共查询到20条相似文献,搜索用时 15 毫秒
1.
Dr. Rajavel Srinivasan Dr. Anthony G. Coyne Prof. Dr. Chris Abell 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(37):11680-11684
A one‐pot protocol for the synthesis of N‐aryl 1,2,3‐triazoles from arenes by an iridium‐catalyzed C?H borylation/copper catalyzed azidation/click sequence is described. 1 mol % of Cu(OTf)2 was found to efficiently catalyze both the azidation and the click reaction. The applicability of this method is demonstrated by the late‐stage chemoselective installation of 1,2,3‐triazole moiety into unactivated molecules of pharmaceutical importance. 相似文献
2.
Rhodium(III)‐Catalyzed Alkenylation Reactions of 8‐Methylquinolines with Alkynes by C(sp3)H Activation 下载免费PDF全文
Bingxian Liu Tao Zhou Prof. Dr. Bin Li Prof. Shansheng Xu Prof. Dr. Haibin Song Prof. Dr. Baiquan Wang 《Angewandte Chemie (International ed. in English)》2014,53(16):4191-4195
The alkenylation reactions of 8‐methylquinolines with alkynes, catalyzed by [{Cp*RhCl2}2], proceeds efficiently to give 8‐allylquinolines in good yields by C(sp3)? H bond activation. These reactions are highly regio‐ and stereoselective. A catalytically competent five‐membered rhodacycle has been structurally characterized, thus revealing a key intermediate in the catalytic cycle. 相似文献
3.
Boryl (Hetero)aryne Precursors as Versatile Arylation Reagents: Synthesis through CH Activation and Orthogonal Reactivity 下载免费PDF全文
Dr. Emilien Demory Karthik Devaraj Dr. Andreas Orthaber Dr. Paul J. Gates Dr. Lukasz T. Pilarski 《Angewandte Chemie (International ed. in English)》2015,54(40):11765-11769
(Pinacolato)boryl ortho‐silyl(hetero)aryl triflates are presented as a new class of building blocks for arylation. They demonstrate unique versatility by delivering boronate or (hetero)aryne reactivity chemoselectively in a broad range of transformations. This approach enables the unprecedented postfunctionalization of fluoride‐activated (hetero)aryne precursors, for example, as substrates in transition‐metal catalysis, and offers valuable new possibilities for aryl boronate postfunctionalization without the use of specialized protecting groups. 相似文献
4.
Rhodium(I)‐Catalyzed Regiospecific Dimerization of Aromatic Acids: Two Direct CH Bond Activations in Water 下载免费PDF全文
Dr. Hang Gong Dr. Huiying Zeng Dr. Feng Zhou Prof. Dr. Chao‐Jun Li 《Angewandte Chemie (International ed. in English)》2015,54(19):5718-5721
2,2′‐Diaryl acids are key building blocks for some of the most important and high‐performance polymers such as polyesters and polyamides (imides), as well as structural motifs of MOFs (metal–organic frameworks) and biological compounds. In this study, a direct, regiospecific and practical dimerization of simple aromatic acids to generate 2,2′‐diaryl acids has been discovered, which proceeds through two rhodium‐catalyzed C? H activations in water. This reaction can be easily scaled up to gram level by using only 0.4–0.6 mol % of the rhodium catalyst. As a proof‐of‐concept, the natural product ellagic acid was synthesized in two steps by this method. 相似文献
5.
Diaryliodoniums by Rhodium(III)‐Catalyzed CH Activation: Mild Synthesis and Diversified Functionalizations 下载免费PDF全文
Dr. Fang Xie Zhipeng Zhang Dr. Xinzhang Yu Guodong Tang Prof. Dr. Xingwei Li 《Angewandte Chemie (International ed. in English)》2015,54(25):7405-7409
Diaryliodonium salts play an increasingly important role as an aryl source. Reported is the first synthesis of diaryliodoniums by rhodium(III)‐catalyzed C? H hyperiodination of electron‐poor arenes under chelation assistance. This C? I coupling reaction occurred at room temperature with high regio‐selectivity and functional‐group compatibility. Subsequent diversified nucleophilic functionalization of a diaryliodonium allowed facile construction of C? C, C? N, C? O, C? S, C? P and C? Br bonds, and in all cases the initial functionalization occurred at the arene containing the chelating‐group. 相似文献
6.
