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1.
Asymmetric Synthesis of Isoindolones by Chiral Cyclopentadienyl‐Rhodium(III)‐Catalyzed CH Functionalizations 下载免费PDF全文
Baihua Ye Prof. Dr. Nicolai Cramer 《Angewandte Chemie (International ed. in English)》2014,53(30):7896-7899
Directed Cp*RhIII‐catalyzed carbon–hydrogen (C? H) bond functionalizations have evolved as a powerful strategy for the construction of heterocycles. Despite their high value, the development of related asymmetric reactions is largely lagging behind due to a limited availability of robust and tunable chiral cyclopentadienyl ligands. Rhodium complexes comprising a chiral Cp ligand with an atropchiral biaryl backbone enables an asymmetric synthesis of isoindolones from arylhydroxamates and weakly alkyl donor/acceptor diazo derivatives as one‐carbon component under mild conditions. The complex guides the substrates with a high double facial selectivity yielding the chiral isoindolones in good yields and excellent enantioselectivities. 相似文献
2.
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
3.
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
4.
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
5.
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
6.
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
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.
Dr. Yaxi Yang Dr. Wei Hou Lihuai Qin Dr. Juanjuan Du Huijin Feng Dr. Bing Zhou Dr. Yuanchao Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):416-420
The rhodium‐catalyzed intermolecular direct C?H thiolation of arenes with aryl and alkyl disulfides was developed for the first time to provide a convenient route to aryl thioethers. This strategy is compatible with many different directing groups and exhibits excellent functional group tolerance. More significantly, mono‐ or dithiolation can be selectively achieved, thus providing a straightforward way for selective preparation of aryl thioethers and dithioethers. 相似文献
9.
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
10.
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
11.
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
12.
Hui Wang Julian Koeller Weiping Liu Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15525-15528
C?H/N?O functionalizations by cobalt(III) catalysis allowed the expedient synthesis of a broad range of isoquinolines. Thus, internal and challenging terminal alkynes proved to be viable substrates for an isohypsic annulation, which was shown to proceed by a facile C?H cobaltation. 相似文献
13.
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
14.
Carboxylic Acids as Traceless Directing Groups for the Rhodium(III)‐Catalyzed Decarboxylative CH Arylation of Thiophenes 下载免费PDF全文
Yuanfei Zhang Huaiqing Zhao Min Zhang Prof. Weiping Su 《Angewandte Chemie (International ed. in English)》2015,54(12):3817-3821
A rhodium(III)‐catalyzed carboxylic acid directed decarboxylative C? H/C? H cross‐coupling of carboxylic acids with thiophenes has been developed. With a slight adjustment of the reaction conditions based on the nature of the substrates, aryl carboxylic acids with a variety of substituents could serve as suitable coupling partners, and a broad variety of functional groups were tolerated. This method provides straightforward access to biaryl scaffolds with diverse substitution patterns, many of which have conventionally been synthesized through lengthy synthetic sequences. An illustrative example is the one‐step gram‐scale synthesis of a biologically active 3,5‐substituted 2‐arylthiophene by way of the current method. 相似文献
15.
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
16.
Highly Enantioselective Rhodium(I)‐Catalyzed Activation of Enantiotopic Cyclobutanone CC Bonds 下载免费PDF全文
Laetitia Souillart Dr. Evelyne Parker Prof. Dr. Nicolai Cramer 《Angewandte Chemie (International ed. in English)》2014,53(11):3001-3005
The selective functionalization of carbon–carbon σ bonds is a synthetic strategy that offers uncommon retrosynthetic disconnections. Despite progress in C? C activation and its great importance, the development of asymmetric reactions lags behind. Rhodium(I)‐catalyzed selective oxidative additions into enantiotopic C? C bonds in cyclobutanones are reported. Even operating at a reaction temperature of 130 °C, the process is characterized by outstanding enantioselectivity with the e.r. generally greater than 99.5:0.5. The intermediate rhodacycle is shown to react with a wide variety of tethered olefins to deliver complex bicyclic ketones in high yields. 相似文献
17.
All‐Carbon [3+3] Oxidative Annulations of 1,3‐Enynes by Rhodium(III)‐Catalyzed CH Functionalization and 1,4‐Migration 下载免费PDF全文
Dr. David J. Burns Dr. Daniel Best Dr. Martin D. Wieczysty Prof. Hon Wai Lam 《Angewandte Chemie (International ed. in English)》2015,54(34):9958-9962
1,3‐Enynes containing allylic hydrogens cis to the alkyne function as three‐carbon components in rhodium(III)‐catalyzed, all‐carbon [3+3] oxidative annulations to produce spirodialins. The proposed mechanism of these reactions involves the alkenyl‐to‐allyl 1,4‐rhodium(III) migration. 相似文献
18.
Diastereoselective Carbocyclization of 1,6‐Heptadienes Triggered by Rhodium‐Catalyzed Activation of an Olefinic CH Bond 下载免费PDF全文
Dr. Christophe Aïssa Kelvin Y. T. Ho Dr. Daniel J. Tetlow María Pin‐Nó 《Angewandte Chemie (International ed. in English)》2014,53(16):4209-4212
The use of α,ω‐dienes as functionalization reagents for olefinic carbon–hydrogen bonds has been rarely studied. Reported herein is the rhodium(I)‐catalyzed rearrangement of prochiral 1,6‐heptadienes into [2,2,1]‐cycloheptane derivatives with concomitant creation of at least three stereogenic centers and complete diastereocontrol. Deuterium‐labeling studies and the isolation of a key intermediate are consistent with a group‐directed C? H bond activation, followed by two consecutive migratory insertions, with only the latter step being diastereoselective. 相似文献
19.
α‐MsO/TsO/Cl Ketones as Oxidized Alkyne Equivalents: Redox‐Neutral Rhodium(III)‐Catalyzed CH Activation for the Synthesis of N‐Heterocycles 下载免费PDF全文
Dr. Da‐Gang Yu Francisco de Azambuja Prof. Dr. Frank Glorius 《Angewandte Chemie (International ed. in English)》2014,53(10):2754-2758
α‐Halo and pseudohalo ketones are used for the first time as C(sp3)‐based electrophiles in transition‐metal‐catalyzed C? H activation and as oxidized alkyne equivalents in RhIII‐catalyzed redox‐neutral annulations to generate diverse N‐heterocycles. This transformation is efficient and scalable. Due to the mild reaction conditions, a variety of functional groups could be tolerated. 相似文献
20.
Palladium‐Catalyzed Construction of Heteroatom‐Containing π‐Conjugated Systems by Intramolecular Oxidative CH/CH Coupling Reaction 下载免费PDF全文
Kenta Saito Dr. Prasanna Kumara Chikkade Prof. Dr. Motomu Kanai Prof. Dr. Yoichiro Kuninobu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(23):8365-8368
Synthesis of heteroatom‐containing ladder‐type π‐conjugated molecules was successfully achieved via a palladium‐catalyzed intramolecular oxidative C?H/C?H cross‐coupling reaction. This reaction provides a variety of π‐conjugated molecules bearing heteroatoms, such as nitrogen, oxygen, phosphorus, and sulfur atoms, and a carbonyl group. The π‐conjugated molecules were synthesized efficiently, even in gram scale, and larger π‐conjugated molecules were also obtained by a double C?H/C?H cross‐coupling reaction and successive oxidative cycloaromatization. 相似文献