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1.
The Renaissance of an Old Problem: Highly Regioselective Carboxylation of 2‐Alkynyl Bromides with Carbon Dioxide 下载免费PDF全文
Bukeyan Miao Gen Li Prof. Dr. Shengming Ma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17224-17228
A steric effect‐controlled, zinc‐mediated carboxylation of different 2‐alkynyl bromides under an atmospheric pressure of CO2 has been developed by careful tuning of different reaction parameters, including the metal, solvent, temperature, and additive. 2‐Substituted 2,3‐allenoic acids were afforded from primary 2‐alkynyl bromides, whereas the carboxylation of secondary 2‐alkynyl bromides yielded 3‐alkynoic acids in decent yields. A rationale for the observed regioselectivity has been proposed. 相似文献
2.
We developed a method for the synthesis of alkynyl amides via the carbonylation of alkynoic acids and C-N activation of tertiary amines. The reaction of alkynoic acid and tertiary amine with carbon monoxide using a palladium catalyst in the presence of oxygen, KI, and K3PO4, gave the desired alkynyl amides in good yields. 相似文献
3.
Chunhong Wang Qi Cui Zhixin Zhang Prof. Zhu-Jun Yao Dr. Shaozhong Wang Prof. Zhi-Xiang Yu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9821-9826
1,3-Azaprotio transfer of propargylic α-ketocarboxylate oximes, a new type of alkynyl oximes featuring an ester tether, has been explored by taking advantage of gold catalysis. The incorporation of an oxygen atom to the chain of alkynyl oximes led to the formation of two different oxa-cyclic nitrones. It was found that internal alkynyl oximes with an E-configuration deliver five-membered nitrones, whereas terminal alkynyl oximes with an E-configuration afford six-membered nitrones. DFT calculations on four possible pathways supported a stepwise formation of C−N and C−H bonds, in which a 1,3-acyloxy-migration competes with the 1,3-azaprotio-transfer, especially in the case of internal alkynyl oximes. The relative nucleophilic properties of oxygen in the carbonyl group and the nitrogen in the oxime, the electronic effects of alkynes, and the influence of the ring system have been investigated computationally. 相似文献
4.
SungYong Seo Dr. Tobin J. Marks Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(17):5148-5162
Lanthanide‐organic complexes of the general type [Ln{N(SiMe3)2}3] (Ln=La, Sm, Y, Lu) serve as effective precatalysts for the rapid, exo‐selective, and highly regioselective tandem double intramolecular hydroalkoxylation/cyclization of primary and secondary dialkynyl dialcohols to yield the corresponding bi‐exocyclic enol ethers. Conversions are highly selective with products distinctly different from those generally produced by conventional transition metal or other catalysts, and the turnover frequencies with some substrates are too large to determine accurately. The rates of terminal alkynl alcohol hydroalkoxylation/cyclization are significantly more rapid than those of internal alkynyl alcohols, arguing that steric demands dominate the cyclization transition state. The hydroalkoxylation/cyclizations of internal dialkynyl dialcohols afford excellent E selectivity. The rate law for dialkynyl dialcohol hydroalkoxylation/cyclization is first‐order in [catalyst] and zero‐order in [alkynyl alcohol], as is observed for the organolanthanide‐catalyzed hydroamination/cyclization of aminoalkenes, aminoalkynes, and aminoallenes, and the intramolecular single‐step hydroalkoxylation/cyclization of alkynyl alcohols. An ROH/ROD kinetic isotope effect of 0.82(0.02) is observed for the tandem double hydroalkoxylation/cyclization. These mechanistic data implicate turnover‐limiting insertion of C? C unsaturation into the Ln? O bond, involving a highly organized transition state, with subsequent, rapid Ln–C protonolysis. 相似文献
5.