Palladium(II)‐Catalyzed meta‐CH Olefination: Constructing Multisubstituted Arenes through Homo‐Diolefination and Sequential Hetero‐Diolefination 下载免费PDF全文
Dr. Milan Bera Arun Maji Dr. Santosh K. Sahoo Prof. Debabrata Maiti 《Angewandte Chemie (International ed. in English)》2015,54(29):8515-8519
Divinylbenzene derivatives represent an important class of molecular building blocks in organic chemistry and materials science. Reported herein is the palladium‐catalyzed synthesis of divinylbenzenes by meta‐C? H olefination of sulfone‐based arenes. Successful sequential olefinations in a position‐selective manner provided a novel route for the synthesis of hetero‐dialkenylated products, which are difficult to access using conventional methods. Additionally, 1,3,5‐trialkenylated compounds can be generated upon successful removal of the directing group. 相似文献
7.
Rhodium(III)‐Catalyzed Transannulation of Cyclopropenes with N‐Phenoxyacetamides through CH Activation 下载免费PDF全文
Hang Zhang Kang Wang Bo Wang Heng Yi Fangdong Hu Dr. Changkun Li Dr. Yan Zhang Prof. Dr. Jianbo Wang 《Angewandte Chemie (International ed. in English)》2014,53(48):13234-13238
An efficient rhodium(III)‐catalyzed synthesis of 2H‐chromene from N‐phenoxyacetamides and cyclopropenes has been developed. The reaction represents the first example of using cyclopropenes as a three‐carbon unit in rhodium(III)‐catalyzed C(sp2)? H activations. 相似文献
8.
Room‐Temperature ortho‐Alkoxylation and ‐Halogenation of N‐Tosylbenzamides by Using Palladium(II)‐Catalyzed CH Activation 下载免费PDF全文
Dr. Florent Péron Dr. Christine Fossey Prof. Dr. Jana Sopkova‐de Oliveira Santos Dr. Thomas Cailly Prof. Dr. Frédéric Fabis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(24):7507-7513
The N‐tosylcarboxamide group can direct the room‐temperature palladium‐catalyzed C?H alkoxylation and halogenation of substituted arenes in a simple and mild procedure. The room‐temperature stoichiometric cyclopalladation of N‐tosylbenzamide was first studied, and the ability of the palladacycle to react with oxidants to form C?X and C?O bonds under mild conditions was demonstrated. The reaction conditions were then adapted to promote room‐temperature ortho‐alkoxylations and ortho‐halogenations of N‐tosylbenzamides using palladium as catalyst. The scope and limitation of both alkoxylations and halogenations was studied and the subsequent functional transformation of the N‐tosylcarboxamide group through nucleophilic additions was evaluated. This methodology offers a simple and mild route to diversely functionalized arenes. 相似文献
9.
Fen Wang Xinzhang Yu Zisong Qi Prof. Dr. Xingwei Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(2):511-516
Rhodium‐catalyzed sulfonylation, thioetherification, thiocyanation, and other heterofunctionalizations of arenes bearing a heterocyclic directing group have been realized. The reaction proceeds by initial RhIII‐catalyzed C?H hyperiodination of arene at room temperature followed by uncatalyzed nucleophilic functionalization. A diaryliodonium salt is isolated as an intermediate, which represents umpolung of the arene substrate, in contrast to previous studies that suggested umpolung of the coupling partner. 相似文献
10.
Rhodium(III)‐Catalyzed CC and CO Coupling of Quinoline N‐Oxides with Alkynes: Combination of CH Activation with O‐Atom Transfer 下载免费PDF全文
Xueyun Zhang Zisong Qi Prof. Xingwei Li 《Angewandte Chemie (International ed. in English)》2014,53(40):10794-10798
[Cp*RhIII]‐catalyzed C? H activation of arenes assisted by an oxidizing N? O or N? N directing group has allowed the construction of a number of hetercycles. In contrast, a polar N? O bond is well‐known to undergo O‐atom transfer (OAT) to alkynes. Despite the liability of N? O bonds in both C? H activation and OAT, these two important areas evolved separately. In this report, [Cp*RhIII] catalysts integrate both areas in an efficient redox‐neutral coupling of quinoline N‐oxides with alkynes to afford α‐(8‐quinolyl)acetophenones. In this process the N? O bond acts as both a directing group for C? H activation and as an O‐atom donor. 相似文献
11.
