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1.
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
2.
Rhodium(III)‐Catalyzed ortho Alkenylation of N‐Phenoxyacetamides with N‐Tosylhydrazones or Diazoesters through CH Activation 下载免费PDF全文
Fangdong Hu Ying Xia Fei Ye Zhenxing Liu Prof. Dr. Chen Ma Prof. Dr. Yan Zhang Prof. Dr. Jianbo Wang 《Angewandte Chemie (International ed. in English)》2014,53(5):1364-1367
A coupling reaction of N‐phenoxyacetamides with N‐tosylhydrazones or diazoesters through RhIII‐catalyzed C? H activation is reported. In this reaction, ortho‐alkenyl phenols were obtained in good yields and with excellent regio‐ and stereoselectivity. Rh–carbene migratory insertion is proposed as the key step in the reaction mechanism. 相似文献
3.
Amidines for Versatile Ruthenium(II)‐Catalyzed Oxidative CH Activations with Internal Alkynes and Acrylates 下载免费PDF全文
Jie Li Dr. Michael John Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(18):5403-5408
Cationic ruthenium complexes derived from KPF6 or AgOAc enabled efficient oxidative C?H functionalizations on aryl and heteroaryl amidines. Thus, oxidative annulations of diversely decorated internal alkynes provided expedient access to 1‐aminoisoquinolines, while catalyzed C?H activations with substituted acrylates gave rise to structurally novel 1‐iminoisoindolines. The powerful ruthenium(II) catalysts displayed a remarkably high site‐, regio‐ and, chemoselectivity. Therefore, the catalytic system proved tolerant of a variety of important electrophilic functional groups. Detailed mechanistic studies provided strong support for the cationic ruthenium(II) catalysts to operate by a facile, reversible C?H activation. 相似文献
4.
Wen Ai Xueyan Yang Yunxiang Wu Xuan Wang Prof. Yuanchao Li Dr. Yaxi Yang Dr. Bing Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(52):17653-17657
A RhIII‐catalyzed procedure for the C7‐selective C?H alkylation of various indolines with α‐diazo compounds at room temperature is reported. The advantages of this process are: 1) simple, mild, and pH‐neutral reaction conditions, 2) broad substrate scope, 3) complete regioselectivity, 4) no need for an external oxidant, and 5) N2 as the sole byproduct. Furthermore, alkylation and bis‐alkylation of carbazoles at the C1 and C8 positions have also been developed. More significantly, for the first time, a successful IrIII‐catalyzed intermolecular insertion of arene C?H bonds into α‐diazo compounds is reported. 相似文献
5.
Yasuaki Kawaguchi Dr. Shigeo Yasuda Akira Kaneko Yuki Oura Prof. Dr. Chisato Mukai 《Angewandte Chemie (International ed. in English)》2014,53(29):7608-7612
The efficient RhI‐catalyzed cycloisomerization of benzylallene‐alkynes produced the tricyclo[9.4.0.03,8]pentadecapentaene skeleton through a C? H bond activation in good yields. A plausible reaction mechanism proceeds via oxidative addition of the acetylenic C? H bond to RhI, an ene‐type cyclization to the vinylidenecarbene–RhI intermediate, and an electrophilic aromatic substitution with the vinylidenecarbene species. It was proposed based on deuteration and competition experiments. 相似文献
6.
Enantioselective Synthesis of Spiroindenes by Enol‐Directed Rhodium(III)‐Catalyzed CH Functionalization and Spiroannulation 下载免费PDF全文
Dr. Suresh Reddy Chidipudi Dr. David J. Burns Imtiaz Khan Prof. Hon Wai Lam 《Angewandte Chemie (International ed. in English)》2015,54(47):13975-13979
Chiral cyclopentadienyl rhodium complexes promote highly enantioselective enol‐directed C(sp2)‐H functionalization and oxidative annulation with alkynes to give spiroindenes containing all‐carbon quaternary stereocenters. High selectivity between two possible directing groups, as well as control of the direction of rotation in the isomerization of an O‐bound rhodium enolate into the C‐bound isomer, appear to be critical for high enantiomeric excesses. 相似文献
7.
