共查询到20条相似文献,搜索用时 109 毫秒
1.
Dr. Samuel C. Scott Dr. Jamie A. Cadge Grace K. Boden Prof. John F. Bower Dr. Christopher A. Russell 《Angewandte Chemie (International ed. in English)》2023,62(23):e202301526
We describe a AuI complex of a hemi-labile (C^N) N-heterocyclic carbene ligand that is able to mediate oxidative addition of aryl iodides. Detailed computational and experimental investigations have been undertaken to verify and rationalize the oxidative addition process. Application of this initiation mode has resulted in the first examples of “exogenous oxidant-free” AuI/AuIII catalyzed 1,2-oxyarylations of ethylene and propylene. These demanding yet powerful processes establish these commodity chemicals as nucleophilic-electrophilic building blocks in catalytic reaction design. 相似文献
2.
Pengcheng Gao Jihong Xu Tongliang Zhou Dr. Yanhong Liu Prof. Dr. Elwira Bisz Dr. Błażej Dziuk Prof. Dr. Roger Lalancette Prof. Dr. Roman Szostak Prof. Dr. Dongju Zhang Prof. Dr. Michal Szostak 《Angewandte Chemie (International ed. in English)》2023,62(12):e202218427
In the last decade, major advances have been made in homogeneous gold catalysis. However, AuI/AuIII catalytic cycle remains much less explored due to the reluctance of AuI to undergo oxidative addition and the stability of the AuIII intermediate. Herein, we report activation of aryl halides at gold(I) enabled by NHC (NHC=N-heterocyclic carbene) ligands through the development of a new class of L-shaped heterobidentate ImPy (ImPy=imidazo[1,5-a]pyridin-3-ylidene) N,C ligands that feature hemilabile character of the amino group in combination with strong σ-donation of the carbene center in a rigid conformation, imposed by the ligand architecture. Detailed characterization and control studies reveal key ligand features for AuI/AuIII redox cycle, wherein the hemilabile nitrogen is placed at the coordinating position of a rigid framework. Given the tremendous significance of homogeneous gold catalysis, we anticipate that this ligand platform will find widespread application. 相似文献
3.
Jamie A. Cadge Hazel A. Sparkes John F. Bower Christopher A. Russell 《Angewandte Chemie (International ed. in English)》2020,59(16):6617-6621
The first isolated examples of intermolecular oxidative addition of alkenyl and alkynyl iodides to AuI are reported. Using a 5,5′‐difluoro‐2,2′‐bipyridyl ligated complex, oxidative addition of geometrically defined alkenyl iodides occurs readily, reversibly and stereospecifically to give alkenyl‐AuIII complexes. Conversely, reversible alkynyl iodide oxidative addition generates bimetallic complexes containing both AuIII and AuI centers. Stoichiometric studies show that both new initiation modes can form the basis for the development of C?C bond forming cross‐couplings. 相似文献
4.
Mathilde Rigoulet Olivier Thillaye du Boullay Dr. Abderrahmane Amgoune Dr. Didier Bourissou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(38):16768-16773
Heteroarylation of alkenes with aryl iodides was efficiently achieved with a (MeDalphos)AuCl complex through AuI/AuIII catalysis. The possibility to combine oxidative addition of aryl iodides and π-activation of alkenes at gold is demonstrated for the first time. The reaction is robust and general (>30 examples including internal alkenes, 5-, 6-, and 7-membered rings). It is regioselective and leads exclusively to trans addition products. The (P,N) gold complex is most efficient with electron-rich aryl substrates, which are troublesome with alternative photoredox/oxidative approaches. In addition, it provides a very unusual switch in regioselectivity from 5-exo to 6-endo cyclization between the Z and E isomers of internal alkenols. 相似文献
5.
Multicomponent Synthesis of Isoindolinone Frameworks via RhIII‐Catalysed in situ Directing Group‐Assisted Tandem Oxidative Olefination/Michael Addition
下载免费PDF全文
![点击此处可从《化学:亚洲杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Liang Wang Xi Liu Dr. Jian‐biao Liu Jun Shen Prof. Qun Chen Prof. Ming‐yang He 《化学:亚洲杂志》2018,13(7):765-769
A RhIII‐catalysed three‐component synthesis of isoindolinone frameworks via direct assembly of benzoyl chlorides, o‐aminophenols and activated alkenes has been developed. The process involves in situ generation of o‐aminophenol (OAP)‐based bidentate directing group (DG), RhIII‐catalysed tandem ortho C?H olefination and subsequent cyclization via aza‐Michael addition. This protocol exhibits good chemoselectivity and functional group tolerance. Computational studies showed that the presence of hydroxyl group on the N‐aryl ring could enhance the chemoselectivity of the reaction. 相似文献
6.