Charlotte Po Zhihai Ke Dr. Anthony Yiu‐Yan Tam Prof. Dr. Hak‐Fun Chow Prof. Dr. Vivian Wing‐Wah Yam 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(46):15735-15744
A series of platinum(II) terpyridine complexes with L ‐valine‐modified alkynyl ligands has been synthesized. A complex with an unsubstituted terpyridine and one valine unit on the alkynyl is shown to be capable of gel formation, which is in sharp contrast to the gelation properties of the corresponding organic counterparts. Upon sol–gel transition, a drastic color change from yellow to red is observed, which is indicative of the involvement of Pt ??? Pt interactions. Through the concentration‐ and temperature‐dependent UV/Vis absorption, emission, circular dichroism, and 1H NMR studies, the contribution of hydrogen bonding, Pt ??? Pt and π–π stacking interactions as driving forces for gelation have been established, and the importance of maintaining a delicate balance between different intermolecular forces has also been illustrated. 相似文献
6.
Yingnan Cao Haoyan Fang Chaofei Guo Weiwei Sun Yi Xu Yang Wu Yong Wang 《Angewandte Chemie (International ed. in English)》2023,62(30):e202302143
The poor conductivity of the pristine bulk covalent organic material is the main challenge for its application in energy storage. The mechanism of symmetric alkynyl bonds (C≡C) in covalent organic materials for lithium storage is still rarely reported. Herein, a nanosized (≈80 nm) alkynyl-linked covalent phenanthroline framework (Alkynyl-CPF) is synthesized for the first time to improve the intrinsic charge conductivity and the insolubility of the covalent organic material in lithium-ion batteries. Because of the high degree of electron conjugation along alkynyl units and N atoms from phenanthroline groups, the Alkynyl-CPF electrodes with the lowest HOMO–LUMO energy gap (ΔE=2.629 eV) show improved intrinsic conductivity by density functional theory (DFT) calculations. As a result, the pristine Alkynyl-CPF electrode delivers superior cycling performance with a large reversible capacity and outstanding rate properties (1068.0 mAh g−1 after 300 cycles at 100 mA g−1 and 410.5 mAh g−1 after 700 cycles at 1000 mA g−1). Moreover, by Raman, FT-IR, XPS, EIS, and theoretical simulations, the energy-storage mechanism of C≡C units and phenanthroline groups in the Alkynyl-CPF electrode has been investigated. This work provides new strategies and insights for the design and mechanism investigation of covalent organic materials in electrochemical energy storage. 相似文献
7.
Fei-Hu Yu Xiu-Fang Song Guan-Hao Liu Dr. Xiaoyong Chang Dr. Kai Li Prof. Dr. Ying Wang Prof. Dr. Ganglong Cui Prof. Dr. Yong Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(67):e202202439
Two-coordinate donor-metal-acceptor type coinage metal complexes displaying efficient thermally activated delayed fluorescence (TADF) have been unveiled to be highly appealing candidates as emitters for organic light-emitting diodes (OLEDs). Herein a series of green to yellow TADF gold(I) complexes with alkynyl ligands has been developed for the first time. The complexes exhibit high photoluminescence quantum yields (PLQYs) of up to 0.76 in doped films (5 wt % in PMMA) at room temperature. The modifications of alkynyl ligands with electron-donating amino groups together with the use of electron-deficient carbene ligands induce ligand-to-ligand charge transfer excited states that give rise to TADF emission. Spectroscopic and density functional theory (DFT) calculations reveal the roles of electron-donating capability of the alkynyl ligand in tuning the excited-state properties. Solution-processed organic light-emitting diodes (OLEDs) using the present complexes as emitters achieve maximum external quantum efficiency (EQE) of up to 20 %. 相似文献
8.
Xiao‐Jiao Li Fang‐Zhi Peng Xiang Li Wen‐Tao Wu Zhong‐Wen Sun Ying‐Mei Li Shao‐Xiong Zhang Prof. Dr. Zhi‐Hui Shao 《化学:亚洲杂志》2011,6(1):220-225
The first catalytic asymmetric conjugate addition of 1,3‐dicarbonyl compounds to nitroenynes catalyzed by cinchona alkaloid‐based thiourea organocatalysts has been developed. The 1,4‐addition adducts were obtained solely, in moderate to good yields (up to 93 %) with good enantioselectivities (up to 99 % ee). This protocol affords a conceptually different entry to the precursors of pharmaceutically important chiral β‐alkynyl acid derivatives and synthetically useful chiral nitroalkynes. Notably, the protocol worked well with both aryl‐ and alkyl‐substituted alkynyl substrates. 相似文献
9.
