- Mechanosynthesis of Odd-Numbered Tetraaryl[n]cumulenes
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A mechanochemical synthesis of one-dimensional carbon allotrope carbyne model compounds, namely tetraaryl[n]cumulenes (n=3, 5) was realized. Central for the mechanosynthesis of the cumulenic carbon nanostructures were the development of a mechanochemical Favorskii alkynylation-type reaction and the implementation of a solvent-free, acid-free reductive elimination with tin(II) chloride by ball milling.
- Ardila-Fierro, Karen J.,Bolm, Carsten,Hernández, José G.
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supporting information
p. 12945 - 12949
(2019/08/01)
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- Alkyl group-tagged ruthenium indenylidene complexes: Synthesis, characterization and metathesis activity
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We report on the synthesis of ruthenium indenylidene catalysts [RuCl2(3-R-1-indenylidene)(PCy3)2 in which R is iso-propyl (7a), tert-butyl (7b) or cyclohexyl (7c)]. The obtained alkyl tagged indenylidene catalysts were ana
- Yu, Baoyi,Hamad, Fatma B.,Leus, Karen,Lyapkov, Alex A.,Van Hecke, Kristof,Verpoort, Francis
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p. 148 - 154
(2015/06/22)
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- CATALYST COMPLEXES WITH CARBENE LIGAND AND METHOD FOR MAKING SAME AND USE IN METATHESIS REACTION
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This invention relates to catalyst compounds and the synthesis and applications useful in olefin metathesis reactions. The catalyst compounds of the invention are represented by the formula (I): wherein M is a Group 8 metal; X1 and X2/sup
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Page/Page column 27
(2014/07/23)
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- Bronsted acid-catalyzed cycloisomerization of but-2-yne-1,4-diols with or without 1,3-dicarbonyl compounds to tri- and tetrasubstituted furans
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A Bronsted acid-catalyzed method to prepare tri- and tetrasubstituted furans efficiently from cycloisomerization of but-2-yne-1,4-diols with or without 1,3-dicarbonyl compounds is described. By taking advantage of the orthogonal modes of reactivity of the alcoholic substrate through slight modification of the reaction conditions, a divergence in product selectivity was observed. At room temperature, p-TsOH?H 2O-mediated tandem alkylation/cycloisomerization of the propargylic 1,4-diol with the β-dicarbonyl compound was found to selectively occur to provide the tetrasubstituted furan product. On the other hand, increasing the reaction temperature to 80 °C was discovered to result in preferential p-TsOH?H2O-catalyzed dehydrative rearrangement of the unsaturated alcohol and formation of the 2,3,5-trisubstituted furan adduct.
- Mothe, Srinivasa Reddy,Lauw, Sherman Jun Liang,Kothandaraman, Prasath,Chan, Philip Wai Hong
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experimental part
p. 6937 - 6947
(2012/10/07)
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- 1-Halo-1-acceptor-/1,1-diacceptor-substituted allenes, 9: Functionalized allenes, haloallenes, and bisallenes via [2,3]/[3,3]-sigmatropic rearrangements and their reactivity
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Reaction of carbonyl compounds 1 with trimethylsilylacetylene 2 leads to the alkynols 3, which are excellent precursors of acceptor-substituted allenes. Compound 3 reacts with carbamoyl chloride 4, diethyl chlorophosphate 6, or hypohalite 8 to give the substituted alkynols 5, 7, 9. Reaction of 9 with sulfinyl chloride 10 leads to the sulfinic esters 11, which on heating undergo a [2,3]-sigmatropic shift to yield the halosulfonyl allenes 12. In the same manner the reaction of 7 and 9 with chlorophosphanes 13 or sulfenyl chlorides 15 gives rise to the generation of the phosphoryl allenes 14 and the haloallenyl sulfoxides 16, respectively. Alkynyl ketene acetal intermediates 18 are formed by starting from the alkynols 9 and orthoesters 17. Spontaneous [3,3]-sigmatropic rearrangement of 18 gives the haloallenyl esters 19. Reaction of alkynols 5 with sulfur dichloride leads to the alkynylsulfinyl esters 20, which on heating rearrange to the bisallenyl sulfones 21. Pyrolysis of 21 yields the thiophene 1,1-dioxides 22. Bisphosphorylbisallene 24 is synthesized from hexadiyndiol 23 by reaction with chlorodiethoxyphosphite. Halophosphoryl allenes 14 react with bromine to yield the oxaphospholenes 25 by cyclization and subsequent elimination of ethanol, or oxaphospholenes 26, if no appropriate leaving group is present in the molecule. Sulfonyl-1,3-dienes 27 can be synthesized by reaction of halosulfonylallenes 12 with bromine, followed by elimination of HBr. Haloallenyl ester 19a is converted in a non-generalizable reaction with bromine into the tribromo3,6-dihydro-2-pyranone 30. VCH Verlagsgesellschaft mbH, 1996.
- Saalfrank, Rolf W.,Welch, Andreas,Haubner, Martin,Bauer, Udo
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p. 171 - 181
(2007/10/03)
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- Optically active propargyl alcohol derivative and a method for preparation of the same
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An optically active propargyl alcohol derivative of the formula (I) STR1 wherein X=phenyl or thienyl and R=lower alkyl, halogenated methyl, phenyl or substituted phenyl having at least one lower alkyl radical and or halogen atom, is prepared by contacting a racemic modification of l- and d-isomers of the formula (I) with l-brucine in an organic solvent, by separating the resultant deposited diastereomer from a solution containing the resultant other diastereomer in the organic solvent, by decomposing each diastereomer with an aqueous mineral acid solution in the presence of an organic solvent capable of dissolving the corresponding optically active isomer dissociated from the diastereomer and incompatible with water so as to allow the optically active isomer to be dissolved in the water-incompatible organic solvent, and by recovering the optically active isomer from the solution thereof.
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