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'Cycloaddition Reactions' in keywords Facet   Publication Year 1994  [X]
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1Author    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