Li-Long Dang Ting-Ting Li Ting-Ting Zhang Ying Zhao Tian Chen Xiang Gao Lu-Fang Ma Guo-Xin Jin 《Chemical science》2022,13(18):5130
Although the selective synthesis of complicated supramolecular architectures has seen significant progress in recent years, the exploration of the properties of these complexes remains a fascinating challenge. Herein, a series of new supramolecular topologies, metalla[2]catenanes and Borromean ring assemblies, were constructed based on appropriate Cp*Rh building blocks and two rigid alkynyl pyridine ligands (L1, L2) via coordination-driven self-assembly. Interestingly, minor differences between the two rigid alkynyl pyridine ligands with/without organic substituents led to products with dramatically different topologies. Careful structural analysis showed that π–π stacking interactions play a crucial role in stabilizing these [2]catenanes and Borromean ring assemblies, while also promoting nonradiative transitions and triggering photothermal conversion in both the solution and the solid states. These results were showcased through comparative studies of the NIR photothermal conversion efficiencies of the Borromean ring assemblies, [2]catenanes and metallarectangles, which exhibited a wide range of photothermal conversion efficiencies (12.64–72.21%). The influence of the different Cp*Rh building blocks on the NIR photothermal conversion efficiencies of their assemblies was investigated. Good photothermal conversion properties of the assemblies were also found in the solid state. This study provides a new strategy to construct valuable half-sandwich-based NIR photothermal conversion materials while also providing promising candidates for the further development of materials science.The selective synthesis of three kinds of supermolecular topologies, molecular Borromean ring, [2]catenane and metallarectangle based on two alkynyl ligands is presented. Remarkably, the NIR photothermal conversion efficiency was found to improve as the π–π stacking increases. 相似文献
10.
Cheng Sheng Dr. Zheng Ling Dr. Tanveer Ahmad Prof. Dr. Fang Xie Prof. Dr. Wanbin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(23):e202200128
Regioselective [3+3] annulation of alkynyl ketimines with α-cyano ketones for the synthesis of polysubstituted 4H-pyran derivatives with a quaternary CF3-containing center has been realized by using Cu(OAc)2 as the catalyst. The novel strategy tolerates a wide range of α-CF3 alkynyl ketimines and α-cyano ketones with both aryl and alkyl substitutents. A preliminary asymmetric synthesis of chiral product 3 has been attempted by using copper and chiral thiourea as the cocatalyst with excellent yields (86-99 %) and good enantioselectivities (71–78 % ee). Furthermore, product 3 aa could be obtained on a gram-scale reaction with 75 % yield and 99 % ee after recrystallization. Several products were also transformed readily. Control experiments indicate that the reaction involves a process with a base-catalyzed or chiral thiourea-catalyzed Mannich-type reaction followed by a highly regioselective copper-catalyzed ring-closing reaction on the alkynyl moiety in a 6-endo-dig fashion. 相似文献
11.
Trofimov A Chernyak N Gevorgyan V 《Journal of the American Chemical Society》2008,130(41):13538-13539
It was demonstrated that alkynyl halides could serve as a source of Br+ and acetylide ions in the same transformation. This allowed for the efficient one-step preparation of alkynyl epoxides, important organic building blocks, from readily available starting materials. 相似文献
12.
Daria V. Vorobyeva Tamara P. Vasilyeva Grigory T. Shchetnikov Gerd-V. Röschenthaler 《Journal of fluorine chemistry》2010,131(3):378-877
A convenient method for the preparation of α-CF3-α-aminophosphonates bearing alkynyl group at the α-carbon atom has been described. New alkynylphosphonates have been further utilized in the synthesis of functionalized triazole-containing α-CF3-α-aminophosphonates via copper-catalyzed (3+2)-cycloaddition to different organic azides. 相似文献
13.
