believed to be due to a combination of steric and electronic properties that promote oxidative addition, Pd-N bond formation, and reductive elimination.
- Wolfe, John P.,Tomori, Hiroshi,Sadighi, Joseph P.,Yin, Jingjun,Buchwald, Stephen L.
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p. 1158 - 1174
(2007/10/03)
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- Direct Substitution of Aromatic Ethers by Lithium Amides. A New Aromatic Amination Reaction
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Reaction of lithiated dialkylamines with methoxy aromatics in refluxing THF leads to products resulting from a direct ipso-substitution.Especially with lithiated secondary amines high conversions and selectivities are achieved.Sulfonyl-substituted aromatics react equally well, but halogenated aromatics give rise to side-products arising from a competing pathway via aryne intermediates.The scope and mechanistic implications of this novel nucleophilic amination reaction are described.
- Hoeve, Wolter ten,Kruse, Chris, G.,Luteyn, Jan M.,Thiecke, Janet R. G.,Wynberg, Hans
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p. 5101 - 5106
(2007/10/02)
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- Synthesis of Pyrrolidines and Pyrrolidinones by the Rhodium Complex Catalyzed Cyclization of Unsaturated Amines
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N-Allylic arylamines react with carbon monoxide, sodium borohydride, 2-propanol, and catalytic amounts of the zwitterionic complex η6-C6H6BPh3-Rh(COD)+ (1), to form pyrrolidines as the main products in most cases.Pyrrolidinones result from N-allylic alkylamines.An alternate route to the lactams from N-allylic alkylamines involves synthesis gas instead of CO/NaBH4, together with the dual catalytic system 1/2.Complementary to the N-allylic arylamine route to pyrrolidines with NaBH4 and 1 is the use of synthesis gas, 1, and 1,4-bis(diphenylphosphino)butane.
- Zhou, Jian-Qiang,Alper, Howard
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p. 3328 - 3331
(2007/10/02)
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- A NEW AND FACILE SYNTHESIS OF N-SUBSTITUTED PYRROLIDINE OF AMINES WITH AQUEOUS SUCCINALDEHYDE USING TETRACARBONYLHYDRIDOFERRATE, HFe(CO)4(1-), AS A HIGHLY SELECTIVE REDUCING AGENT.
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Ethanolic tetracarbonylhydridoferrate combined with aqueous succinaldehyde is very efficient for the selective transformation of an amino group into a pyrrolidine ring.A large variety of both aliphatic and aromatic amines react with aqueous succinaldehyde in the presence of tetracarbonylhydridoferrate at room temperature under carbon monoxide to give the corresponding N-alkyl- and N-arylpyrrolidines in good to excellent yields.
- Shim, Sang Chul,Huh, Keun Tai,Park, Woo Hiun
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p. 259 - 264
(2007/10/02)
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