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1.
Carbaborane‐Substituted 1,2,3‐Triphospholanes and 1‐Aza‐2,5‐diphospholane: New Synthetic Approaches
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Dr. Anika Kreienbrink Sarah Heinicke Thi Thuy Duong Pham Dr. René Frank Dr. Peter Lönnecke Prof. Dr. Evamarie Hey‐Hawkins 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(5):1434-1439
New phosphorus‐containing, five‐membered P,P,P and P,N,P heterocycles were synthesized and fully characterized. The P,P,P heterocycles, 1,2,3‐triphospholanes, can be synthesized by two different facile pathways, whereas the P,N,P compound, a 1‐aza‐2,5‐diphospholane, can only be obtained with silylamine. 相似文献
2.
Hongyin Gao Qing‐Long Xu Muhammed Yousufuddin Daniel H. Ess Lszl Kürti 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(10):2739-2743
We disclose an efficient and operationally simple protocol for the preparation of fused N‐heterocycles starting from readily available 2‐nitrobiaryls and PhMgBr under mild conditions. More than two dozen N‐heterocycles, including two bioactive natural products, have been synthesized using this method. A stepwise electrophilic aromatic cyclization mechanism was proposed by DFT calculations. 相似文献
3.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(8):2067-2071
One‐pot cascade annulations among nitrosoarenes, alkenes, and N‐hydroxyallylamines have been achieved with CuCl/O2 catalysts, forming fused oxazinane/isoxazolidine heterocycles with excellent diastereoselectivity (d.r. >20:1). To enhance the synthetic utility, we developed a successive cleavage of the two N−O bonds of the resulting heterocycles. A mechanism involving dipolar [3+2] cycloadditions of nitrone intermediates with their tethered alkenes is postulated for formation of these heterocycles. 相似文献
4.
《Angewandte Chemie (International ed. in English)》2017,56(8):2035-2039
One‐pot cascade annulations among nitrosoarenes, alkenes, and N‐hydroxyallylamines have been achieved with CuCl/O2 catalysts, forming fused oxazinane/isoxazolidine heterocycles with excellent diastereoselectivity (d.r. >20:1). To enhance the synthetic utility, we developed a successive cleavage of the two N−O bonds of the resulting heterocycles. A mechanism involving dipolar [3+2] cycloadditions of nitrone intermediates with their tethered alkenes is postulated for formation of these heterocycles. 相似文献
5.
Prof. Dr. Suning Wang Deng‐Tao Yang Jiasheng Lu Hiroyuki Shimogawa Prof. Dr. Shaolong Gong Xiang Wang Soren K. Mellerup Prof. Dr. Atsushi Wakamiya Dr. Yi‐Lu Chang Prof. Dr. Chuluo Yang Prof. Dr. Zheng‐Hong Lu 《Angewandte Chemie (International ed. in English)》2015,54(50):15074-15078
New BN‐heterocyclic compounds have been found to undergo double arene photoelimination, forming rare yellow fluorescent BN‐pyrenes that contain two B? N units. Most significant is the discovery that the double arene elimination can also be driven by excitons generated electrically within electroluminescent (EL) devices, enabling the in situ solid‐state conversion of BN‐heterocycles to BN‐pyrenes and the use of BN‐pyrenes as emitters for EL devices. The in situ exciton‐driven elimination (EDE) phenomenon has also been observed for other BN‐heterocycles. 相似文献
6.
Mannepalli Lakshmi Kantam Gopaladasu Tirupati Venkanna Kota Balaji Shiva Kumar Vura Bala Subrahmanyam 《Helvetica chimica acta》2010,93(5):974-979
N‐Arylation of N‐containing heterocycles, such as pyrazoles, imidazoles, and benzimidazoles with aryl‐, heteroaryl‐, and vinylboronic acids was efficiently carried out by copper fluorapatite (CuFAP) catalyst in MeOH at room temperature under base‐free conditions. The N‐arylated heterocycles were isolated in good‐to‐excellent yields. 相似文献
7.
Regioselective Synthesis of N‐Heteroaromatic Trifluoromethoxy Compounds by Direct O−CF3 Bond Formation
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Apeng Liang Shuaijun Han Zhenwei Liu Liang Wang Dr. Jingya Li Prof.Dr. Dapeng Zou Prof. Dr. Yangjie Wu Prof. Dr. Yusheng Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(15):5102-5106
The first one‐step method for the synthesis of ortho‐N‐heteroaromatic trifluoromethoxy derivatives by site‐specific O?CF3 bond formation using hydroxylated N‐heterocycles and Togni's reagent is described. The approach enables the unprecedented syntheses of a wide range of six or five‐membered N‐heteroaromatic trifluoromethoxy compounds containing one or two heteroatoms from most commonly used hydroxylated N‐heterocycles. Notable advantages of this method include its simplicity and mild conditions, avoidance of the need for metals or toxic reagents, and compatibility with a variety of functional groups. Furthermore, this method is especially suitable for the larger scale application. 相似文献
8.