M. Sc. Jie Li Prof. Dr. Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2015,54(12):3635-3638
Carboxylate assistance proved to be the key for the success of efficient cobalt(III)‐catalyzed C? H cyanations. Thus, an in situ generated cationic cobalt complex was identified as a versatile catalyst for the site‐selective synthesis of various aromatic and heteroaromatic nitriles with ample substrate scope. 相似文献
12.
Rhodium(III)‐Catalyzed Selective ortho‐Olefinations of N‐Acyl and N‐Aroyl Sulfoximines by CH Bond Activation 下载免费PDF全文
Dr. Kanniyappan Parthasarathy Prof. Dr. Carsten Bolm 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(17):4896-4900
Two new rhodium‐catalyzed oxidative couplings between sulfoximine derivatives and alkenes by regioselective C?H activation, affording ortho‐olefinated (Heck‐type) products, are reported. A synthetic application of the ortho‐alkenylated products into the corresponding cyclic derivatives has been demonstrated, and a mechanistic rational for the rhodium catalysis is presented. 相似文献
13.
Rhodium(III)‐Catalyzed Three‐Component Reaction of Imines,Alkynes, and Aldehydes through CH Activation 下载免费PDF全文
Ji‐Rong Huang Qiang Song Yu‐Qin Zhu Liu Qin Prof. Dr. Zhi‐Yong Qian Prof. Dr. Lin Dong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):16882-16886
An efficient rhodium(III)‐catalyzed tandem three‐component reaction of imines, alkynes and aldehydes through C?H activation has been developed. High stereo‐ and regioselectivity, as well as good yields were obtained in most cases. The simple and atom‐economical approach offers a broad scope of substrates, providing polycyclic skeletons with potential biological properties. 相似文献
14.
One‐Pot Synthesis of Highly Substituted Polyheteroaromatic Compounds by Rhodium(III)‐Catalyzed Multiple CH Activation and Annulation 下载免费PDF全文
Jayachandran Jayakumar Dr. Kanniyappan Parthasarathy Yi‐Hsiang Chen Tai‐Hua Lee Prof. Dr. Shih‐Ching Chuang Prof. Dr. Chien‐Hong Cheng 《Angewandte Chemie (International ed. in English)》2014,53(37):9889-9892
A new method for the synthesis of highly substituted naphthyridine‐based polyheteroaromatic compounds in high yields proceeds through rhodium(III)‐catalyzed multiple C? H bond cleavage and C? C and C? N bond formation in a one‐pot process. Such highly substituted polyheteroaromatic compounds have attracted much attention because of their unique π‐conjugation, which make them suitable materials for organic semiconductors and luminescent materials. Furthermore, a possible mechanism, which involves multiple chelation‐assisted ortho C? H activation, alkyne insertion, and reductive elimination, is proposed for this transformation. 相似文献
15.
Dr. Lin He Dr. Kishore Natte Dr. Jabor Rabeah Dr. Christoph Taeschler Dr. Helfried Neumann Prof. Dr. Angelika Brückner Prof. Dr. Matthias Beller 《Angewandte Chemie (International ed. in English)》2015,54(14):4320-4324
Fluorinated organic compounds are gaining increasing interest for life science applications. The replacement of hydrogen in arenes or heteroarenes by a perfluoroalkyl group has a profound influence on the physical and biological properties of such building blocks. Here, an operationally simple protocol for the direct C? H perfluoroalkylation of (hetero)arenes with RfI or RfBr has been developed, using a robust supported platinum catalyst. The ready availability of the starting materials, the excellent substrate tolerance, and the reusability of the catalyst make this method attractive for the synthesis of a variety of perfluoroalkyl‐substituted aromatic compounds. Preliminary mechanistic studies revealed the formation of radicals to be crucial in the reaction system. 相似文献
16.