Iridium‐Catalyzed Enantioselective CH Alkylation of Ferrocenes with Alkenes Using Chiral Diene Ligands 下载免费PDF全文
Prof. Dr. Takanori Shibata Tsubasa Shizuno 《Angewandte Chemie (International ed. in English)》2014,53(21):5410-5413
The first catalytic and enantioselective C? H alkylation of ferrocene derivatives with various alkenes was achieved. A cationic iridium complex, having a chiral diene ligand, and an isoquinolyl moiety as a directing group are essential for regioselective and enantioselective C? H bond activation. 相似文献
8.
Regioselective C3 Alkenylation of 4 H‐pyrido[1,2‐a]pyrimidin‐4‐ones via Palladium‐Catalyzed CH Activation 下载免费PDF全文
Dr. Wenjie Liu Dr. Shaohua Wang Qi Zhang Jingwen Yu Jiahe Li Zhiwei Xie Prof. Hua Cao 《化学:亚洲杂志》2014,9(9):2436-2439
A general and efficient palladium‐catalyzed direct C3 alkenylation of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones using AgOAc/O2 as the oxidant has been developed. A variety of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones were successfully coupled with acrylate esters, styrenes, methylvinylketone, and acrylamide in moderate to excellent yields. The reaction exhibited complete regio‐ and stereoselectivity. This transformation provides an attractive new approach to functionalize 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones. 相似文献
9.
Ruthenium(II)‐Catalyzed Oxidative CH Alkenylations of Sulfonic Acids,Sulfonyl Chlorides and Sulfonamides 下载免费PDF全文
Wenbo Ma Ruhuai Mei Giammarco Tenti Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):15248-15251
Twofold C?H functionalization of aromatic sulfonic acids was achieved with an in situ generated ruthenium(II) catalyst. The optimized cross‐dehydrogenative alkenylation protocol proved applicable to differently substituted arenes and a variety of alkenes, including vinyl arenes, sulfones, nitriles and ketones. The robustness of the ruthenium(II) catalyst was demonstrated by the chemoselective oxidative olefination of sulfonamides as well as sulfonyl chlorides. Mechanistic studies provided support for a reversible, acetate‐assisted C?H ruthenation, along with a subsequent olefin insertion. 相似文献
10.
Dr. Liene Grigorjeva Prof. Olafs Daugulis 《Angewandte Chemie (International ed. in English)》2014,53(38):10209-10212
A method for cobalt‐catalyzed, aminoquinoline‐ and picolinamide‐directed C(sp2)? H bond alkenylation by alkynes was developed. The method shows excellent functional‐group tolerance and both internal and terminal alkynes are competent substrates for the coupling. The reaction employs a Co(OAc)2?4 H2O catalyst, Mn(OAc)2 co‐catalyst, and oxygen (from air) as a terminal oxidant. 相似文献
11.
Dr. Vaibhav P. Mehta Dr. José‐Antonio García‐López Prof. Michael F. Greaney 《Angewandte Chemie (International ed. in English)》2014,53(6):1529-1533
Three orthogonal cascade C? H functionalization processes are described, based on ruthenium‐catalyzed C? H alkenylation. 1‐Indanones, indeno indenes, and indeno furanones were accessed through cascade pathways by using arylacetophenones as substrates under conditions of catalytic [{Ru(p‐cymene)Cl2}2] and stoichiometric Cu(OAc)2. Each transformation uses C? H functionalization methods to form C? C bonds sequentially, with the indeno furanone synthesis featuring a C? O bond formation as the terminating step. This work demonstrates the power of ruthenium‐catalyzed alkenylation as a platform reaction to develop more complex transformations, with multiple C? H functionalization steps taking place in a single operation to access novel carbocyclic structures. 相似文献
12.