Metal‐Free Dehydrogenation of N‐Heterocycles by Ternary h‐BCN Nanosheets with Visible Light
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Dr. Meifang Zheng Jiale Shi Tao Yuan Prof. Xinchen Wang 《Angewandte Chemie (International ed. in English)》2018,57(19):5487-5491
An efficient metal‐free catalytic system has been developed based on hexagonal boron carbon nitride (h‐BCN) nanosheets for the dehydrogenation of N‐heterocycles with visible light; hydrogen gas is released in the process, and thus no proton acceptor is needed. This acceptorless dehydrogenation of hydroquinolines, hydroisoquinolines, and indolines to the corresponding aromatic N‐heterocycles occurred in excellent yield under visible‐light irradiation at ambient temperature. With h‐BCN as the photocatalyst and water as the solvent, this environmentally benign protocol shows broad substitution tolerance and high efficiency. 相似文献
9.
V. Surendra Babu Damerla Chiranjeevi Tulluri Dr. Rambabu Gundla Lava Naviri Prof. Uma Adepally Pravin S. Iyer Prof. Y. L. N. Murthy Nampally Prabhakar Dr. Subhabrata Sen 《化学:亚洲杂志》2012,7(10):2351-2360
Herein, we report a diversity‐oriented‐synthesis (DOS) approach for the synthesis of biologically relevant molecular scaffolds. Our methodology enables the facile synthesis of fused N‐heterocycles, spirooxoindolones, tetrahydroquinolines, and fused N‐heterocycles. The two‐step sequence starts with a chiral‐bicyclic‐lactam‐directed enolate‐addition/substitution step. This step is followed by a ring‐closure onto the built‐in scaffold electrophile, thereby leading to stereoselective carbocycle‐ and spirocycle‐formation. We used in silico tools to calibrate our compounds with respect to chemical diversity and selected drug‐like properties. We evaluated the biological significance of our scaffolds by screening them in two cancer cell‐lines. In summary, our DOS methodology affords new, diverse scaffolds, thereby resulting in compounds that may have significance in medicinal chemistry. 相似文献
10.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(11):2973-2977
The first catalytic formal [5+4] cycloaddition to prepare nine‐membered heterocycles is presented. Under palladium catalysis, the reaction of N‐tosyl azadienes and substituted vinylethylene carbonates (VECs) proceeds smoothly to produce benzofuran‐fused heterocycles in uniformly high efficiency. Highly diastereoselective functionalization of the nine‐membered heterocycles through peripheral attack is also demonstrated. 相似文献
11.
Experimental and Computational Study of the Catalytic Asymmetric 4π‐Electrocyclization of N‐Heterocycles
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Dr. Sadiya Raja Dr. Masaki Nakajima Prof. Dr. Magnus Rueping 《Angewandte Chemie (International ed. in English)》2015,54(9):2762-2765
The first asymmetric metal‐catalyzed Nazarov cyclization of N‐heterocycles has been developed. The use of a chiral catalyst allows the enantioselective electrocyclization of N‐heterocycles under mild conditions and the corresponding products are obtained in good yields with excellent enantio‐ and diastereoselectivity. The reaction mechanism and the absolute configuration of the obtained products are explained by means of computational studies. 相似文献
12.
Highly Enantioselective Nucleophilic Dearomatization of Pyridines by Anion‐Binding Catalysis
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Prof. Dr. Olga García Mancheño Sören Asmus Mercedes Zurro Theresa Fischer 《Angewandte Chemie (International ed. in English)》2015,54(30):8823-8827
The asymmetric dearomatization of N‐heterocycles is an important synthetic method to gain bioactive and synthetically valuable chiral heterocycles. However, the catalytic enantio‐ and regioselective dearomatization of the simplest six‐membered‐ring N‐heteroarenes, the pyridines, is still very challenging. The first anion‐binding‐catalyzed, highly enantioselective nucleophilic dearomatization of pyridines with triazole‐based H‐bond donor catalysts is presented. Contrary to other more common NH‐based H‐bond donors, this type of organocatalyst shows a prominent higher C2‐regioselectivity and is able to promote high enantioinductions via formation of a close chiral anion‐pair complex with a preformed N‐acyl pyridinium ionic intermediate. This method offers a straightforward and useful synthetic approach to chiral N‐heterocycles from abundant and readily available pyridines. 相似文献
13.
Palladium‐Catalyzed Carbonylative Reactions of 1‐Bromo‐2‐fluorobenzenes with Various Nucleophiles: Effective Combination of Carbonylation and Nucleophilic Substitution
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Jianbin Chen Dr. Kishore Natte Dr. Helfried Neumann Prof. Xiao‐Feng Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(49):16107-16110
A systematic study on the carbonylative transformation of 1‐bromo‐2‐fluorobenzenes with various nucleophiles has been performed. Different types of double nucleophiles, such as N?N, N?C, O?C, and N?S, can be effectively applied as coupling partners. The corresponding six‐membered heterocycles were isolated in moderate to good yields. 相似文献
14.
