- In the optically-multiplexed-
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A method for optical super-multiplexing using polyynes to provide enhanced images from stimulated Raman microscopy is disclosed. In some exemplary embodiments, the polyynes are organelle-targeted or spectral barcoded. Imaging can be enhanced by using the polyynes to image whole live cells or specific organelles within live cells. The polyynes can also be used in optical data storage (i.e., encoding) and identification (i.e., decoding) applications.
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Paragraph 0216; 0217
(2020/12/30)
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- Regio- and Stereoselective Synthesis of 1,2-Dihaloalkenes Using In-Situ-Generated ICl, IBr, BrCl, I2, and Br2
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We describe a catalyst-free 1,2-trans-dihalogenation of alkynes with an unprecedented substrate scope and exclusive regio- and stereoselectivity. This versatile dihalogenation system—a combination of NX1S electrophile and alkali metal halide (MX2) in acetic acid—is applicable for diverse categories of alkynes (electron-rich or poor alkynes, internal and terminal alkynes, or heteroatoms such as O-, N-, S-substituted alkynes). The hydrogen bonding donor solvent acetic acid is essential for the in-situ generation of X1X2 electrophile, including ICl, IBr, BrCl, I2, and Br2. Haloalkenes are not only commonly found in biologically active natural products but also have been used extensively in cross-coupling reactions. More specifically, 1,2-dihaloalkenes are especially important synthons because of the presence of two synthetic handles that open a broad avenue to expeditiously generate multisubstituted alkenes. Dihalogenation of alkynes is a straightforward way to prepare 1,2-dihaloalkenes. However, existing alkyne dihalogenation methods either rely on the use of toxic reagents, such as IBr and ICl, lack regio- and stereoselectivity or have limited substrate scope. Thus, the development of a widely applicable and yet efficient alkyne dihalogenation method is still highly desired. Here, we have addressed the aforementioned issues based on an in-situ-generated dihalogenation of reagents, such as ICl and Ibr, by using the readily available N-halosuccinimide (NXS) and alkali metal halides as halogen sources. Our method offers an unprecedented substrate scope, the regio- and stereoselectivity for the synthesis of 1,2-dihaloalkenes. Our simple and mild conditions might find wild applications in the preparation of high-value building blocks for medicines and materials. Dihaloalkenes are important raw materials for pharmaceutical and chemical industries. However, existing preparation methods suffer from a limited substrate scope as well as poor regio- and stereoselectivity. Furthermore, these methods often necessitate highly toxic reagents, such as Cl2, ICl, and BrCl. Our environmentally friendly 1,2-trans-dihalogenation is based on easy-handling halide sources, such as alkali metal halides. What is more, our method offers an unprecedented substrate scope, the regio- and stereoselectivity for the synthesis of 1,2-dihaloalkenes.
- Hammond, Gerald B.,Liu, Shiwen,Xu, Bo,Yang, Yi,Yang, Yuhao,Zeng, Xiaojun
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supporting information
p. 1018 - 1031
(2020/04/08)
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- Stereoselective Synthesis of Highly Substituted Conjugated Dienes via Pd-Catalyzed Carbonylation of 1,3-Diynes
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The stereoselective synthesis of conjugated dienes was realized for the first time via Pd-catalyzed alkoxycarbonylation of easily available 1,3-diynes. Key to success is the utilization of the specific ligand 1,1′-ferrocenediyl-bis(tert-butyl(pyridin-2-yl)phosphine) (L1), which allows this novel transformation to proceed at room temperature. A range of 1,2,3,4-tetrasubstituted conjugated dienes are obtained in this straightforward access in high yields and selectivities. The synthetic utility of the protocol is showcased in the concise synthesis of several important intermediates for construction of natural products rac-cagayanin, rac-galbulin, rac-agastinol, and cannabisin G.
- Liu, Jiawang,Yang, Ji,Baumann, Wolfgang,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 10683 - 10687
(2019/07/04)
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- Selective Hydroarylation of 1,3-Diynes Using a Dimeric Manganese Catalyst: Modular Synthesis of Z-Enynes
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The transition-metal-catalyzed selective hydroarylation of unsymmetrical alkynes represents the state-of-art in organic chemistry, and still mainly relies on the use of precious late-transition-metal catalysts. Reported herein is an unprecedented MnI-catalyzed hydroarylation of unsymmetrical 1,3-diyne alcohols with commercially available arylboronic acids with predictive selectivity. This method addresses the challenges in regio-, stereo-, and chemoselectivity. It offers a general, convenient and practical strategy for the modular synthesis of multisubstituted Z-configurated conjugated enynes. This protocol is distinguished by its operational simplicity, complete selectivity, excellent functional-group compatibility, and gram-scale potential. A dimeric MnI species, Mn2(CO)8Br2, was proven to be a much more efficient catalyst precursor than Mn(CO)5Br.