Chen He Ban‐Kun Jin Wei‐Dong He Xue‐Song Ge Jing Tao Jing Yang Sheng‐Qi Chen 《Journal of polymer science. Part A, Polymer chemistry》2013,51(10):2142-2149
Long‐subchain hyperbranched polystyrene (lsc‐hp PSt) with uniform subchain length was obtained through copper‐catalyzed azide‐alkyne cycloaddition click chemistry from seesaw macromonomer of PSt having one alkynyl group anchored at the chain centre and two azido group attached to both chain ends [alkynyl‐(PSt‐N3)2]. After precipitation fraction, different portions of lsc‐hp PSt having narrow overall molecular weight distribution were obtained for further grafting with alkynyl‐capped poly(N‐isopropylacrylamide) (alkynyl‐PNIPAM), which was obtained via single‐electron transfer living radical polymerization of NIPAM with propargyl 2‐bromoisobutyrate as the initiator and grafted onto the peripheral azido groups of lsc‐hp PSt via click chemistry. Thus, amphiphilic lsc‐hp PSt grafted with PNIPAM chains (lsc‐hp PSt‐g‐PNIPAM) was obtained and would have star‐like conformation in tetrahydrofuran (THF). By replacing THF with water, lsc‐hp PSt‐g‐PNIPAM was dissolved at molecular level in aqueous solution due to the hydrophilicity of PNIPAM and exhibited thermal induced shrinkage of PNIPAM arms. The water‐insoluble lsc‐hp PSt would collapse densely and could be served as a reservoir to absorb hydrophobic chemicals in aqueous solution. The influence of overall molecular weight of lsc‐hp PSt on the absorption of pyrene was studied. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
14.
Highly E‐Selective and Enantioselective Michael Addition to Electron‐Deficient Internal Alkynes Under Chiral Iminophosphorane Catalysis 下载免费PDF全文
Dr. Daisuke Uraguchi Kohei Yamada Prof. Dr. Takashi Ooi 《Angewandte Chemie (International ed. in English)》2015,54(34):9954-9957
A highly E‐selective and enantioselective conjugate addition of 2‐benzyloxythiazol‐5(4H)‐ones to β‐substituted alkynyl N‐acyl pyrazoles is achieved under the catalysis of a P‐spiro chiral iminophosphorane. Simultaneous control of the newly generated central chirality and olefin geometry is possible with a wide array of the alkynyl Michael acceptors possessing different aromatic and aliphatic β‐substituents, as well as the various α‐amino acid‐derived thiazolone nucleophiles. This protocol provides access to structurally diverse, optically active α‐amino acids bearing a geometrically defined trisubstituted olefinic component at the α‐position. 相似文献
15.
Prof. Dr. Jianxiao Li Yougui Luo Lihua Hu Lele Liu Prof. Dr. Yin-Long Lai Wenfang Xiong 《European journal of organic chemistry》2023,26(7):e202201387
An N-heterocyclic carbene palladium (NHC-palladium)-catalyzed cascade annulation of alkynoic acids with unactivated alkenes under an oxygen atmosphere in ionic liquids is described. This protocol enables facile access for the preparation of diverse alkyl substituted α-methylene-γ-lactones in moderate to good yields with excellent Z/E selectivity. Moreover, the ionic liquid not only acts as the green solvent, but also as the eco-friendly chlorine source, thus avoiding the use of excess metal halides such as cupric chloride. Some preliminary mechanistic studies were performed, which further revealed possible pathways for this cascade annulation. 相似文献
16.
Elena Michel Fabian F. Grieser Alexandra V. Mackenroth Michael Schukin Petra Krämer Shaista Tahir Dr. Frank Rominger Dr. Matthias Rudolph Prof. Dr. A. Stephen K. Hashmi 《Angewandte Chemie (International ed. in English)》2023,62(42):e202309274
The chemistry of alkynyl triazenes is an emerging field for organic chemists and especially acid-induced nucleophilic functionalizations, either directly, or after a prior reaction towards aromatic triazenes under extrusion of nitrogen, paved the way for fruitful strategies. In contrast, the chemical behavior of alkynyl triazenes upon irradiation with light is still unknown. Herein we present the first photoactivation of alkynyl triazenes that triggers an uncommon reactivity pattern involving the cleavage of the N1−N2 bond of the triazene moiety resulting in a unique approach to cyanocarbenes from a readily available, stable, and insensitive precursor. This allows to access various nitrile compounds without the use of a toxic cyanating agent by exploiting the reactivity pattern of carbenes. By variation of the reaction conditions and light sources, different substitution patterns can be obtained selectively in good yields under mild and metal-free conditions, thus introducing the alkynyl triazene unit as a photo accessible methylene nitrile synthon. Using this synthon, subclasses like α-alkoxynitriles, α-aminonitriles and α-cyanohydrazones become easily available. These exhibit synthetically valuable substitution patterns for the synthesis of pharmaceuticals, intermediates for total synthesis and amino acid synthesis. 相似文献
17.
