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1.
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
2.
Late‐Stage Peptide Diversification by Bioorthogonal Catalytic CH Arylation at 23 °C in H2O
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Dr. Yingjun Zhu Michaela Bauer Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):9980-9983
The step‐economical late‐stage diversification of tryptophan‐containing peptides was accomplished through chemo‐ and site‐selective palladium‐catalyzed C?H arylation under exceedingly mild reaction conditions. Thus, the C?H functionalization occurred efficiently at 23 °C with a catalyst loading as low as 0.5 mol %, and/or in H2O. 相似文献
3.
Fujiwara–Moritani Reaction of Weinreb Amides using a Ruthenium‐Catalyzed C−H Functionalization Reaction
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The ruthenium‐catalyzed Fujiwara–Moritani reaction (oxidative‐Heck reaction) of Weinreb amides is reported herein. The reaction affords exclusively ortho‐C?H olefination products, has excellent substrate scope and tolerates halogen functionalities, which increase the synthetic utility of the method. A variety of activated olefins as well as styrenes can be employed as coupling partners. 相似文献
4.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(47):15327-15331
The para ‐selective C−H alkylation of aniline derivatives furnished with a pyrimidine auxiliary is herein reported. This reaction is proposed to take place via an N−H‐activated cyclometalate formed in situ. Experimental and DFT mechanistic studies elucidate a dual role of the ruthenium catalyst. Here the ruthenium catalyst can undergo cyclometalation by N−H metalation (as opposed to C−H metalation in meta ‐selective processes) and form a redox active ruthenium species, to enable site‐selective radical addition at the para position. 相似文献
5.
Zhongxing Huang Chengpeng Wang Prof. Dr. Guangbin Dong 《Angewandte Chemie (International ed. in English)》2016,55(17):5299-5303
Described is a new hydrazone‐based exo‐directing group (DG) strategy developed for the functionalization of unactivated primary β C?H bonds of aliphatic amines. Conveniently synthesized from protected primary amines, the hydrazone DGs are shown to site‐selectively promote the β‐acetoxylation and tosyloxylation via five‐membered exo‐palladacycles. Amines with a wide scope of skeletons and functional groups are tolerated. Moreover, the hydrazone DG can be readily removed, and a one‐pot C?H acetoxylation/DG removal protocol was also discovered. 相似文献
6.
Single‐Component Phosphinous Acid Ruthenium(II) Catalysts for Versatile C−H Activation by Metal–Ligand Cooperation
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Prof. Dr. Dmitri Gelman Prof. Dr. Simon J. Garden Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(4):1248-1252
Well‐defined ruthenium(II) phosphinous acid (PA) complexes enabled chemo‐, site‐, and diastereoselective C?H functionalization of arenes and alkenes with ample scope. The outstanding catalytic activity was reflected by catalyst loadings as low as 0.75 mol %, and the most step‐economical access reported to date to angiotensin II receptor antagonist blockbuster drugs. Mechanistic studies indicated a kinetically relevant C?X cleavage by a single‐electron transfer (SET)‐type elementary process, and provided evidence for a PA‐assisted C?H ruthenation step. 相似文献
7.
Parthasarathy Gandeepan Julian Koeller Korkit Korvorapun Jens Mohr Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2019,58(29):9820-9825
Visible‐light‐induced ruthenium catalysis has enabled remote C?H alkylations with excellent levels of position control under exceedingly mild conditions at room temperature. The metallaphotocatalysis occurred under exogenous‐photosensitizer‐free conditions and features an ample substrate scope. The robust nature of the photo‐induced mild meta‐C?H functionalization is reflected by the broad functional group tolerance, and the reaction can be carried out in an operationally simple manner, setting the stage for challenging secondary and tertiary meta‐C?H alkylations by ruthenaphotoredox catalysis. 相似文献
8.
