共查询到20条相似文献,搜索用时 15 毫秒
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Ming Zhang 《应用有机金属化学》2010,24(4):269-284
The C? H functionalization strategy has received substantial attention because of its economic, sustainable and environmentally benign features. Most reports are on palladium, rhodium or ruthenium catalysis, and reports on copper catalysis are relatively fewer. Recently, many reports on copper‐catalyzed/mediated C? H functionalization have been published. Copper salts bear properties of cheapness and relatively low toxicity. This review introduces an advance on copper‐catalyzed/mediated aromatic C? H functionalization. The content includes aromatic ring C? H bond functionalization and heteroaromatic C? H bond functionalization forming new carbon–carbon or carbon–heteroatom bonds. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Manganese‐Catalyzed Dehydrogenative [4+2] Annulation of N?H Imines and Alkynes by C?H/N?H Activation
Ruoyu He Zhi‐Tang Huang Qi‐Yu Zheng Congyang Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(19):5050-5053
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
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Sarah E. Walker James A. Jordan‐Hore David G. Johnson Stuart A. Macgregor Ai‐Lan Lee 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(50):14096-14099
A direct Pd‐catalyzed C H functionalization of benzoquinone (BQ) can be controlled to give either mono‐ or disubstituted BQ, including the installation of two different groups in a one‐pot procedure. BQ can now be directly functionalized with aryl, heteroaryl, cycloalkyl, and cycloalkene groups and, moreover, the reaction is conducted in environmentally benign water or acetone as solvents. 相似文献
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Dr. Natarajan Senthilkumar Dr. Kanniyappan Parthasarathy Dr. Parthasarathy Gandeepan Prof. Dr. Chien‐Hong Cheng 《化学:亚洲杂志》2013,8(9):2175-2181
An efficient method for the one‐pot synthesis of substituted phenanthridinone derivatives from N‐methoxybenzamides and aryltriethoxysilanes through rhodium‐catalyzed dual C? H bond activation and annulation reactions is described. A double‐cycle mechanism is proposed to account for this catalytic reaction. In addition, isotope‐labeling studies were performed to understand the intimate mechanism of the reaction. 相似文献
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Elizabeth A. Jacobs Anna Fuller Simon J. Coles Graham J. Tizzard Joseph A. Wright Simon J. Lancaster 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(28):8647-8658
Treatment of Me2S ? B(C6F5)nH3?n (n=1 or 2) with ammonia yields the corresponding adducts. H3N ? B(C6F5)H2 dimerises in the solid state through N? H???H? B dihydrogen interactions. The adducts can be deprotonated to give lithium amidoboranes Li[NH2B(C6F5)nH3?n]. Reaction of the n=2 reagent with [Cp2ZrCl2] leads to disubstitution, but [Cp2Zr{NH2B(C6F5)2H}2] is in equilibrium with the product of β‐hydride elimination [Cp2Zr(H){NH2B(C6F5)2H}], which proves to be the major isolated solid. The analogous reaction with [Cp2HfCl2] gives a mixture of [Cp2Hf{NH2B(C6F5)2H}2] and the N? H activation product [Cp2Hf{NHB(C6F5)2H}]. [Cp2Zr{NH2B(C6F5)2H}2] ? PhMe and [Cp2Hf{NH2B(C6F5)2H}2] ? 4(thf) exhibit β‐B‐agostic chelate bonding of one of the two amidoborane ligands in the solid state. The agostic hydride is invariably coordinated to the outside of the metallocene wedge. Exceptionally, [Cp2Hf{NH2B(C6F5)2H}2] ? PhMe has a structure in which the two amidoborane ligands adopt an intermediate coordination mode, in which neither is definitively agostic. [Cp2Hf{NHB(C6F5)2H}] has a formally dianionic imidoborane ligand chelating through an agostic interaction, but the bond‐length distribution suggests a contribution from a zwitterionic amidoborane resonance structure. Treatment of the zwitterions [Cp2MMe(μ‐Me)B(C6F5)3] (M=Zr, Hf) with Li[NH2B(C6F5)nH3?n] (n=2) results in [Cp2MMe{NH2B(C6F5)2H}] complexes, for which the spectroscopic data, particularly 1J(B,H), again suggest β‐B‐agostic interactions. The reactions proceed similarly for the structurally encumbered [Cp′′2ZrMe(μ‐Me)B(C6F5)3] precursor (Cp′′=1,3‐C5H3(SiMe3)2, n=1 or 2) to give [Cp′′2ZrMe{NH2B(C6F5)nH3?n}], both of which have been structurally characterised and show chelating, agostic amidoborane coordination. In contrast, the analogous hafnium chemistry leads to the recovery of [Cp′′2HfMe2] and the formation of Li[HB(C6F5)3] through hydride abstraction. 相似文献
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Yong‐Jun Bian Chao‐Yue Chen Prof. Zhi‐Zhen Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(3):1129-1133
An efficient palladium‐catalyzed C? H functionalization of aldehydes with various N‐substituted N‐heteroarene‐2‐carboxamides has been developed for the synthesis of secondary imides. The reaction tolerates various functionalities, such as methoxy, fluoro, chloro, and bromo groups. A tentative radical mechanism for a PdII/PdIV catalytic cycle is proposed. 相似文献
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Joyce Wei Wei Chang Thi My Uyen Ton Philip Wai Hong Chan 《Chemical record (New York, N.Y.)》2011,11(6):331-357
Catalytic insertion or addition of a metal‐imido/nitrene species, generated from reaction of a transition‐metal catalyst with iminoiodanes, to C? H and C?C bonds offers a convenient and atom economical method for the synthesis of nitrogen‐containing compounds. Following this groundbreaking discovery during the second half of the last century, the field has received an immense amount of attention with a myriad of impressive metal‐mediated methods for the synthesis of amines and aziridines having been developed. This review will cover the significant progress made in improving the efficiency, versatility and stereocontrol of this important reaction. This will include the various iminoiodanes, their in situ formation, and metal catalysts that could be employed and new ligands, both chiral and non‐chiral, which have been designed, as well as the application of this functional group transformation to natural product synthesis and the preparation of bioactive compounds of current therapeutic interest. DOI 10.1002/tcr.201100018 相似文献