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1.
Hai‐Tao Tang Yun‐Bing Zhou Yu Zhu Hong‐Chao Sun Min Lin Prof. Zhuang‐Ping Zhan 《化学:亚洲杂志》2014,9(5):1278-1281
An efficient Cs2CO3‐promoted synthesis of α‐amino ketones using hydrazines, aldehydes, and α‐haloketones as starting materials through a cascade condensation/nucleophilic substitution/N? N bond cleavage route is developed. The carbonyl group plays a key role in this novel N? N bond cleavage process. 相似文献
2.
Efficient Synthesis of 1,2,3‐Triazoles by Copper‐Mediated CN and NN Bond Formation Starting From N‐Tosylhydrazones and Amines 下载免费PDF全文
Zhengkai Chen Qiangqiang Yan Hong Yi Zhanxiang Liu Prof. Dr. Aiwen Lei Prof. Dr. Yuhong Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(42):13692-13697
An effective copper‐mediated synthesis of 1,5‐dialkyl‐4‐aryl‐1,2,3‐triazoles and 1,4‐dialkyl‐5‐aryl‐1,2,3‐triazoles has been achieved by the use of different N‐tosylhydrazones and alkyl amines. The scope of the substrates could be extended from anilines to aliphatic amines when 30 mol % amino acid is added into the reaction mixture. This methodology exhibits many notable features, such as broad substrates scope, high efficiency, and good regioselectivity. Preliminary mechanistic studies indicated that the reaction probably proceeded through a 1‐tosyl‐2‐vinyldiazene intermediate and subsequent aza‐Michael addition and N?N bond formation process. 相似文献
3.
Copper‐Catalyzed Aerobic Oxidative NS Bond Functionalization for CS Bond Formation: Regio‐ and Stereoselective Synthesis of Sulfones and Thioethers 下载免费PDF全文
Xianwei Li Yanli Xu Dr. Wanqing Wu Chang Jiang Dr. Chaorong Qi Prof. Dr. Huanfeng Jiang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(26):7911-7915
A regio‐ and stereoselective synthesis of sulfones and thioethers by means of CuI‐catalyzed aerobic oxidative N?S bond cleavage of sulfonyl hydrazides, followed by cross‐coupling reactions with alkenes and aromatic compounds to form the C?S bond, is described herein. N2 and H2O are the byproducts of this transformation, thus offering an environmentally benign process with a wide range of potential applications in organic synthesis and medicinal chemistry. 相似文献
4.
Manganese‐Catalyzed Dehydrogenative [4+2] Annulation of NH Imines and Alkynes by CH/NH Activation 下载免费PDF全文
Ruoyu He Prof. Dr. Zhi‐Tang Huang Prof. Dr. Qi‐Yu Zheng Prof. Dr. Congyang Wang 《Angewandte Chemie (International ed. in English)》2014,53(19):4950-4953
Described herein is a manganese‐catalyzed dehydrogenative [4+2] annulation of N? H imines and alkynes, a reaction providing highly atom‐economical access to diverse isoquinolines. This transformation represents the first example of manganese‐catalyzed C? H activation of imines; the stoichiometric variant of the cyclomanganation was reported in 1971. The redox neutral reaction produces H2 as the major byproduct and eliminates the need for any oxidants, external ligands, or additives, thus standing out from known isoquinoline synthesis by transition‐metal‐catalyzed C? H activation. Mechanistic studies revealed the five‐membered manganacycle and manganese hydride species as key reaction intermediates in the catalytic cycle. 相似文献
5.
Dr. Rishikesh Narayan Dr. Kiran Matcha Dr. Andrey P. Antonchick 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(42):14678-14693
The formation of C?C bonds embodies the core of organic chemistry because of its fundamental application in generation of molecular diversity and complexity. C?C bond‐forming reactions are well‐known challenges. To achieve this goal through direct functionalization of C?H bonds in both of the coupling partners represents the state‐of‐the‐art in organic synthesis. Oxidative C?C bond formation obviates the need for prefunctionalization of both substrates. This Minireview is dedicated to the field of C?C bond‐forming reactions through direct C?H bond functionalization under completely metal‐free oxidative conditions. Selected important developments in this area have been summarized with representative examples and discussions on their reaction mechanisms. 相似文献
6.