Dr. Yoshinari Sawama Yuki Yabe Hiroki Iwata Dr. Yuta Fujiwara Dr. Yasunari Monguchi Prof. Dr. Hironao Sajiki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(51):16436-16442
Deuterium‐labeled sugars can be utilized as powerful tools for the architectural analyses of high‐sugar‐containing molecules represented by the nucleic acids and glycoproteins, and chiral building blocks for the syntheses of new drug candidates (heavy drugs) due to their potential characteristics, such as simplifying the 1H NMR spectra and the stability of C? D bonds compared with C? H bonds. We have established a direct and efficient synthetic method of deuterated sugars from non‐labeled sugars by using the heterogeneous Ru/C‐catalyzed H–D exchange reaction in D2O under a hydrogen atmosphere with perfect chemo‐ and stereoselectivities. The direct H–D exchange reaction can selectively proceed on carbons adjacent to the free hydroxyl groups, and the deuterium labeling of various pyranosides (such as glucose and disaccharides), as well as furanosides, represented by ribose and deoxyribose was realized. Furthermore, the desired number of deuterium atoms can be freely incorporated into selected positions by the site‐selective protection of the hydroxyl groups using acetal‐type protective groups because the deuterium exchange reaction never proceeds on positions adjacent to the protected hydroxyl groups. 相似文献
9.
Norihito Fukui Prof. Dr. Hideki Yorimitsu Prof. Dr. Atsuhiro Osuka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18476-18483
A meso–meso‐linked diphenylamine‐fused porphyrin dimer and its methoxy‐substituted analogue were synthesized from a meso–meso‐linked porphyrin dimer by a reaction sequence involving Ir‐catalyzed β‐selective borylation, iodination, meso‐chlorination, and SNAr reactions with diarylamines followed by electron‐transfer‐mediated intramolecular double C?H/C?I coupling. While these dimers commonly display characteristic split Soret bands and small oxidation potentials, they produced different products upon oxidation with tris(4‐bromophenyl)aminium hexachloroantimonate. Namely, the diphenylamine‐fused porphyrin dimer was converted into a dicationic closed‐shell quinonoidal dimer, while the methoxy‐substituted dimer gave a meso–meso, β‐β doubly linked porphyrin dimer. 相似文献
10.
Dr. Youai Qiu Cong Tian Leonardo Massignan Torben Rogge Prof. Dr. Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2018,57(20):5818-5822
Electrocatalysis has been identified as a powerful strategy for organometallic catalysis, and yet electrocatalytic C?H activation is restricted to strongly N‐coordinating directing groups. The first example of electrocatalytic C?H activation by weak O‐coordination is presented, in which a versatile ruthenium(II) carboxylate catalyst enables electrooxidative C?H/O?H functionalization for alkyne annulations in the absence of metal oxidants; thereby exploiting sustainable electricity as the sole oxidant. Mechanistic insights provide strong support for a facile organometallic C?H ruthenation and an effective electrochemical reoxidation of the key ruthenium(0) intermediate. 相似文献
11.
Regioselective Ruthenium‐Catalyzed Carbonylative Direct Arylation of Five‐Membered and Condensed Heterocycles
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Jola Pospech Dr. Anis Tlili Dr. Anke Spannenberg Dr. Helfried Neumann Prof. Dr. Matthias Beller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(11):3135-3141
A ruthenium‐catalyzed carbonylative C?H bond arylation process for the three‐component synthesis of complex aryl–(hetero)aryl ketones in an aqueous solution has been developed. By exploiting the ortho‐activating effect of nitrogen‐containing directing groups, a regioselective, successive twofold C(sp2)?C(sp2) bond formation has been achieved. This straightforward catalytic process provides access to versatile products prevalent in multiple bioactive compounds and supplies a valuable functional group for subsequent transformations. 相似文献
12.
Wenbo Ma Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(41):13925-13928
Cationic ruthenium(II) complexes enabled oxidative alkenylations of phenols bearing easily cleavable directing groups. The optimized catalytic system allowed twofold C? H bond activations with excellent chemo‐, site‐, and diastereoselectivities. The double C? H functionalization process proceeded efficiently in an aerobic fashion under an atmosphere of ambient air. Detailed mechanistic studies were performed and provided strong support for an initial reversible C? H bond activation by the formation of six‐membered ruthenacycles as the key intermediates. 相似文献
13.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(6):1579-1582
Methods for positionally selective remote C−H functionalizations are in high demand. Herein, we disclose the first heterogeneous ruthenium catalyst for meta ‐selective C−H functionalizations, which enabled remote halogenations with excellent site selectivity and ample scope. The versatile heterogeneous Ru@SiO2 catalyst was broadly applicable and could be easily recovered and reused, which set the stage for the direct fluorescent labeling of purines. In contrast to palladium, rhodium, iridium, or cobalt complexes, solely the ruthenium catalysis manifold provided access to meta ‐halogenated purine derivatives, illustrating the unique power of ruthenium C−H activation catalysis. 相似文献
14.
