- Halo-1,2,3-triazolium salts as halogen bond donors for the activation of imines in dihydropyridinone synthesis
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In the past decade halogen bond (XB) catalysis has gained considerable attention. Halo-triazoles are known XB donors, yet few examples detail their use as catalysts. As a continuation of our previous work the catalytic properties of substituted enantiomerically pure halo-triazolium salts were explored in the reaction between an imine and Danishefsky's diene leading to the formation of dihydropyridinone. The catalytic activity of the XB donors was highly dependent on the choice of the halogen atom and on the counterion. Also, it was found that impurities in the diene affected the rate of the reaction.
- Kaasik, Mikk,Metsala, Andrus,Kaabel, Sandra,Kriis, Kadri,J?rving, Ivar,Kanger, Tonis
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p. 4295 - 4303
(2019/03/29)
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- Thieme chemistry journal awardees - Where are they now? Pentafluorophenyl end-capped polyynes as supramolecular building blocks
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The synthesis of pentafluorophenyl end-capped polyynes up to an octayne has been developed based on the use of a Fritsch-Buttenberg-Wiechell rearrangement as the key step. UV/Vis spectroscopic analysis shows little change in the electronic nature of these
- Tykwinski, Rik R.,Kendall, Jamie,McDonald, Robert
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experimental part
p. 2068 - 2075
(2011/03/20)
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- Arene-perfluoroarene interactions in crystal engineering: Structural preferences in polyfluorinated tolans
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The compounds 4-ROC6F4C≡Ph (4) where R = Me (a), Et (b), Prn (c), Pri (d), Bun (e), W-C5H11 (f), PhCH2 (g), PhCH2CH 2 (h), 4-MeC6Hsub
- Smith, Caroline E.,Smith, Philip S.,Thomas, Rhodri Ll.,Robins, Edward G.,Collings, Jonathan C.,Dai, Chaoyang,Scott, Andrew J.,Borwick, Simon,Batsanov, Andrei S.,Watt, Stephen W.,Clark, Stewart J.,Viney, Christopher,Howard, Judith A. K.,William, Clegg,Marder, Todd B.
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p. 413 - 420
(2007/10/03)
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- SYNTHESIS OF 1,4-BIS-(p-ARYLOXY-TETRAFLUOROPHENYL)BUTADIYNE MONOMERS FOR NONLINEAR OPTICS
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Novel diacetylenes with polyfluorophenyl groups directly bound to the diacetylene moiety, 1,4-bis(p-aryloxy-tetrafluorophenyl)butadiynes, were prepared in four steps from pentafluoroiodobenzene and trimethylsilylacetylene.
- Zhang, Yadong,Wen, Jianxun
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- A Convenient Synthesis of Bis(polyfluorophenyl)butadiyne Monomers
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1,4-Bis(polyfluorophenyl)butadiynes were prepared in high yields by nucleophilic substitutions on the 1,4-bis(pentafluorophenyl)butadiyne which was prepared in three steps from pentafluoroiodobenzene and trimethylsilylacetylene.
- Zhang, Yadong,Wen, Jianxun
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p. 727 - 728
(2007/10/02)
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- Synthesis of High Carbon Materials from Acetylenic Precursors. Preparation of Aromatic Monomers Bearing Multiple Ethynyl Groups
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The synthesis of polyethynyl aromatics as starting materials for the preparation of highly cross-linked organic solids containing high atom fractions of carbon is described.Treatment of bromo- and iodoaromatic compounds with (trimethylsilyl)acetylene (TMSA) in the presence of palladium(O) and copper(I) in amine solvents yields (trimethylsilyl)ethynyl-substituted aromatics.The TMS protecting groups can be removed by hydrolysis with mild base.Compounds prepared by using this technique include 1,3-diethynylbenzene, 2,5-diethynylthiophene, 1,3-diethynyltetrafluorobenzene, 1,4-diethynyltetrafluorobenzene, 2-ethynylthiazole, 2,4-diethynylthiazole, 2,7-diethynylnaphthalene, hexakis((trimethylsilyl)ethynyl)benzene, tetraethynylthiophene, 2,5-bis((trimethylsilyl)ethynyl)-3,4-bis(3-hydroxy-3-methyl-1-butynyl)thiophene, 2,5-diethynyl-3,4-bis(3-hydroxy-3-methyl-1-butynyl)thiophene, 2,5-bis(4-(2-thienyl)butadiynyl)-3,4-bis(3-hydroxy-3-methyl-1-butynyl)thiophene, and 2,5-bis-(4-(2-thienyl)butadiynyl)-3,4-diethynylthiophene.
- Neenan, Thomas X.,Whitesides, George M.
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p. 2489 - 2496
(2007/10/02)
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- Laser-Induced Reactions of Hexafluorobenzene and Selected Hydride Compounds
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Infrared-laser-induced reactions between C6F6 and general hydrides R-H (R = H, D, CH3, HCC, H2C=CH, and Cl) were studied by irradiating C6F6 at 1027 cm-1 in C6F6/R-H mixtures.In general, two competitive pathways involving C-F bond cleavage in C6F6 were observed as follows: (1) C6F6 + R-H C6F5H + R-F and (2) C6F6 + R-H C6F5R + HF.C6F6 decomposition also took place to a minor extent depending on the mole fraction of C6F6 and gave rise to C2F4 and C2H2.From infrared and GC/MS analysis of the product mixtures after 20-200 pulses, C6F5H was observed in all reactions except that involving D2.When D2 was used C6F5D was the major product.C6F5H was the major product in the reactions involving H2 and C2H2.In the reaction with C2H4, C6F5H was the major product derived from C6F6 though C2H2 was the major product of the reaction.The large amount of C2H2 seems to be derived from an additional sensitized decomposition of C2H4.C6F5H was present in minor amounts in the reaction with CH4 and HCl.Besides C6F5H, other monosubstituted products derived from C6F6 were also formed, generally within 20-100 pulses.Thus, C6F5CH3, C6F5CH=CH2, C6F5CCH, and C6F5Cl were produced, respectively, in the reaction of C6F6 with CH4, C2H4, C2H2, and HCl.In the first and last cases these products were the major ones observed.The results are discussed mechanistically in terms of the initial formation of the C6F5. radical and synthetically in terms of the utility of obtaining selective-laser-induced reduction of C6F6.
- Koga, Yoshinori,Chen, Ruth,Keehn, Philip M.
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p. 306 - 311
(2007/10/02)
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