Ln[N(SiMe3)2]3‐Catalyzed Cross‐Diinsertion of CN/CC into an NH Bond: Facile Synthesis of 1,2,4‐Trisubstituted Imidazoles from Propargylamines and Nitriles 下载免费PDF全文
Longcheng Hong Yinlin Shao Lixin Zhang Prof. Dr. Xigeng Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8551-8555
A lanthanide‐catalyzed sequential insertion of C?N and C?C into an N?H bond is presented. The convenient reaction, which proceeds under mild conditions, is an efficient method for preparing 1,2,4‐trisubstituted imidazoles directly from readily available propargylamines and nitriles. 相似文献
7.
Rhodium(III)‐Catalyzed CH Activation and Indole Synthesis With Hydrazone as an Auto‐Formed and Auto‐Cleavable Directing Group 下载免费PDF全文
Liyao Zheng Prof. Dr. Ruimao Hua 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2352-2356
An efficient, practical, and external‐oxidant‐free indole synthesis from readily available aryl hydrazines was developed, by using hydrazone as a directing group for RhIII‐catalyzed C?H activation and alkyne annulation. The hydrazone group was formed by in situ condensation of hydrazines and C?O source, whereas its N?N bond was served as an internal oxidant, for which we termed it as an auto‐formed and auto‐cleavable directing group (DGauto). This method needs no step for pre‐installation and post‐cleavage of the directing group, making it a quite easily scalable approach to access unprotected indoles with high step economy. The DGauto strategy was also applicable for isoquinoline synthesis. In addition, synthetic utilities of this chemistry for rapid assembly of π‐extended nitrogen‐doped polyheterocycles and bioactive molecules were demonstrated. 相似文献
8.
Dipl.‐Chem. Inmaculada Mena Dr. Miguel A. Casado Dr. Víctor Polo Dr. Pilar García‐Orduña Prof. Fernando J. Lahoz Prof. Luis A. Oro 《Angewandte Chemie (International ed. in English)》2014,53(36):9627-9631
In the presence of phosphanes (PR3), the amido‐bridged trinuclear complex [{Ir(μ‐NH2)(tfbb)}3] (tfbb=tetrafluorobenzobarrelene) transforms into mononuclear discrete compounds [Ir(1,2‐η2‐4‐κ‐C12H8F4N)(PR3)3], which are the products of the C? N coupling between the amido moiety and a vinylic carbon of the diolefin. An alternative synthetic approach to these species involves the reaction of the 18 e? complex [Ir(Cl)(tfbb)(PMePh2)2] with gaseous ammonia and additional phosphane. DFT studies show that both transformations occur through nucleophilic attack. In the first case the amido moiety attacks a diolefin coordinated to a neighboring molecule following a bimolecular mechanism induced by the highly basic NH2 moiety; the second pathway involves a direct nucleophilic attack of ammonia to a coordinated tfbb molecule. 相似文献
9.
Oxidative CH Bond Functionalization and Ring Expansion with TMSCHN2: A Copper(I)‐Catalyzed Approach to Dibenzoxepines and Dibenzoazepines 下载免费PDF全文
Tobias Stopka Leyre Marzo Mercedes Zurro Dr. Simon Janich Prof. Ernst‐Ulrich Würthwein Dr. Constantin G. Daniliuc Dr. José Alemán Prof. Olga García Mancheño 《Angewandte Chemie (International ed. in English)》2015,54(17):5049-5053
Tricyclic dibenzoxepines and dibenzazepines are important therapeutic agents for the pharmaceutical industry and academic research. However, their syntheses are generally rather tedious, requiring several steps that involve a Wagner–Meerwein‐type rearrangement under harsh conditions. Herein, we present the first copper(I)‐catalyzed oxidative C? H bond functionalization and ring expansion with TMSCHN2 to yield these important derivatives in a facile and straightforward way. 相似文献
10.
