- Expanded Cyclotetrabenzoins
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Cyclobenzoins are shape-persistent macrocycles of interest in the preparation of optoelectronic and porous materials. New cyclotetrabenzoins derived from biphenyl, naphthalene, and tolane skeletons were synthesized using N-heterocyclic carbene-catalyzed b
- Eisterhold, Andrew M.,Puangsamlee, Thamon,Otterbach, Steffen,Br?se, Stefan,Weis, Patrick,Wang, Xiqu,Kutonova, Ksenia V.,Miljani?, Ognjen ?.
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p. 781 - 785
(2021/01/26)
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- Robust Alkyne Metathesis Catalyzed by Air Stable d2Re(V) Alkylidyne Complexes
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We report in this communication the first example of catalytic alkyne metathesis reactions mediated by well-defined non-d0 alkylidyne complexes. The air-stable d2 Re(V) alkylidyne complex Re4, bearing two PO-chelating ligands and a labile pyridine ligand, could catalyze homometathesis of internal alkynes with a broad substrate scope, including alcohols, amines, and even carboxylic acids. The catalyst can tolerate heating, air, and moisture in both solid and solution states, and the catalytic metathesis reactions could proceed normally in wet solvents.
- Cui, Mingxu,Bai, Wei,Sung, Herman H. Y.,Williams, Ian D.,Jia, Guochen
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supporting information
p. 13339 - 13344
(2020/09/03)
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- Reticular Synthesis of Multinary Covalent Organic Frameworks
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Hexagonal hexaminophenyl benzene, tetragonal tetrakis(4-aminophenyl) ethane, and trigonal 1,3,5-tris(p-formylphenyl)benzene were all joined together by imine linkages to yield a 2D porous covalent organic framework with unprecedented tth topology, termed
- Zhang, Bing,Mao, Haiyan,Matheu, Roc,Reimer, Jeffrey A.,Alshmimri, Sultan A.,Alshihri, Saeed,Yaghi, Omar M.
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p. 11420 - 11424
(2019/08/20)
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- Syntheses, Spectroscopic Properties, and Computational Study of (E, Z)-Ethenyl and Ethynyl-Linked BODIPYs
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A series of (E,Z)-ethenyl- and ethynyl-linked boron dipyrromethene (BODIPY) dimers were synthesized in 23-34% yields by condensation of pyrroles with the corresponding bis-benzaldehydes, followed by oxidation and boron complexation. The BODIPY dimers were characterized by 1H, 13C, and 11B NMR spectroscopy, high-resolution mass spectrometry, and, in the cases of 1b, 2, and 3, by X-ray crystallography. The spectroscopic properties for this series of dimers were investigated in tetrahydrofuran solutions, and very similar absorption and emission profiles were observed for all dimers. Density functional theory calculations show minimal conjugation between the two BODIPY units in the dimers, as a result of the large dihedral angle between the BODIPYs and the linker. The (E)-ethenyl-linked dimer 1a showed the highest fluorescence quantum yield of all dimers investigated in this study.
- Zhang, Guanyu,Zhao, Ning,Bobadova-Parvanova, Petia,Wang, Maodie,Fronczek, Frank R.,Smith, Kevin M.,Vicente, M. Gra?a H.
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p. 6256 - 6265
(2018/07/15)
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- Synthesis of α,α-Dichloroketones through Sequential Reaction of Decarboxylative Coupling and Chlorination
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2,2-Dichloro-1,2-diarylethanones were synthesized from diarylalkynes and trichloroisocyanuric acid. The reaction was conducted in CH3CN/H2O at room temperature for 12 h. In addition, the desired 2,2-dichloro-1,2-diarylethanones could be prepared from aryl bromides and propiolic acid through sequential Pd-catalyzed decarboxylative coupling and chlorination. This method showed moderate to good yields and good tolerance toward functional groups such as chlorides, bromides, aldehydes, and ketones.
- Cho, Eunjeong,Kim, Myungjin,Jayaraman, Aravindan,Kim, Jimin,Lee, Sunwoo
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supporting information
p. 781 - 784
(2018/02/21)
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- Synthesis of Phenalenyl-Fused Pyrylium Cations: Divergent C?H Activation/Annulation Reaction Sequence of Naphthalene Aldehydes with Alkynes
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Described herein is the synthesis of stable oxonium-doped polycyclic aromatic hydrocarbons (PAHs) by the rhodium-catalyzed C?H activation/annulations of naphthalene-type aldehydes with internal alkynes. This protocol provides four divergent reaction types, including two unexpected annulations with an oxygen transposition process, which lead to diverse types of phenalenyl-fused pyrylium cations comprising a four-, five-, or six-ring-fused π-conjugated core. The annulations exhibit an exquisite regioselectivity and a high tolerance of sensitive functional groups. These PAHs feature intriguing photophysical properties such as full-color tunable fluorescence emission, high quantum yield, and positively charged core, and can be reduced easily to the phenalenyl radicals.
