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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 908-913 
    ISSN: 0044-2313
    Keywords: Methylene-bridged Phosphines ; Phosphaalkenes ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Molecular Structure of new Ring Systems from 1,1,3,3-Tetrachloro-1,3-diphosphapropane1,1,3,3-Tetrachloro-1,3-diphosphapropane 1 reacts in two different ways to form new heterocycles. Partial oxidation of 1 with tetrachloroorthobenzoquinone furnishes the methylene-bridged λ3P, λ5P species 3. Subsequent reactions with di- and triethylamine lead to the condensed ring system 6 with the P=C bonds connected to a central four-membered ring. Compound 6 displays crystallographic inversion symmetry, a short transannular P—P distance and an extremely distorted tetrahedral coordination geometry at the four-membered ring phosphorus atoms. 1 reacts with 7 to give the heterocycle 8 with a central eight-membered ring involving four phosphorus atoms. The eight - membered ring shows a „bent“ crown conformation, the condensed five - membered rings display envelope conformation.
    Notes: Aus 1,1,3,3-Tetrachlor-1,3-diphosphapropan 1 lassen sich auf zwei verschiedenen Reaktionswegen neue Heterocyclen gewinnen. Die Oxidation von 1 mit einem Äquivalent Tetrachlororthobenzochinon führt zu der methylenverbrückten λ3P, λ5P Spezies 3. Bei der anschließenden Umsetzung mit Di- und Triethylamin entsteht das kondensierte Ring-system 6 mit am zentralen Vierring exocyclisch angeordneten P=C Bindungen. 6 zeigt kristallographische Inversionssymmetrie, einen kurzen P—P Transannularabstand und eine extrem verzerrte tetraedrische Koordinationsgeometrie an den λ5-Phosphoratomen. 1 und 7 reagieren unter Bildung eines Heterocyclus mit einem zentralen Achtring mit vier alternierend angeordneten Phosphoratomen. Der Achtring liegt in einer „geknickten“ Kronenform vor, die ankondensierten Fünfringe besitzen Briefumschlagkonformation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0009-2940
    Keywords: Phosphaalkenes ; Cycloadditions ; Insertion reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dimethylamino-substituted phosphaalkene 1 reacts with hexafluoroacetone (HFA) with addition at the P=C bond to form the 1,5,2-dioxaphosphorinane 2. The structure of 2 was confirmed by an X-ray crystal structure analysis. The six-membered ring displays an envelope conformation with the phosphorus atom out of the plane, but the phosphorus is disordered over two sites. Reaction of P-trimethylsilyl-substituted phosphaalkenes with HFA proceeds with retention of the P=C double bond and insertion of HFA into the P—Si bond. Two isomeric products are obtained and are characterized by 1H-, 13C-, 19F-, and 31P-NMR spectroscopy, IR spectroscopy, mass spectrometry, and elemental analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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