Dr. Shang-Fu Yuan Wen-Di Liu Dr. Chun-Yu Liu Dr. Zong-Jie Guan Prof. Dr. Quan-Ming Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(24):e202104445
Surface organic ligands are critical in dictating the structures and properties of atomically precise metal nanoclusters. In contrast to the conventionally used thiolate, phosphine and alkynyl ligands, nitrogen donor ligands have not been used in the protection for well-defined metal nanoclusters until recently. This review focuses on recent developments in atomically precise metal nanoclusters stabilized by different types of nitrogen donor ligands, in which the synthesis, total structure determination and various properties are covered. We hope that this review will provide insights into the rational design of N donor-protected metal nanoclusters in terms of structural and functional modulation. 相似文献
18.
Ag(I) and Au(I) efficiently catalyze the cycloisomerization of terminal alkynoic acids into methylene seven-membered ring lactones. Depending on the metal, divergent reaction pathways were found for non terminal alkynoic acids. While Ag(I) led to lactones, Au(I) led to 2H-chromenes coming from the hydroarylation of the alkyne. 相似文献
19.
A Substrate‐Based Approach to Skeletal Diversity from Dicobalt Hexacarbonyl (C1)‐Alkynyl Glycals by Exploiting Its Combined Ferrier–Nicholas Reactivity 下载免费PDF全文
Dr. Fernando Lobo Dr. Ana M. Gómez Silvia Miranda Prof. Dr. J. Cristóbal López 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(33):10492-10502
Novel substrates that combine dicobalt hexacarbonyl propargyl (Nicholas) and pyranose‐derived allylic (Ferrier) cations have been generated by treatment of hexacarbonyldicobalt (C‐1)‐alkynyl glycals with BF3.Et2O. The study of these cations has resulted in the discovery of novel reaction pathways that have shown to be associated to the nature of O‐6 substituent in the starting alkynyl glycals. Accordingly, compounds resulting from ring expansion (oxepanes), ring contraction (tetrahydrofurans), or branched pyranoses, by incorporation of nucleophiles, can be obtained from 6‐O‐benzyl, 6‐hydroxy, or 6‐O‐silyl derivatives, respectively. The use of a 6‐O‐allyl alkynyl glycal led to a suitable funtionalized oxepane able to experience an intramolecular Pauson–Khand cyclization leading to a single tricyclic derivative. 相似文献
20.
Ishfaq Ibni Hashim Nikolaos V. Tzouras Wim Janssens Dr. Thomas Scattolin Laurens Bourda Dr. Subhrajyoti Bhandary Prof. Dr. Kristof Van Hecke Prof. Dr. Steven P. Nolan Prof. Dr. Catherine S. J. Cazin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(47):e202201224
A straightforward synthetic protocol leading to carbene–metal–amido (CMA) complexes (metal=Au, Cu) using a mild base and an environmentally desirable solvent (EtOH) has been explored, with a focus on complexes bearing backbone-substituted N-heterocyclic carbene (NHC) ligands, including BIAN-NHCs (BIAN=bis(imino)acenaphthene). The novel CMAs were structurally characterized, and gold-based CMAs bearing diverse NHCs were screened as simple, Brønsted-basic precatalysts. The readily accessible complexes display high catalytic activity in the intermolecular and intramolecular hydrocarboxylation of internal alkynes and alkynoic acids respectively, while the screening reveals the ancillary ligand effect of NHCs in these catalytic systems. 相似文献