Ruthenium–Porphyrin‐Catalyzed Diastereoselective Intramolecular Alkyl Carbene Insertion into CH Bonds of Alkyl Diazomethanes Generated In Situ from N‐Tosylhydrazones
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Zhen Guo Jinhu Wei Prof. Dr. Chi‐Ming Che 《Angewandte Chemie (International ed. in English)》2014,53(51):14175-14180
With a ruthenium–porphyrin catalyst, alkyl diazomethanes generated in situ from N‐tosylhydrazones efficiently underwent intramolecular C(sp3)? H insertion of an alkyl carbene to give substituted tetrahydrofurans and pyrrolidines in up to 99 % yield and with up to 99:1 cis selectivity. The reaction displays good tolerance of many functionalities, and the procedure is simple without the need for slow addition with a syringe pump. From a synthetic point of view, the C? H insertion of N‐tosylhydrazones can be viewed as reductive coupling between a C?O bond and a C? H bond to form a new C? C bond, since N‐tosylhydrazones can be readily prepared from carbonyl compounds. This reaction was successfully applied in a concise synthesis of (±)‐pseudoheliotridane. 相似文献
15.
J. R. Wells 《国际化学动力学杂志》2004,36(10):534-544
A bimolecular rate constant,kDHO, of (29 ± 9) × 10?12 cm3 molecule?1 s?1 was measured using the relative rate technique for the reaction of the hydroxyl radical (OH) with 3,5‐dimethyl‐1‐hexyn‐3‐ol (DHO, HC?CC(OH)(CH3)CH2CH(CH3)2) at (297 ± 3) K and 1 atm total pressure. To more clearly define DHO's indoor environment degradation mechanism, the products of the DHO + OH reaction were also investigated. The positively identified DHO/OH reaction products were acetone ((CH3)2C?O), 3‐butyne‐2‐one (3B2O, HC?CC(?O)(CH3)), 2‐methyl‐propanal (2MP, H(O?)CCH(CH3)2), 4‐methyl‐2‐pentanone (MIBK, CH3C(?O)CH2CH(CH3)2), ethanedial (GLY, HC(?O)C(?O)H), 2‐oxopropanal (MGLY, CH3C(?O)C(?O)H), and 2,3‐butanedione (23BD, CH3C(?O)C(?O)CH3). The yields of 3B2O and MIBK from the DHO/OH reaction were (8.4 ± 0.3) and (26 ± 2)%, respectively. The use of derivatizing agents O‐(2,3,4,5,6‐pentalfluorobenzyl)hydroxylamine (PFBHA) and N,O‐bis(trimethylsilyl)trifluoroacetamide (BSTFA) clearly indicated that several other reaction products were formed. The elucidation of these other reaction products was facilitated by mass spectrometry of the derivatized reaction products coupled with plausible DHO/OH reaction mechanisms based on previously published volatile organic compound/OH gas‐phase reaction mechanisms. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 534–544, 2004 相似文献
16.
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
17.