Wenliang Wang Meiling Ding Dr. Chuan-Gang Zhao Shuai Chen Prof. Dr. Chengjian Zhu Dr. Jie Han Dr. Weipeng Li Prof. Dr. Jin Xie 《Angewandte Chemie (International ed. in English)》2023,62(29):e202304019
Exploration of elementary reactions in organometallic catalysis is an important method with which to discover new reactions. In this article, we report a gold(I)-catalyzed iodo-alkynylation of benzyne involving the merging of challenging migratory insertion and an oxidative addition process in gold catalytic cycle. A wide range of structurally diverse alkynyl iodides are good coupling partners in this iodo-alkynylation transformation. Both aliphatic and aromatic alkynyl iodides can react with benzynes smoothly to afford highly functionalized 1,2-disubstituted aromatics in moderate to good yields. Its good functional group compatibility and late-stage application of complex molecules demonstrate its synthetic robustness. Studies of the mechanism reveals the feasibility of oxidative addition and the DFT calculations demonstrate the possible migratory insertion of benzyne into AuIII-carbon bonds in the AuI/AuIII redox catalytic cycle, representing an important step towards an elementary reaction in gold chemistry research. 相似文献
7.
Mathilde Rigoulet Olivier Thillaye du Boullay Abderrahmane Amgoune Didier Bourissou 《Angewandte Chemie (International ed. in English)》2020,59(38):16625-16630
Heteroarylation of alkenes with aryl iodides was efficiently achieved with a (MeDalphos)AuCl complex through AuI/AuIII catalysis. The possibility to combine oxidative addition of aryl iodides and π‐activation of alkenes at gold is demonstrated for the first time. The reaction is robust and general (>30 examples including internal alkenes, 5‐, 6‐, and 7‐membered rings). It is regioselective and leads exclusively to trans addition products. The (P,N) gold complex is most efficient with electron‐rich aryl substrates, which are troublesome with alternative photoredox/oxidative approaches. In addition, it provides a very unusual switch in regioselectivity from 5‐exo to 6‐endo cyclization between the Z and E isomers of internal alkenols. 相似文献
8.
Water‐Soluble Luminescent Cyclometalated Gold(III) Complexes with cis‐Chelating Bis(N‐Heterocyclic Carbene) Ligands: Synthesis and Photophysical Properties
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Faan‐Fung Hung Dr. Wai‐Pong To Dr. Jing‐Jing Zhang Dr. Chensheng Ma Prof. Dr. Wai‐Yeung Wong Prof. Dr. Chi‐Ming Che 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8604-8614
A new class of cyclometalated AuIII complexes containing various bidentate C‐deprotonated C^N and cis‐chelating bis(N‐heterocyclic carbene) (bis‐NHC) ligands has been synthesized and characterized. These are the first examples of AuIII complexes supported by cis‐chelating bis‐NHC ligands. [Au(C^N)(bis‐NHC)] complexes display emission in solutions under degassed condition at room temperature with emission maxima (λmax) at 498–633 nm and emission quantum yields of up to 10.1 %. The emissions are assigned to triplet intraligand (IL) π→π* transitions of C^N ligands. The AuIII complex containing a C^N (C‐deprotonated naphthalene‐substituted quinoline) ligand with extended π‐conjugation exhibits prompt fluorescence and phosphorescence of comparable intensity with λmax at 454 and 611 nm respectively. With sulfonate‐functionalized bis‐NHC ligand, four water‐soluble luminescent AuIII complexes, including those displaying both fluorescence and phosphorescence, were prepared. They show similar photophysical properties in water when compared with their counterparts in acetonitrile. The long phosphorescence lifetime of the water‐soluble AuIII complex with C‐deprotonated naphthalene‐substituted quinoline ligand renders it to function as ratiometric sensor for oxygen. Inhibitory activity of one of these water‐soluble AuIII complexes towards deubiquitinase (DUB) UCHL3 has been investigated; this complex also displayed a significant inhibitory activity with IC50 value of 0.15 μM . 相似文献
9.