Thermal and Photolytic Transformation of NHC–B,N‐Heterocycles: Controlled Generation of Blue Fluorescent 1,3‐Azaborinine Derivatives and 1H‐Imidazo[1,2‐a]indoles by External Stimuli
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Sean M. McDonald Soren K. Mellerup Dr. Jinbao Peng Dengtao Yang Prof. Dr. Quan‐Song Li Prof. Dr. Suning Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(40):13961-13970
NHC–B,N‐heterocyclic compounds have been found to act as convenient precursors for obtaining either 1,3‐azaborinine or 1H‐imidazo[1,2‐a]indole derivatives, which are two different and rare classes of compounds. The formation of these two classes of compounds from the NHC–B,N‐heterocycles is highly selective depending on the external stimuli employed, and the resulting products have been studied for their interesting chemical and photophysical properties. The mechanism and possible reaction pathways of the unusual transformation are established by computational studies. 相似文献
15.
Hypervalent‐Iodine‐Mediated Cascade Annulation of Diarylalkynes Forming Spiro Heterocycles under Metal‐Free Conditions
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Xiang Zhang Chao Yang Prof. Dr. Daisy Zhang‐Negrerie Prof. Dr. Yunfei Du 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(13):5193-5198
An unusual reaction featuring the cascade annulation of internal alkynes to afford spiro heterocycles as the products has been realized for the first time with a hypervalent iodine reagent as the only oxidant. This unprecedented process encompasses not only two sequential C?N/C?O‐bond formations, but also the insertion of a carbonyl oxygen, all in one pot under metal‐free conditions. 相似文献
16.
Palladium‐Catalyzed Multi‐Component Reactions of N‐Tosylhydrazones, 2‐Iodoanilines and CO2 towards 4‐Aryl‐2‐Quinolinones
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Dr. Song Sun Wei‐Ming Hu Ning Gu Prof. Dr. Jiang Cheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(52):18729-18732
A palladium‐catalyzed three‐component reaction between N‐tosylhydrazones, 2‐iodoanilines and atmospheric pressure CO2 was developed whereby a tandem carbene migration insertion/lactamization strategy afforded 4‐aryl‐2‐quinolinones in moderate to good yields. Notably, a wide range of functional groups were tolerated in this procedure. This protocol features the simultaneous formation of four novel bonds; two C?C, one C=C and one C?N (amide), representing an efficient methodology for incorporation of CO2 into heterocycles. 相似文献
17.
Dinesh Talwar Angela Gonzalez‐de‐Castro Ho Yin Li Jianliang Xiao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(17):5312-5316
A new strategy has been developed for the oxidant‐ and base‐free dehydrogenative coupling of N‐heterocycles at mild conditions. Under the action of an iridium catalyst, N‐heterocycles undergo multiple sp3 C H activation steps, generating a nucleophilic enamine that reacts in situ with various electrophiles to give highly functionalized products. The dehydrogenative coupling can be cascaded with Friedel–Crafts addition, resulting in a double functionalization of the N‐heterocycles. 相似文献
18.
Metal‐Free Hydrogen Atom Transfer from Water: Expeditious Hydrogenation of N‐Heterocycles Mediated by Diboronic Acid
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Yun‐Tao Xia Xiao‐Tao Sun Ling Zhang Kai Luo Prof. Dr. Lei Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17151-17155
A hydrogenation of N‐heterocycles mediated by diboronic acid with water as the hydrogen atom source is reported. A variety of N‐heterocycles can be hydrogenated with medium to excellent yields within 10 min. Complete deuterium incorporation from stoichiometric D2O onto substrates further exemplifies the H/D atom sources. Mechanism studies reveal that the reduction proceeds with initial 1,2‐addition, in which diboronic acid synergistically activates substrates and water via a six‐membered ring transition state. 相似文献
19.
P. Marchenko Anatoliy K. Koydan Georgiy S. Huryeva Anastasia V. Smaliy Radomyr A. Yurchenko Aleksandr N. Alekseenko Anatoliy 《Heteroatom Chemistry》2010,21(7):453-455
It has been found that N‐(4‐imidazolyl)phosphinimidic isocyanates obtained by the reaction of the corresponding chlorophosphine N‐hetarylimide with alkali metal cyanates can undergo intramolecular heterocyclization to yield previously unknown phosphapurine derivatives containing an endocyclic PN double bond. This radically novel approach to building the 2‐phosphapurine system shows promise for the synthesis of related phosphorus‐containing fused heterocycles. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:453–455, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20617 相似文献
20.
Regioselective Acceptorless Dehydrogenative Coupling of N‐Heterocycles toward Functionalized Quinolines,Phenanthrolines, and Indoles
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Dinesh Talwar Angela Gonzalez‐de‐Castro Dr. Ho Yin Li Prof. Jianliang Xiao 《Angewandte Chemie (International ed. in English)》2015,54(17):5223-5227
A new strategy has been developed for the oxidant‐ and base‐free dehydrogenative coupling of N‐heterocycles at mild conditions. Under the action of an iridium catalyst, N‐heterocycles undergo multiple sp3 C? H activation steps, generating a nucleophilic enamine that reacts in situ with various electrophiles to give highly functionalized products. The dehydrogenative coupling can be cascaded with Friedel–Crafts addition, resulting in a double functionalization of the N‐heterocycles. 相似文献