Exploring Bis(cyclometalated) Ruthenium(II) Complexes as Active Catalyst Precursors: Room‐Temperature Alkene–Alkyne Coupling for 1,3‐Diene Synthesis
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Jing Zhang Dr. Angel Ugrinov Prof. Dr. Yong Zhang Prof. Dr. Pinjing Zhao 《Angewandte Chemie (International ed. in English)》2014,53(32):8437-8440
Described is the development of a new class of bis(cyclometalated) ruthenium(II) catalyst precursors for C? C coupling reactions between alkene and alkyne substrates. The complex [(cod)Ru(3‐methallyl)2] reacts with benzophenone imine or benzophenone in a 1:2 ratio to form bis(cyclometalated) ruthenium(II) complexes ( 1 ). The imine‐ligated complex 1 a promoted room‐temperature coupling between acrylic esters and amides with internal alkynes to form 1,3‐diene products. A proposed catalytic cycle involves C? C bond formation by oxidative cyclization, β‐hydride elimination, and C? H bond reductive elimination. This RuII/RuIV pathway is consistent with the observed catalytic reactivity of 1 a for mild tail‐to‐tail methyl acrylate dimerization and for cyclobutene formation by [2+2] norbornene/alkyne cycloaddition. 相似文献
18.
Ruthenium(II)‐Catalyzed C−H Activation of Imidamides and Divergent Couplings with Diazo Compounds: Substrate‐Controlled Synthesis of Indoles and 3H‐Indoles
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Yunyun Li Dr. Zisong Qi Dr. He Wang Xifa Yang Prof. Xingwei Li 《Angewandte Chemie (International ed. in English)》2016,55(39):11877-11881
Indoles are an important structural motif that is commonly found in biologically active molecules. In this work, conditions for divergent couplings between imidamides and acceptor–acceptor diazo compounds were developed that afforded NH indoles and 3H‐indoles under ruthenium catalysis. The coupling of α‐diazoketoesters afforded NH indoles by cleavage of the C(N2)?C(acyl) bond whereas α‐diazomalonates gave 3H‐indoles by C?N bond cleavage. This reaction constitutes the first intermolecular coupling of diazo substrates with arenes by ruthenium‐catalyzed C?H activation. 相似文献
19.
Theoretical mechanism for selective catalysis of ruthenium complex catalyzed hydroboration of terminal alkynes to Z‐vinylboronates
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Chuanzhi Sun Mingshu Liu Haitao Sun Fang Hang Nan Sun Dezhan Chen 《International journal of quantum chemistry》2015,115(2):59-67
Detailed mechanism of the hydroboration of terminal alkynes catalyzed by ruthenium complex was studied using density functional theory. The calculated results suggest that the reaction proceeds in two steps: alkyne rearrangement and catalyst regeneration. Vinylboronate products with E and Z configuration are formed in this reaction. Path A forming Z‐vinylboronate is the preferred pathway. Noncovalent interaction between B? H bond and Ru centre determines the preferred pathway of the reaction. The Egap of HOMO‐LUMO for the reactant is lowered with the assistance of ruthenium–borane complex (Ru–Cat) formation. A hypothetical control model using 1, 2‐dimethyl acetylene (internal alkyne) and styrene (terminal alkene) as the reaction substrates was designed. The calculated results suggest that the activation barrier of the rate‐determining process is too high, which make the hydroboration reaction of styrene and 1, 2‐dimethyl acetylene (CH3C‐CCH3) hard to occur. The results uncover the selectivity of the ruthenium complex for hydroboration of terminal alkynes. © 2014 Wiley Periodicals, Inc. 相似文献
20.
Zirconium‐Mediated Multicomponent Reactions of 1,3‐Butadiynes with Ylidenemalononitriles to Form Functionalized 1,8‐Naphthyridine and Cyclopenta[b]pyridine Derivatives
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Dr. Shasha Yu Renhong Sun Haoyi Chen Xin Xie Prof. Yuanhong Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(4):1420-1424
Zirconocene‐mediated multicomponent reactions of 1,3‐butadiynes with ylidenemalononitriles in the absence or presence of CuCl have been developed. In the absence of CuCl, 1,3‐butadiyne couples with three molecules of ylidenemalononitriles to yield azazirconacycles bearing a hexahydro‐1,8‐naphthyridine skeleton with high stereoselectivity. In the presence of CuCl, cyclopenta[b]pyridine or cyclopenta[b]quinolin‐1‐one derivatives are obtained via transmetalation of Zr?C bond to Cu?C bond as the key reaction step. These domino‐type reactions proceed with high chemo‐, regio‐ and/or stereoselectivities, and allowing the formation of multiple C?N and C?C bonds in a single operation. 相似文献