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'Silaheterocycles' in keywords
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1994 (1)
1992 (3)
1Author    N. Orbert Auner, Erika PenzenstadlerRequires cookie*
 Title    Silaheterocyclen, XIII Erzeugung und Cycloadditionsverhalten von l,3-Diaza-2,4-disila-unj 1.3-Disilacyclobutanen mit exocyclischer SiC-Doppelbindung Silaheterocycles, XIII Form ation and Cycloaddition Reactions of l,3-Diaza-2,4-disila-and 1.3-Disilacyclobutanes Containing an Exocyclic SiC Double Bond  
  Reference    Z. Naturforsch. 47b, 217 (1992); eingegangen am 16. Juli/19. August 1991 
  Published    1992 
  Keywords    Silaheterocycles, Synthesis o f l, 3-Diaza-2, 4-disilacyclobutane, Form ation o f Silenes, Cycloaddition Reactions 
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 TEI-XML for    default:Reihe_B/47/ZNB-1992-47b-0217.pdf 
 Identifier    ZNB-1992-47b-0217 
 Volume    47 
2Author    N. Orbert Auner, Erika Penzenstadler, Eberhardt HerdtweckRequires cookie*
 Title    Silaheterocyclen, XX Aminosubstituierte Vinylchlorsilane und Silaethene: Bausteine zur Synthese von l,3-Diaza-2-silacyclopentanen [1] Silaheterocycles, XX Am inosubstituted Vinylchlorosilanes and Silenes: Building Blocks for the Synthesis of l,3-Diaza-2-silacyclopentanes [1]  
 Abstract    The amino-substituted vinylchlorosilanes 4 -7 are synthesized from N ,N ,N '-trim ethyl-ethylenediamine (8 a) or tris(trimethylsilyl)ethylenediamine (8 b), LiBu" and organodichloro-vinylsilanes. 5 eliminates trimethylchlorosilane when distilled and yields 1,3-diaza-2-silacyclopentane 9, whereas the com pounds 6 and 7 show a great tendency to oligomerize. The reaction o f 4 with LiBu1 gives a neopentylsilene intermediate 10 a which can be trapped by isoprene or 1,3-butadiene yielding small amounts o f the Diels-Alder products 11 and 12, re­ spectively. The main reaction pathway for 10 a is rearrangement with migration o f a M e3Si-group from nitrogen to the silene's carbon atom and a new N —Si bond formation to give the diazasilacyclopentane 10 which has been characterized by X-ray diffraction analysis. This in­ tramolecular rearrangement appears to involve a pentacoordinated silene Si-atom. N o dimer-isation o f 10a to a disilacyclobutane is observed. The introduction o f a second Si-tris(tri-methylsilyl)ethylenediamine substituent at the SiC frame work does not result in silene stabili­ sation: there is no evidence for Si-hexacoordination in silene 15 nor in the [4+2] cyclo-addition product with isoprene (14). 
  Reference    Z. Naturforsch. 47b, 1377—1385 (1992); eingegangen am 6. Mai 1992 
  Published    1992 
  Keywords    Silaheterocycles, Synthesis, Form ation o f Silenes, Cycloaddition Reactions, Highly C oordinated Silicon 
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 TEI-XML for    default:Reihe_B/47/ZNB-1992-47b-1377.pdf 
 Identifier    ZNB-1992-47b-1377 
 Volume    47 
3Author    N. Orbert Auner, Erika PenzenstadlerRequires cookie*
 Title    Silaheterocyclen, XVII Synthese und Cycloadditionsreaktionen neuartiger, aminocyclischer Silaethene [1] Silaheterocycles, XVII Synthesis and Cycloaddition Reactions of Novel Amino Cyclic Silenes [1]  
 Abstract    The silene 2 is formed by reacting 2-chloro-l,3-bis(trimethylsilyl)-2-vinyl-1,3-diaza-2-silacyclopentane (5) with LiBu' in «-pentane in the tem perature range from -1 0 to +10 °C. The reaction primarily leads to the corresponding a-lithio adduct 6 by addition of the Li-organyl to the vinyl group o f 5; subsequent 1,2-LiCl elimination yields 2 as an intermediate. 2 can be trapped by polar reagents M e3SiX (X = OMe, 0 S 0 2C F 3) as well as by organic dienes which add across the Si = C bond; in the absence of trapping agents, trisilacyclohexane 7 is isolated. The cycloaddition behaviour of 2 is best described by the two mesomeric formulae (a) and (ß), with competitive [4+2] and [2 + 2] addition routes: While with butadienes and norbor-na-2,5-diene the [2 + 2] products are formed mainly in a multiple step reaction via zwitterionic intermediates (1,4 dipoles), the ratio o f the [4+2]/[2 + 2] derivatives from 2 and cyclohexa-1,3-diene becomes nearly equivalent. 2 is thus quite com parable in its reactivity to dichloro-neopentylsilene, Cl2Si = C H C H 2Bu'. 
  Reference    Z. Naturforsch. 47b, 795—804 (1992); eingegangen am 25. November 1991 
  Published    1992 
  Keywords    Silaheterocycles, Synthesis, 1, 3-Bis(trimethylsilyl)-1, 3-diaza-2-silacyclopentane, F orm ation o f Silenes, Cycloaddition Reactions 
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 TEI-XML for    default:Reihe_B/47/ZNB-1992-47b-0795.pdf 
 Identifier    ZNB-1992-47b-0795 
 Volume    47 
4Author    Norbert Auner, Carola Wagner, Wolfgang ZieheRequires cookie*
 Title    Silaheterocyclen, XXVII. Substituenteneffekte zur Steuerung des Cycloadditionsverhaltens von Silaethenen [1] Silaheterocycles, XXVII. Controlling the Cycloaddition Behavior of Silenes by Substituent Effects [1]  
 Abstract    The silene Cl2Si=C(Ph)CH2Bu' (2) is formed by the reaction o f l,l,l-trichloro-2-phenyl-l-silaprop-2-ene (1) with LiBu' in n-pentane in the temperature range from -1 5 to 0 °C. TTie reaction initially leads to the corresponding a-lithio adduct A (addition o f LiBu' to the vinyl group of 1); subsequent LiCl elimination yields 2 as an intermediate. 2 can be trapped by Me3SiOMe (3) and dienes which add across the Si=C bond. In the absence of trapping agents but in the presence of the Lewis base N E t3 the mixture 1/LiBu' reacts to give the disilacyclobutane 4. Due to its electronic and steric properties, Cl2Si=C(Ph)C H 2Bu' (2) and butadienes yield mainly the D iels-A lder adducts (5, 7, 9) while with styrene and 1,3-cyclo-hexadiene the [2 + 2] and [4 + 2] products are formed in competition. With 2-norbornene, 2,5-norbornadiene and quadricyclan the [2 + 2] and [2 + 2 + 2] products are formed selectively but only in low yields. In all reactions except with quadricyclan an ene-reaction com petes with the cycloaddition leading to ene-com pounds as by-products. 
  Reference    Z. Naturforsch. 49b, 831 (1994); eingegangen am 18. Februar 1994 
  Published    1994 
  Keywords    Silaheterocycles, l, l, l-Trichloro-2-phenyl-l-silaprop-2-ene, Substituent Effects, Formation of Silenes, Cycloaddition Reactions 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-0831.pdf 
 Identifier    ZNB-1994-49b-0831 
 Volume    49