Copper‐Catalyzed Aerobic Oxidative Inert CC and CN Bond Cleavage: A New Strategy for the Synthesis of Tertiary Amides 下载免费PDF全文
Xiuling Chen Dr. Tieqiao Chen Qiang Li Dr. Yongbo Zhou Prof. Li‐Biao Han Prof. Shuang‐Feng Yin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(38):12234-12238
A copper‐catalyzed aerobic oxidative amidation reaction of inert C?C bonds with tertiary amines has been developed for the synthesis of tertiary amides, which are significant units in many natural products, pharmaceuticals, and fine chemicals. This method combines C?C bond activation, C?N bond cleavage, and C?H bond oxygenation in a one‐pot protocol, using molecular oxygen as the sole oxidant without any additional ligands. 相似文献
11.
Unexpected Cyclization of Tritylamines Promoted by Copper Salt through CH and CN Bond Cleavages to Produce Acridine Derivatives 下载免费PDF全文
Ryosuke Morioka Dr. Koji Hirano Prof. Dr. Tetsuya Satoh Prof. Dr. Masahiro Miura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(40):12720-12724
Herein, we demonstrate that tritylamines undergo an unprecedented copper‐mediated cyclization involving the cleavages of two C?H bonds and one C?N bond to give 9‐arylacridine derivatives. This kind of acridines is of interest due to their biological properties and their unique optical and electro‐ and photochemical properties. Some of obtained acridine derivatives exhibit intense fluorescence in the solid state. 相似文献
12.
Cobalt(III)‐Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by CH and NOH Activation 下载免费PDF全文
Malay Sen Deepti Kalsi Prof. Dr. Basker Sundararaju 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15529-15533
Efficient, scalable cobalt‐catalyzed redox‐neutral [4+2] annulation of readily available oximes and alkyne is reported. The developed synthetic methodology is widely applicable and tolerates various functional groups including heterocycles. A stable Cp*CoIII neutral complex is employed as the catalyst for this redox‐neutral [4+2] annulation reaction, which progresses smoothly by way of a reversible cyclometallation without any external oxidizing agent, and produces only water as the side product. 相似文献
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A concise and facile method for the synthesis of heterocyclic compounds with N? O tether was introduced. The two important steps of the synthesis are a Mitsunobu reaction and C? H activation. The Mitsunobu protocol allows to form the N? O moiety in the molecule, while subsequent C? H activation leads to heterocycles. 相似文献
16.
Palladium‐Catalyzed Synthesis of Phenanthridine/Benzoxazine‐Fused Quinazolinones by Intramolecular CH Bond Activation 下载免费PDF全文
Puneet K. Gupta Nisha Yadav Subodh Jaiswal Mohd. Asad Dr. Ruchir Kant Dr. Kanchan Hajela 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(38):13210-13215
A highly efficient synthesis of phenanthridine/benzoxazine‐fused quinazolinones by ligand‐free palladium‐catalyzed intramolecular C?H bond activation under mild conditions has been developed. The C?C coupling provides the corresponding N‐fused polycyclic heterocycles in good to excellent yields and with wide functional group tolerance. 相似文献
17.