- Yin, Jiangliang,Tan, Meiling,Wu, Di,Jiang, Ruyong,Li, Chengming,You, Jingsong
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p. 13094 - 13098
(2017/09/18)
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- Highly Active Multidentate Ligand-Based Alkyne Metathesis Catalysts
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Alkyne metathesis catalysts composed of molybdenum(VI) propylidyne and multidentate tris(2-hydroxylbenzyl)methane ligands have been developed, which exhibit excellent stability (remains active in solution for months at room temperature), high activity, an
- Du, Ya,Yang, Haishen,Zhu, Chengpu,Ortiz, Michael,Okochi, Kenji D.,Shoemaker, Richard,Jin, Yinghua,Zhang, Wei
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supporting information
p. 7959 - 7963
(2016/06/09)
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- An azine-linked hexaphenylbenzene based covalent organic framework
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In this communication, we report an azine linked covalent organic framework based on a six-fold symmetric hexphenylbenzene (HEX) monomer functionalized with aldehyde groups. HEX-COF 1 has an average pore size of 1 nm, a surface area in excess of 1200 msu
- Alahakoon, Sampath B.,Thompson, Christina M.,Nguyen, Amy X.,Occhialini, Gino,McCandless, Gregory T.,Smaldone, Ronald A.
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p. 2843 - 2845
(2016/02/19)
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- Synchronized Offset Stacking: A Concept for Growing Large-Domain and Highly Crystalline 2D Covalent Organic Frameworks
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Covalent organic frameworks (COFs), formed by reversible condensation of rigid organic building blocks, are crystalline and porous materials of great potential for catalysis and organic electronics. Particularly with a view of organic electronics, achievi
- Auras, Florian,Ascherl, Laura,Hakimioun, Amir H.,Margraf, Johannes T.,Hanusch, Fabian C.,Reuter, Stephan,Bessinger, Derya,D?blinger, Markus,Hettstedt, Christina,Karaghiosoff, Konstantin,Herbert, Simon,Knochel, Paul,Clark, Timothy,Bein, Thomas
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p. 16703 - 16710
(2017/01/10)
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- Interacting networks of purely organic spin-1/2 dimers
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In the present study we report the synthesis of some novel nitronyl nitroxide biradical systems 1-4c with various π-bridges between the radical centres. UV-Vis, IR, EPR and X-ray diffraction studies, along with MS and NMR data where appropriate, are described. Magnetic measurements revealed that the biradicals 1c, 3c and 4c exhibit a moderately strong antiferromagnetic intra-molecular exchange, whereas nitroxide 2c shows a significantly higher exchange coupling, which can only be explained by the presence of strong inter-molecular interactions. From DFT calculations performed on the basis of the X-ray crystal structure of compound 4c, a theoretical value of the intra-dimer coupling constant Jintra = -8.6 K is obtained. Direct proof also for inter-molecular arrangement with Jinter ~ -2 K was provided by the low temperature AC studies of biradical 4c. According to the magnetic characterization, the nitronyl biradical 4c is a promising candidate for a purely organic-based low-dimensional quantum magnet. This journal is the Partner Organisations 2014.
- Borozdina, Yulia B.,Mostovich, Evgeny,Enkelmann, Volker,Wolf, Bernd,Cong, Pham T.,Tutsch, Ulrich,Lang, Michael,Baumgarten, Martin
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p. 6618 - 6629
(2014/08/18)
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- Multidentate triphenolsilane-based alkyne metathesis catalysts
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A series of triphenolsilane-coordinated molybdenum(VI) propylidyne catalysts has been developed, which are resistant to small alkyne polymerization and compatible with various functional groups (including phenol substrates). The catalysts remain active in
- Yang, Haishen,Liu, Zhenning,Zhang, Wei
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supporting information
p. 885 - 890
(2013/05/08)
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- Highly Active Multidentate Catalysts for Efficient Alkyne Metathesis
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The invention relates to highly active and selective catalysts for alkyne metathesis. In one aspect, the invention includes a multidentate organic ligand wherein one substrate-binding site of the metal center is blocked. In another aspect, the invention includes N-quaternized or silane-based multidentate organic ligands, capable of binding to metals. In yet another aspect, the invention includes N-quaternized or silane-based multidentate catalysts. The catalysts of the invention show high robustness, strong resistance to small alkyne polymerization and significantly enhanced catalytic activity compared to their corresponding non-quaternized or non-silane-based multidentate catalyst analogues.