Federica Guarra Alessio Terenzi Christine Pirker Rossana Passannante Dina Baier Ennio Zangrando Vanessa Gmez‐Vallejo Tarita Biver Chiara Gabbiani Walter Berger Jordi Llop Luca Salassa 《Angewandte Chemie (International ed. in English)》2020,59(39):17130-17136
AuIII complexes with N‐heterocyclic carbene (NHC) ligands have shown remarkable potential as anticancer agents, yet their fate in vivo has not been thoroughly examined and understood. Reported herein is the synthesis of new AuIII‐NHC complexes by direct oxidation with radioactive [124I]I2 as a valuable strategy to monitor the in vivo biodistribution of this class of compounds using positron emission tomography (PET). While in vitro analyses provide direct evidence for the importance of AuIII‐to‐AuI reduction to achieve full anticancer activity, in vivo studies reveal that a fraction of the AuIII‐NHC prodrug is not immediately reduced after administration but able to reach the major organs before metabolic activation. 相似文献
10.
Danielle van der Westhuizen Dr. Cathryn A. Slabber Dr. Manuel A. Fernandes Daniël F. Joubert Dr. George Kleinhans Dr. C. Johan van der Westhuizen Dr. André Stander Prof. Orde Q. Munro Dr. Daniela I. Bezuidenhout 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(32):8295-8307
The syntheses of bis(triazolium)carbazole precursors and their corresponding coinage metal (Au, Ag) complexes are reported. For alkylated triazolium salts, di- or tetranuclear complexes with bridging ligands were isolated, while the bis(aryl) analogue afforded a bis(carbene) AuI-CNC pincer complex suitable for oxidation to the redox-stable [AuIII(CNC)Cl]+ cation. Although the ligand salt and the [AuIII(CNC)Cl]+ complex were both notably cytotoxic toward the breast cancer cell line MDA-MB-231, the AuIII complex was somewhat more selective. Electrophoresis, viscometry, UV-vis, CD and LD spectroscopy suggest the cytotoxic [AuIII(CNC)Cl]+ complex behaves as a partial DNA intercalator. In silico screening indicated that the [AuIII(CNC)Cl]+ complex can target DNA three-way junctions with good specificity, several other regular B-DNA forms, and Z-DNA. Multiple hydrophobic π-type interactions involving T and A bases appear to be important for B-form DNA binding, while phosphate O⋅⋅⋅Au interactions evidently underpin Z-DNA binding. The CNC ligand effectively stabilizes the AuIII ion, preventing reduction in the presence of glutathione. Both the redox stability and DNA affinity of the hit compound might be key factors underpinning its cytotoxicity in vitro. 相似文献
11.
Dr. Riccardo Bonsignore Sophie R. Thomas Dr. Wim T. Klooster Dr. Simon J. Coles Dr. Robert L. Jenkins Dr. Didier Bourissou Prof. Giampaolo Barone Prof. Angela Casini 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(19):4226-4231
With the aim of exploiting new organometallic species for cross-coupling reactions, we report here on the AuIII-mediated Caryl−P bond formation occurring upon reaction of C^N cyclometalated AuIII complexes with phosphines. The [Au(C^N)Cl2] complex 1 featuring the bidentate 2-benzoylpyridine (CCON) scaffold was found to react with PTA (1,3,5-triaza-7-phosphaadamantane) under mild conditions, including in water, to afford the corresponding phosphonium 5 through C−P reductive elimination. A mechanism is proposed for the title reaction based on in situ 31P{1H} NMR and HR-ESI-MS analyses combined with DFT calculations. The C−P coupling has been generalized to other C^N cyclometalated AuIII complexes and other tertiary phosphines. Overall, this work provides new insights into the reactivity of cyclometalated AuIII compounds and establishes initial structure–activity relationships to develop AuIII-mediated C−P cross-coupling reactions. 相似文献
12.