Density Functional Theory Calculations on Oxidative CC Bond Cleavage and NO Bond Formation of [RuII(bpy)2(diamine)]2+ via Reactive Ruthenium Imide Intermediates 下载免费PDF全文
Dr. Xiangguo Guan Siu‐Man Law Chun‐Wai Tse Dr. Jie‐Sheng Huang Prof. Dr. Chi‐Ming Che 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):15122-15130
DFT calculations are performed on [RuII(bpy)2(tmen)]2+ ( M1 , tmen=2,3‐dimethyl‐2,3‐butanediamine) and [RuII(bpy)2(heda)]2+ ( M2 , heda=2,5‐dimethyl‐2,5‐hexanediamine), and on the oxidation reactions of M1 to give the C?C bond cleavage product [RuII(bpy)2(NH=CMe2)2]2+ ( M3 ) and the N?O bond formation product [RuII(bpy)2(ONCMe2CMe2NO)]2+ ( M4 ). The calculated geometrical parameters and oxidation potentials are in good agreement with the experimental data. As revealed by the DFT calculations, [RuII(bpy)2(tmen)]2+ ( M1 ) can undergo oxidative deprotonation to generate Ru‐bis(imide) [Ru(bpy)2(tmen‐4 H)]+ ( A ) or Ru‐imide/amide [Ru(bpy)2(tmen‐3 H)]2+ ( A′ ) intermediates. Both A and A′ are prone to C?C bond cleavage, with low reaction barriers (ΔG≠) of 6.8 and 2.9 kcal mol?1 for their doublet spin states 2 A and 2 A′ , respectively. The calculated reaction barrier for the nucleophilic attack of water molecules on 2 A′ is relatively high (14.2 kcal mol?1). These calculation results are in agreement with the formation of the RuII‐bis(imine) complex M3 from the electrochemical oxidation of M1 in aqueous solution. The oxidation of M1 with CeIV in aqueous solution to afford the RuII‐dinitrosoalkane complex M4 is proposed to proceed by attack of the cerium oxidant on the ruthenium imide intermediate. The findings of ESI‐MS experiments are consistent with the generation of a ruthenium imide intermediate in the course of the oxidation. 相似文献
18.
Hui Yu Guoying Zhang Prof. Dr. Hanmin Huang 《Angewandte Chemie (International ed. in English)》2015,54(37):10912-10916
A fundamentally novel approach to bioactive quinolizinones is based on the palladium‐catalyzed intramolecular cyclocarbonylation of allylamines. [Pd(Xantphos)I2], which features a very large bite angle, has been found to facilitate the rapid carbonylation of azaarene‐substituted allylamines into bioactive quinolizinones in good to excellent yields. This transformation represents the first dearomative carbonylation and is proposed to proceed by palladium‐catalyzed C? N bond activation, dearomatization, CO insertion, and a Heck reaction. 相似文献
19.
Palladium‐Catalyzed Intramolecular CH Difluoroalkylation: Synthesis of Substituted 3,3‐Difluoro‐2‐oxindoles 下载免费PDF全文
Dr. Shi‐Liang Shi Prof. Dr. Stephen L. Buchwald 《Angewandte Chemie (International ed. in English)》2015,54(5):1646-1650
The synthesis of 3,3‐difluoro‐2‐oxindoles through a robust and efficient palladium‐catalyzed C? H difluoroalkylation is described. This process generates a broad range of difluorooxindoles from readily prepared starting materials. The use of BrettPhos as the ligand was crucial for high efficiency. Preliminary mechanistic studies suggest that oxidative addition is the rate‐determining step for this process. 相似文献
20.
A [4+1] Cyclative Capture Approach to 3H‐Indole‐N‐oxides at Room Temperature by Rhodium(III)‐Catalyzed CH Activation 下载免费PDF全文
Dr. Yaxi Yang Xuan Wang Dr. Yuanchao Li Dr. Bing Zhou 《Angewandte Chemie (International ed. in English)》2015,54(51):15400-15404
The rhodium(III)‐catalyzed [3+2] C? H cyclization of aniline derivatives and internal alkynes represents a useful contribution to straightforward synthesis of indoles. However, there is no report on the more challenging synthesis of pharmaceutically important N‐hydroxyindoles and 3H‐indole‐N‐oxides. Reported herein is the first rhodium(III)‐catalyzed [4+1] C? H oxidative cyclization of nitrones with diazo compounds to access 3H‐indole‐N‐oxides. More significantly, this reaction proceeds at room temperature and has been extended to the synthesis of N‐hydroxyindoles and N‐hydroxyindolines. 相似文献