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
13.
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
14.
15.
Fei Pan Bin Wu Dr. Zhang‐Jie Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6487-6490
A copper‐catalyzed intramolecular amidation of unactivated C(sp3)?H bonds to construct indoline derivatives has been developed. Such an amidation proceeded well at primary C?H bonds preferred to secondary C?H bonds. The transformation owned a broad substrate scope. The corresponding indolines were obtained in good to excellent yields. N‐Formal and other carbonyl groups were suitable and were easily deprotected and transformed into methyl or long‐chained alkyl groups. Preliminary mechanistic studies suggested a radical pathway. 相似文献
16.
Hydroarylations of Heterobicyclic Alkenes through Rhodium‐Catalyzed Directed CH Functionalizations of S‐Aryl Sulfoximines 下载免费PDF全文
Dr. Wanrong Dong Dr. Kanniyappan Parthasarathy Ying Cheng Dr. Fangfang Pan Prof. Dr. Carsten Bolm 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(48):15732-15736
Rhodium‐catalyzed directed CH‐functionalizations have been used in hydroarylations of heterobicyclic alkenes with NH‐sulfoximines. Unexpectedly, the bicyclic framework is retained, resulting in the formation of addition products being attractive intermediates for functionalized molecules that are difficult to prepare by other means. 相似文献
17.
Acylsilanes in Rhodium(III)‐Catalyzed Directed Aromatic C–H Alkenylations and Siloxycarbene Reactions with CC Double Bonds 下载免费PDF全文
Peter Becker Dr. Daniel L. Priebbenow Ramona Pirwerdjan Prof. Dr. Carsten Bolm 《Angewandte Chemie (International ed. in English)》2014,53(1):269-271
Acylsilanes are known to undergo a 1,2‐silicon‐to‐oxygen migration under thermal or photochemical conditions to form siloxycarbenes. However, there are few reports regarding the application of siloxycarbenes in organic synthesis and surprisingly, their reaction with C? C double or triple bonds remains virtually unexplored. To facilitate such a study, previously inaccessible aromatic acylsilanes containing an ortho‐tethered C? C double bond were identified as suitable substrates. To access these key intermediates, we developed a new synthetic method utilizing a rhodium‐catalyzed oxidative Heck‐type olefination involving the application of an acylsilane moiety as a directing group. When exposed to visible‐light irradiation, the ortho‐olefinated acylsilanes underwent a smooth intramolecular cyclization process to afford valuable indanone derivatives in quantitative yields. This result paves the way for the development of new transformations involving siloxycarbene intermediates. 相似文献
18.
Christopher J. Teskey Andrew Y. W. Lui Prof. Michael F. Greaney 《Angewandte Chemie (International ed. in English)》2015,54(40):11677-11680
The first example of a transition‐metal‐catalyzed, meta‐selective C? H bromination procedure is reported. In the presence of catalytic [{Ru(p‐cymene)Cl2}2], tetrabutylammonium tribromide can be used to functionalize the meta C? H bond of 2‐phenylpyridine derivatives, thus affording difficult to access products which are highly predisposed to further derivatization. We demonstrate this utility with one‐pot bromination/arylation and bromination/alkenylation procedures to deliver meta‐arylated and meta‐alkenylated products, respectively, in a single step. 相似文献
19.
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
20.
M. Sc. Fanzhi Yang Karsten Rauch M. Sc. Katharina Kettelhoit Prof. Dr. Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2014,53(42):11285-11288
Versatile ruthenium(II) complexes allow for site‐selective C? H oxygenations with weakly‐coordinating aldehydes. The challenging C? H functionalizations proceed with high chemoselectivity by rate‐determining C? H metalation. The new method features an ample substrate scope, which sets the stage for the step‐economical preparation of various bioactive heterocycles. 相似文献