A Stable Antiaromatic 5,20‐Dibenzoyl [28]Hexaphyrin(1.1.1.1.1.1): Core AuIII Metalation and Subsequent Peripheral BIII Metalation
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shin‐ichiro Ishida Takanori Soya Prof. Dr. Atsuhiro Osuka 《Angewandte Chemie (International ed. in English)》2018,57(41):13640-13643
5,20‐Dibenzoyl [28]hexaphyrin(1.1.1.1.1.1) was synthesized as the first hexaphyrin bearing meso‐aroyl substituents. The meso‐dibenzoyl substituents are hydrogen‐bonded with the pyrrolic protons to stabilize an antiaromatic dumbbell conformer. Core metalation of this hexaphyrin with AuIII afforded rectangular and aromatic [26]hexaphyrin bis‐AuIII complexes, the major isomer of which was reduced with NaBH4 to give its antiaromatic 28π bis‐AuIII complex. This complex allowed facile peripheral metalation with BIII owing to the peripheral benzoyl substituents. 相似文献
13.
Federica Guarra Alessio Terenzi Christine Pirker Rossana Passannante Dina Baier Ennio Zangrando Vanessa Gómez-Vallejo Tarita Biver Chiara Gabbiani Walter Berger Jordi Llop Luca Salassa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(39):17278-17284
AuIII complexes with N-heterocyclic carbene (NHC) ligands have shown remarkable potential as anticancer agents, yet their fate in vivo has not been thoroughly examined and understood. Reported herein is the synthesis of new AuIII-NHC complexes by direct oxidation with radioactive [124I]I2 as a valuable strategy to monitor the in vivo biodistribution of this class of compounds using positron emission tomography (PET). While in vitro analyses provide direct evidence for the importance of AuIII-to-AuI reduction to achieve full anticancer activity, in vivo studies reveal that a fraction of the AuIII-NHC prodrug is not immediately reduced after administration but able to reach the major organs before metabolic activation. 相似文献
14.
Facilitating Gold Redox Catalysis with Electrochemistry: An Efficient Chemical‐Oxidant‐Free Approach
Xiaohan Ye Pengyi Zhao Shuyao Zhang Yanbin Zhang Qilin Wang Chuan Shan Lukasz Wojtas Hao Guo Hao Chen Xiaodong Shi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(48):17386-17390
Due to the high oxidation potential between AuI and AuIII, gold redox catalysis requires at least stoichiometric amounts of a strong oxidant. We herein report the first example of an electrochemical approach in promoting gold‐catalyzed oxidative coupling of terminal alkynes. Oxidation of AuI to AuIII was successfully achieved through anode oxidation, which enabled facile access to either symmetrical or unsymmetrical conjugated diynes through homo‐coupling or cross‐coupling. This report extends the reaction scope of this transformation to substrates that are not compatible with strong chemical oxidants and potentiates the versatility of gold redox chemistry through the utilization of electrochemical oxidative conditions. 相似文献
15.
Ligand‐Assisted Gold‐Catalyzed Cross‐Coupling with Aryldiazonium Salts: Redox Gold Catalysis without an External Oxidant
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rong Cai Mei Lu Ellen Y. Aguilera Yumeng Xi Dr. Novruz G. Akhmedov Dr. Jeffrey L. Petersen Prof. Dr. Hao Chen Prof. Dr. Xiaodong Shi 《Angewandte Chemie (International ed. in English)》2015,54(30):8772-8776
Gold‐catalyzed C(sp)–C(sp2) and C(sp2)–C(sp2) cross‐coupling reactions are accomplished with aryldiazonium salts as the coupling partner. With the assistance of bpy ligand, gold(I) species were oxidized to gold(III) by diazonium without any external oxidants. Monitoring the reaction with NMR and ESI‐MS provided strong evidence for the nitrogen extrusion followed by AuIII reductive elimination as the key step. 相似文献
16.