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Paragraph 0281; 0282
(2013/10/08)
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- Highly active multidentate alkyne metathesis catalysts: Ligand-activity relationship and their applications in efficient synthesis of porphyrin-based aryleneethynylene polymers
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A series of tris(arylmethyl)ammonium-coordinated molybdenum(VI) propylidyne catalysts was synthesized. Such N-quarternized multidentate catalysts showed high robustness, strong resistance to small alkyne polymerization and significantly enhanced catalytic activity compared to their corresponding tris(arylmethyl)amine-based analogues. The high activity of these new catalysts also enabled the efficient synthesis of ethynylene-bridged porphyrin-based arylene ethynylene polymers via alkyne metathesis, which represents a highly efficient, defect-free, viable approach for the synthesis of this class of intriguing polymers. Copyright
- Jyothish, Kuthanapillil,Wang, Qi,Zhang, Wei
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supporting information
p. 2073 - 2078,6
(2020/09/02)
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- Calcium carbide as a cost-effective starting material for symmetrical diarylethynes via Pd-catalyzed coupling reaction
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A convenient and cost-effective synthetic method for symmetrical diarylethynes from inexpensive calcium carbide and aryl iodide has been developed. The reaction not only proceeds with high yield and selectivity but also tolerates a wide range of functional groups. Application of this reaction has enabled the synthesis of highly functionalized oligo (phenyleneethynylenes) to be accomplished.
- Chuentragool, Padon,Vongnam, Kunnigar,Rashatasakhon, Paitoon,Sukwattanasinitt, Mongkol,Wacharasindhu, Sumrit
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experimental part
p. 8177 - 8182
(2011/10/31)
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- Introducing a podand motif to alkyne metathesis catalyst design: A highly active multidentate molybdenum(VI) catalyst that resists alkyne polymerization
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Podand prevents polymers: The molybdenum(VI) propylidyne catalyst 1 with a podand triphenolamine ligand shows high activity in the metathesis of a variety of alkyne substrates, including heterocycles that contain donor moieties. With one substrate-binding site blocked by the multidentate ligand, the undesired polymerization of small alkynes that occurs with non-podand-ligand complex 2 is completely inhibited. Copyright
- Jyothish, Kuthanapillil,Zhang, Wei
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supporting information; experimental part
p. 3435 - 3438
(2011/05/04)
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- Synthesis of symmetrical and unsymmetrical diarylalkynes from propiolic acid using palladium-catalyzed decarboxylative coupling
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Figure presented. Symmetrical diarylalkynes were obtained from propiolic acid (or 2-butynedioic acid) and aryl halides in good yields. The optimized reaction conditions were 2.0 equiv of aryl halide, 1.0 equiv of propiolic acid, 5.0 mol % Pd(PPh3/su
- Park, Kyungho,Bae, Goun,Moon, Jeongju,Choe, Jaehoon,Song, Kwang Ho,Lee, Sunwoo
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experimental part
p. 6244 - 6251
(2010/12/20)
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- Optimization of the central linker of dicationic bis-benzimidazole anti-MRSA and anti-VRE agents
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A series of bis-benzimidazole diamidine compounds containing different central linkers has been synthesized and evaluated for in vitro antibacterial activities, including drug-resistant bacterial strains. Seven compounds have shown potent antibacterial activities. The anti-MRSA and anti-VRE activities of compound 1h were more potent than that of the lead compound 1a and vancomycin.
- Hu, Laixing,Kully, Maureen L.,Boykin, David W.,Abood, Norman
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scheme or table
p. 3374 - 3377
(2010/02/28)
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- The use of calcium carbide in one-pot synthesis of symmetric diaryl ethynes
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An efficient Pd-catalyzed copper and amine free coupling reaction of acetylene and aryl bromides was achieved with calcium carbide as an acetylene source, using inorganic base and easily prepared, air-stable aminophosphine ligand in common organic solvents, providing symmetric diaryl ethynes in one-pot with yields ranged from moderate to excellent. The Royal Society of Chemistry 2006.