- Yan, Zhongfei,Yuan, Xiang-Ai,Zhao, Yue,Zhu, Chengjian,Xie, Jin
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supporting information
p. 12906 - 12910
(2018/09/25)
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- An efficient heterogeneous palladium(0)-catalysed cross-coupling between 1-bromoalkynes and terminal alkynes leading to unsymmetrical 1,3-diynes
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An efficient heterogeneous palladium(0)-catalysed cross-coupling of 1-bromoalkynes with terminal alkynes was achieved in DMF at room temperature in the presence of 5 mol% of MCM-41-immobilised bidentate phosphine palladium(0) complex [MCM-41-2P-Pd(0)] and 2 mol% of CuI with Et3N as base, yielding a variety of unsymmetrical 1,3-diynes in moderate to good yields. This heterogeneous palladium(0) complex could be easily recovered by a simple filtration of the reaction solution and recycled at least seven times without significant decrease in activity.
- Xu, Zhaotao,Ai, Jinting,Cai, Mingzhong
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p. 133 - 137
(2018/04/20)
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- Glaser-Hay hetero-coupling in a bimetallic regime: A Ni(II)/Ag(i) assisted base, ligand and additive free route to selective unsymmetrical 1,3-diynes
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A Ni(OAc)2/Ag(OTf) catalysed coupling of aryl alkynes and propargylic alcohol/ether/ester gave the corresponding unsymmetrical 1,3-diynes in good to excellent yields. The reaction does not require bases, ligands or additives and shows excellent hetero-selectivity, thereby addressing the current challenges in the field of coupling of two different terminal alkynes.
- Mohanty, Anuradha,Roy, Sujit
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supporting information
p. 10796 - 10799
(2017/10/06)
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- Magnetic copper ferrite catalyzed homo- and cross-coupling reaction of terminal alkynes under ambient atmosphere
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The application of non-toxic and magnetically separable nano-CuFe2O4 as an efficient catalyst for oxidative homo- and cross-coupling reaction of terminal alkynes is described. A wide range of symmetrical and unsymmetrical 1,3-diynes have been synthesized in moderate to good yields under ambient atmosphere. The nano CuFe2O4 can be recovered with a magnet and reused at least five consecutive cycles with no appreciable loss of its catalytic activity.
- Ma, Cui-Ting,Wang, Jiao-Jiao,Zhao, Ai-Dong,Wang, Qing-Li,Zhang, Zhan-Hui
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- Visible-light-activated copper(i) catalyzed oxidative Csp-Csp cross-coupling reaction: Efficient synthesis of unsymmetrical conjugated diynes without ligands and base
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A novel visible-light-promoted copper-catalysed process for the Csp-Csp cross-coupling reaction of terminal alkynes at room temperature is described. The current photochemical method is simple, highly functional group compatible, and more viable towards the construction of bio-active 1,3-unsymmetrical conjugated diynes without the need of bases/ligands, additives and expensive palladium/gold catalysts.
- Sagadevan, Arunachalam,Lyu, Ping-Chiang,Hwang, Kuo Chu
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supporting information
p. 4526 - 4530
(2016/08/18)
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- Palladium supported on amine-functionalized mesoporous silica: Highly efficient phosphine-free catalyst for alkyne-alkyne cross-coupling reaction
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An amine-functionalized mesoporous silica SBA-15 supported palladium catalyst was prepared and characterized. For the first time, this supported palladium has been used as an efficient phosphine-free and reusable catalyst for the cross-coupling of haloalkynes with terminal alkynes. A variety of haloalkynes and aromatic/aliphatic terminal alkynes were selectively coupled to afford unsymmetrical 1,4-disubstituted 1,3-diynes in good yields.
- Li, Hongling,Wang, Lailai,Yang, Min,Qi, Yanxing
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experimental part
p. 179 - 183
(2012/02/16)
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- Efficient copper(II) acetate catalyzed homo- and heterocoupling of terminal alkynes at ambient conditions
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Symmetrical 1,3-diynes were obtained in quantitative yields using the copper(II) acetate catalyzed homocoupling of terminal alkynes in the presence of a stoichiometric amount of piperidine at 25 °C under aerobic conditions. We also accomplished facile syntheses of unsymmetric 1,3-diynes by heterocoupling terminal alkynes in very good yields under the reported reaction conditions. Georg Thieme Verlag Stuttgart.
- Balaraman, Kaluvu,Kesavan, Venkitasamy
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experimental part
p. 3461 - 3466
(2010/11/21)
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- Copper-catalyzed cross-coupling reactions of bromoalkynols with terminal alkynes in supercritical carbon dioxide
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Copper-catalyzed cross-coupling reactions of bromoalkynols and terminal alkynes were carried out in supercritical carbon dioxide (scCO2) to afford the corresponding unsymmetrical diynes with good yields. The reaction is sensitive to temperature and the pressure of CO2. Methanol, as a cosolvent of scCO2, could promote dissolution of the inorganic salt and thus facilitated the reaction. This new heterocoupling reaction system is more environmentally friendly than more traditional methods, since it uses scCO2 as solvent and sodium acetate as base instead of amines. Georg Thieme Verlag Stuttgart.
- Jiang, Huan-Feng,Wang, A.-Zhong
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p. 1649 - 1654
(2008/02/05)
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- A convenient route to unsymmetrical conjugated diynes
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Various unsymmetrical conjugated diynes can be prepared in good to excellent isolated yields by copper catalyzed coupling reaction of terminal alkynes with 1-iodo alkynes in pyrrolidine. In the case of 1-bromo alkynes, the presence of a catalytic amount o
- Alami, Mouad,Ferri, Fabiola
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p. 2763 - 2766
(2007/10/03)
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