Dr. Chiara Nardon Dr. Federica Chiara Leonardo Brustolin Dr. Alberto Gambalunga Dr. Francesco Ciscato Dr. Andrea Rasola Prof. Andrea Trevisan Prof. Dolores Fregona 《ChemistryOpen》2015,4(2):183-191
Transition metals offer many possibilities in developing potent chemotherapeutic agents. They are endowed with a variety of oxidation states, allowing for the selection of their coordination numbers and geometries via the choice of proper ligands, leading to the tuning of their final biological properties. We report here on the synthesis, physico-chemical characterization, and solution behavior of two gold(III) pyrrolidinedithiocarbamates (PDT), namely [AuIIIBr2(PDT)] and [AuIIICl2(PDT)]. We found that the bromide derivative was more effective than the chloride one in inducing cell death for several cancer cell lines. [AuIIIBr2(PDT)] elicited oxidative stress with effects on the permeability transition pore, a mitochondrial channel whose opening leads to cell death. More efficient antineoplastic strategies are required for the widespread burden that is cancer. In line with this, our results indicate that [AuIIIBr2(PDT)] is a promising antineoplastic agent that targets cellular components with crucial functions for the survival of tumor cells. 相似文献
17.
Hideaki Murasugi Dr. Shohei Kumagai Dr. Hiroaki Iguchi Prof. Dr. Masahiro Yamashita Dr. Shinya Takaishi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9885-9891
Crystal structures of a series of organic–inorganic hybrid gold iodide perovskites, formulated as A2[AuII2][AuIIII4] [A=methylammonium (MA) ( 1 ) and formamidinium (FA) ( 2 )], A′2[I3]1−x[AuII2]x[AuIIII4] [A′=imidazolium (IMD) ( 3 ), guanidinium (GUA) ( 4 ), dimethylammonium (DMA) ( 5 ), pyridinium (PY) ( 6 ), and piperizinium (PIP) ( 7 )], systematically changed depending on the cation size. In addition, triiodide (I3−) ions were partly incorporated into the AuI2− sites of 3 – 7 , whereas they were not incorporated into those of 1 and 2 . Such a difference comes from the size of the organic cation. Optical absorption spectra showed characteristic intervalence charge-transfer bands from AuI to AuIII species, and the optical band gap increased as the size of the cation became larger. 相似文献
18.
Ibon Odriozola Nerea Ormategui Iraida Loinaz José A. Pomposo Hans J. Grande 《Macromolecular Symposia》2008,266(1):96-100
Summary: Coinage metal salts (e.g. AuIII, AgI and CuII salts) readily react with thiols to give the corresponding metal(I) thiolates. These thiolate species are known to either self-assemble into insoluble polymeric species or to form soluble oligomers, depending on the nature of the thiol ligand. Here we demonstrate that this self-assembling ability can be applied to create supramolecular hydrogels. Glutathione (GSH), a naturally occurring tripeptide, has been used in combination with AuIII, AgI and CuII salts to obtain pH responsive hydrogels that are able to gelate 100 times their weight in water. 相似文献
19.
Chetan C. Chintawar Amit K. Yadav Nitin T. Patil 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(29):11906-11911
Herein, we disclose the gold-catalyzed 1,2-diarylation of alkenes through the interplay of ligand-enabled AuI/AuIII catalysis with the idiosyncratic π-activation mode of gold complexes. Unlike the classical migratory-insertion-based approach to 1,2-diarylation, the present approach not only circumvents the formation of direct Ar−Ar′ coupling and Heck-type side products but more intriguingly demonstrates reactivity and selectivity complementary to those of previously known metal catalysis (Pd, Ni, or Cu). Detailed investigations to underpin the mechanistic scenario revealed oxidative addition of aryl iodides to an AuI complex to be the rate-limiting step owing to the non-innocent nature of the aryl alkene. 相似文献
20.
Shigeo Tazuke Michihiko Asai Seizo Okamura 《Journal of polymer science. Part A, Polymer chemistry》1968,6(7):1809-1824
The polymerization of N-vinylcarbazole (VCZ) initiated by sodium chloroaurate (NaAuCl4·2H2O) in nitrobenzene was studied at 30°C. The rate of polymerization (Rp) is proportional to [AuIII] [VCZ] after a short induction period. When reducing agents (ascorbic acid, ferrocene, or mercury metal) are added to the system, the rate of polymerization in the dark increases. The Rp is relatively unaffected by addition of water and N-ethylcarbazole, but the polymerization is completely inhibited in the presence of ammonia. Oxygen and DPPH act as neither inhibitors nor retarders. Kinetic treatments based on the assumption that the active initiating species is AuII produced by reduction of AuIII by VCZ and other reducing agents explain the experimental results very well. 相似文献