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Description
| - The five new silanes C5Me3RSiMenCl3-n (n = 3, R = i-Pr (5); n = 2, R = i-Pr (6); n = 2, R = s-Bu (7); n = 2, R = cyclohexyl (8); and n = 3, R = t-Bu (9)) were synthesized by reaction of 1-alkyl-2,3,4-trimethylcyclopentadienyl lithium salts with appropriate chlorosilane and characterized by NMR, MS, and IR spectra. At elevated temperatures (250-360 K), all the silanes undergo a nondegenerate sigmatropic silyl rearrangement, which generates non-equivalent structures a and b. The presence of minor structure c was observed in compounds 5 and 7 only. The Diels-Alder cycloaddition of 5 with strong dienophiles tetracyanoethylene (TCNE), and dimethylacetylenedicarboxylate (DMAD) provides compounds 10 and 11, which confirmed isomers a and b, respectively. The free energy of activation of b a isomerization for compounds 5-8 evaluated from variable temperature NMR spectra show only marginal influence of group R on the 1,2-silyl shift rate.
- The five new silanes C5Me3RSiMenCl3-n (n = 3, R = i-Pr (5); n = 2, R = i-Pr (6); n = 2, R = s-Bu (7); n = 2, R = cyclohexyl (8); and n = 3, R = t-Bu (9)) were synthesized by reaction of 1-alkyl-2,3,4-trimethylcyclopentadienyl lithium salts with appropriate chlorosilane and characterized by NMR, MS, and IR spectra. At elevated temperatures (250-360 K), all the silanes undergo a nondegenerate sigmatropic silyl rearrangement, which generates non-equivalent structures a and b. The presence of minor structure c was observed in compounds 5 and 7 only. The Diels-Alder cycloaddition of 5 with strong dienophiles tetracyanoethylene (TCNE), and dimethylacetylenedicarboxylate (DMAD) provides compounds 10 and 11, which confirmed isomers a and b, respectively. The free energy of activation of b a isomerization for compounds 5-8 evaluated from variable temperature NMR spectra show only marginal influence of group R on the 1,2-silyl shift rate. (en)
- Pět nových silanů obecného vzorce C5Me3RSiMenCl3-n (n=3, R=i-Pr (5); n=2, R=i-Pr (6); n=2, R=s-Bu (7); n=2, R=cyklohexyl (8); n=3, R=t-Bu (9)) bylo připraveno reakcí 1-alkyl-2,3,4-trimethylcyklopentadienyl lithné soli s příslušným chlorsilanem a charakterizováno metodami NMR, MS a IR. Ve všech připravených silanech dochází k nedegenerovanému silatropnímu přesmyku, vedoucímu k rozdílným izomerům a a b a to již při teplotách nad 250 K. Ve sloučeninách 5 a 7 byla navíc dokázána přítomnost izomeru c. Diels-Alderova reakce sloučeniny 5 se silnými dienofily tetrakyanoethylenem (TCNE) či dimethylacetylendikarboxylátem (DMAD) vedla ke sloučninám 10 a 11, což potvrdilo předpokládanou strukturu izomerů a a b. Hodnoty standardní Gibsovy energie pro izomerizaci b->a, získané z teplotně závislých NMR měření sloučenin 5-8, ukazují na poměrně malý vliv alkylové skupiny R na rychlost 1,2-silatropního přesmyku. (cs)
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Title
| - Non-degenerate 1,2-silyl shift in silyl substituted alkyltrimethylcyclopentadienes
- Nedegenerovaný 1,2-silatropní přesmyk v alkyltrimethylcyklopentadienech substituovaných silylovými skupinami (cs)
- Non-degenerate 1,2-silyl shift in silyl substituted alkyltrimethylcyclopentadienes (en)
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skos:prefLabel
| - Non-degenerate 1,2-silyl shift in silyl substituted alkyltrimethylcyclopentadienes
- Nedegenerovaný 1,2-silatropní přesmyk v alkyltrimethylcyklopentadienech substituovaných silylovými skupinami (cs)
- Non-degenerate 1,2-silyl shift in silyl substituted alkyltrimethylcyclopentadienes (en)
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skos:notation
| - RIV/61388955:_____/05:00000579!RIV06-AV0-61388955
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http://linked.open.../vavai/riv/strany
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http://linked.open...avai/riv/aktivita
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http://linked.open...avai/riv/aktivity
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http://linked.open...iv/cisloPeriodika
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http://linked.open...vai/riv/dodaniDat
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http://linked.open...aciTvurceVysledku
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http://linked.open.../riv/druhVysledku
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http://linked.open...iv/duvernostUdaju
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http://linked.open...titaPredkladatele
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http://linked.open...dnocenehoVysledku
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http://linked.open...ai/riv/idVysledku
| - RIV/61388955:_____/05:00000579
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http://linked.open...riv/jazykVysledku
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http://linked.open.../riv/klicovaSlova
| - substituted cyclopentadienes; silatropic shift; dynamic NMR spectroscopy (en)
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http://linked.open.../riv/klicoveSlovo
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http://linked.open...odStatuVydavatele
| - CH - Švýcarská konfederace
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http://linked.open...ontrolniKodProRIV
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http://linked.open...i/riv/nazevZdroje
| - Journal of Organometallic Chemistry
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http://linked.open...in/vavai/riv/obor
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http://linked.open...ichTvurcuVysledku
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http://linked.open...cetTvurcuVysledku
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http://linked.open...UplatneniVysledku
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http://linked.open...v/svazekPeriodika
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http://linked.open...iv/tvurceVysledku
| - Mach, Karel
- Pinkas, Jiří
- Čejka, Jiří
- Gyepes, R.
- Kubišta, Jiří
- Meunier, P.
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http://linked.open...n/vavai/riv/zamer
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issn
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number of pages
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