Highly Enantioselective Rhodium(I)‐Catalyzed Carbonyl Carboacylations Initiated by CC Bond Activation 下载免费PDF全文
Laetitia Souillart Prof. Dr. Nicolai Cramer 《Angewandte Chemie (International ed. in English)》2014,53(36):9640-9644
The lactone motif is ubiquitous in natural products and pharmaceuticals. The Tishchenko disproportionation of two aldehydes, a carbonyl hydroacylation, is an efficient and atom‐economic access to lactones. However, these reaction types are limited to the transfer of a hydride to the accepting carbonyl group. The transfer of alkyl groups enabling the formation of C? C bonds during the ester formation would be of significant interest. Reported herein is such asymmetric carbonyl carboacylation of aldehydes and ketones, thus affording complex bicyclic lactones in excellent enantioselectivities. The rhodium(I)‐catalyzed transformation is induced by an enantiotopic C? C bond activation of a cyclobutanone and the formed rhodacyclic intermediate reacts with aldehyde or ketone groups to give highly functionalized lactones. 相似文献
17.
Exceedingly Fast Copper(II)‐Promoted ortho CH Trifluoromethylation of Arenes using TMSCF3 下载免费PDF全文
Ming Shang Shang‐Zheng Sun Dr. Hong‐Li Wang Dr. Brian N. Laforteza Prof. Dr. Hui‐Xiong Dai Prof. Dr. Jin‐Quan Yu 《Angewandte Chemie (International ed. in English)》2014,53(39):10439-10442
The direct ortho‐trifluoromethylation of arenes, including heteroarenes, with TMSCF3 has been accomplished by a copper(II)‐promoted C? H activation reaction which completes within 30 minutes. Mechanistic investigations are consistent with the involvement of C? H activation, rather than a simple electrophilic aromatic substitution (SEAr), as the key step. 相似文献
18.
Mechanistic Study on Rh‐Catalyzed Stereoselective CC/CH Activation of tert‐Cyclobutanols 下载免费PDF全文
Dr. Haizhu Yu Dr. Chen Wang Yimeng Yang Prof. Zhi‐Min Dang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(13):3839-3848
A mechanistic study was performed on the Rh‐catalyzed stereoselective C?C/C?H activation of tert‐cyclobutanols. The present study corroborated the previous proposal that the reaction occurs by metalation, β‐C elimination, 1,4‐Rh transfer, C?O insertion, and a final catalyst‐regeneration step. The rate‐determining step was found to be the 1,4‐Rh transfer step, whereas the stereoselectivity‐determining step did not correspond to any of the aforementioned steps. It was found that both the thermodynamic stability of the product of the β‐C elimination and the kinetic feasibility of the 1,4‐Rh transfer and C?O insertion steps made important contributions. In other words, three steps (i.e., β‐C elimination, 1,4‐Rh transfer, and C?O insertion) were found to be important in determining the configurations of the two quaternary stereocenters. 相似文献
19.
Chao Feng Prof. Dr. Teck‐Peng Loh 《Angewandte Chemie (International ed. in English)》2014,53(10):2722-2726
The rhodium(III)‐catalyzed ortho C? H alkynylation of non‐electronically activated arenes is disclosed. This process features a straightforward and highly effective protocol for the synthesis of functionalized alkynes and represents the first example of merging a hypervalent iodine reagent with rhodium(III) catalysis. Notably, this reaction proceeds at room temperature, tolerates a variety of functional groups, and more importantly, exhibits high selectivity for monoalkynylation. 相似文献
20.
Silver‐Catalyzed Oxidative Activation of Benzylic CH Bonds for the Synthesis of Difluoromethylated Arenes 下载免费PDF全文
Peng Xu Shuo Guo Liyan Wang Prof. Dr. Pingping Tang 《Angewandte Chemie (International ed. in English)》2014,53(23):5955-5958
A mild and catalytic method to form difluoromethylated arenes through the activation of benzylic C? H bonds has been developed. Utilizing AgNO3 as the catalyst, various arenes with diverse functional groups undergo activation/fluorination of benzylic C? H bonds with commercially available Selectfluor reagent as a source of fluorine in aqueous solution. The reaction is operationally simple and amenable to gram‐scale synthesis. 相似文献