- Zhang, Weiwei,Wu, Huayue,Liu, Zhiqing,Zhong, Ping,Zhang, Lin,Huang, Xiaobo,Cheng, Jiang
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p. 4826 - 4828
(2007/10/03)
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- Double elimination protocol for the synthesis of arylene ethynylenes containing heteroaromatic rings
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The double elimination reaction of β-substituted sulfones offers a versatile strategy for synthesis of arylene ethynylene kits containing heteroaromatic rings. A sequence of aldol reaction between α-sulfonyl carbanion and aldehyde, trapping the resulting aldolate to give β-substituted sulfone, and double elimination of this intermediate can be integrated in one pot. This protocol allows thiophene, pyridine, and ferrocene units to be accommodated in phenylene ethynylene arrays.
- Orita, Akihiro,Ye, Fangguo,Babu, Govindarajulu,Ikemoto, Tomohiro,Otera, Junzo
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p. 716 - 727
(2007/10/03)
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- Highly Active Trialkoxymolybdenum(VI) Alkylidyne Catalysts Synthesized by A Reductive Recycle Strategy
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A systematic study of alkyne metathesis catalyzed by trialkoxymolybdenum(VI) alkylidyne complexes is reported, in which substrate functional groups, alkynyl substituents, and catalyst ligands are varied. Sterically hindered trisamidomolybdenum(VI) propylidyne complex 5 was prepared conveniently through a previously communicated reductive recycle strategy. Alcoholysis of 5 with various phenols/alcohols provides a set of active catalysts for alkyne metathesis at room temperature, among which the catalyst with p-nitrophenol as ligand shows the highest catalytic activity and is compatible with a variety of functional groups and solvents. A key finding that enabled the use of highly active molybdenum(VI) catalysts is replacement of the commonly used propynyl substituents on the starting alkyne substrates with butynyl groups. Under reduced pressure using 1,2,4-trichlorobenzene as an involatile solvent, the alkyne metathesis of butynyl substituted compounds proceeds well at 30 °C providing high yields (83%-97%) of dimers. Rationalization of the special role played by butynyl substrates is discussed.
- Zhang, Wei,Kraft, Stefan,Moore, Jeffrey S.
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p. 329 - 335
(2007/10/03)
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- Alkyne metathesis: Development of a novel molybdenum-based catalyst system and its application to the total synthesis of epothilone A and C
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Sterically hindered molybdenum(III) amido complexes of the general type [Mo{(tBu)(Ar)N}3] (1), upon treatment with CH2Cl2 or other halogen donors, have been converted into highly effective catalysts for all kinds of alkyne metathesis reactions. Although the actual nature of the propagating species formed in situ is still elusive, halogen transfer to the Mo center of 1 plays a decisive role in the activation of such precatalysts. It was possible to isolate and characterize by X-ray crystallography some of the resulting molybdenum halide derivatives such as 15, 16 and 20 which themselves were shown to be catalytically active. Numerous applications illustrate the performance of the catalytic system 1/CH2Cl2 which operates under mild conditions and tolerates an array of polar functional groups. The wide scope allows the method to be implemented into the total synthesis of sensitive and polyfunctional natural products. Most notable among them is a concise entry into the potent anticancer agents epothilone A (86) and C (88). The macrolide core of these targets is forged by ring closing alkyne metathesis (RCAM) of diyne 113, followed by Lindlar hydrogenation of cycloalkyne 114 thus formed. Since this strategy opens a stereoselective entry into (Z)-alkene 115, the approach is inherently more efficient than previous syntheses based on conventional RCM. Wiley-VCH Verlag GmbH, 2001.
- Fuerstner, Alois,Mathes, Christian,Lehmann, Christian W.
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p. 5299 - 5317
(2007/10/03)
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- Alkyne cross metathesis reactions of extended scope
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equation presented A catalyst formed in situ from Mo[N(t-Bu)(Ar)]3 1 (Ar = 3,5-dimethylphenyl) and CH2Cl2 in toluene effects cross metathesis reactions of functionalized alkynes that are beyond reach of more traditional promotors. An application to the synthesis of prostaglandin E2 (PGE2) 19 and the acetylated PGE derivative 18b shows the compatibility of this method with sensitive substrates.
- Fuerstner, Alois,Mathes, Christian
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p. 221 - 223
(2007/10/03)
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