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  • 1,5-diphosphabicyclo[3.3.1]nonanes  (1)
  • methylenebisphosphines  (1)
  • γ-anti effect  (1)
  • 1
    ISSN: 0044-2313
    Keywords: Organophosphorus compounds, bicyclic hydrophosphorylation, intramolecular ; methylenebisphosphines ; 1,3-diphosphorinances ; 1,5-diphosphabicyclo[3.3.1]nonanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,5-Diphosphabicyclo [3.3.1]nonane1,5-Diphosphabicyclo[3.3.1]nonane 8 has been obtained by free-radical cyclization of CH2=CHCH2(H)PCH2P(H)CH2CH=CH2 6 and 1-allyl-1,3-diphosphorinane 7. For the synthesis of 6 and 7 the chlorophosphine Cl2PCH2PCl2 1 is used as a starting material, which can be converted into Me2N(Cl)PCH2P(Cl)NMe2 3 by reaction with (Me2N)2PCH2P(NMe2)2 2. Treatment of 3 with two equivalents of allyl lithium and cleavage of the PN bonds in CH2=CHCH2(Me2N)PCH2P(NMe2)CH2CH=CH2 4 with diluted HCl affords CH2=CHCH2(H)(O)PCH2P(O)(H)CH2CH=CH2 5. Phenylsilane is used for the first time as a reducing agent to obtain a secundary phosphine like 6 from the secundary phosphine oxide (5). Prolonged heating increases the yield of the byproduct 7 in the mixture of 6 and 7. Reactions of the trivalent phosphorus in 8 with CS2, CH3I, POCl3, NO, sulfur, and KSeCN, respectively, delivers the corresponding derivatives 9-17. The compounds decribed are characterized by 1H, 13C, 31P, 77Se n.m.r., i.r., and m.s. data.
    Notes: 1,5-Diphosphabicyclo[3.3.1]nonan 8 wird durch radikalische Cyclisierung von CH2=CHCH2(H)PCH2P(H)CH2CH=CH2 6 und 1-Allyl-1,3-diphosphorinan 7 erhalten. Ausgangsmaterial für die Synthese von 6 und 7 ist Cl2PCH2PCl2 1, das mit (Me2N)2PCH2P(NMe2)22 quantitativ zu Me2N(Cl)PCH2P(Cl)NMe2 3 reagiert. Die Umsetzung von 3 mit zwei Äquivalenten Allyllithium zu CH2=CHCH2(Me2N)PCH2P(NMe2)CH2CH=CH2 4 und Abspaltung der Me2N-Schutzgruppen mit verdünnter Salzsäure liefert CH2=CHCH2(H)(O)PCH2P(O)(H)CH2CH=CH2 5. Dessen Reduktion zu 6 gelingt mit C6H5SiH3. Daneben entsteht 7, das durch längeres Erhitzen angereichert werden kann. Reaktionen des dreibindigen Phosphors in 8 mit CS2, CH3I, POCl3, NO, Schwefel und KSeCN führen zu den Derivaten 9-17. Die Verbindungen werden durch 1H-, 13C-, 31P- und 77Se-NMR-sowie IR- und MS-Daten charakterisiert.
    Additional Material: 2 Tab.
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  • 2
    ISSN: 0044-2313
    Keywords: γ-anti effect ; 1-phosphabicyclo 3.3.1 nonane derivatives ; pentacarbonylchromium complex ; structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: γ-Anti Effect in 1-Phosphabicyclo[3.3.1]nonane Derivatives with Substituents at Phosphorus. Synthesis and Structure of Pentacarbonyl(1-phosphabicyclo[3.3.1]nonane) ChromiumIn 1-phosphabicyclo[3.3.1]nonane derivatives of the composition C8H15P(X) the CC-conformation always dominates. Changes in the chemical shifts of the bridge-head carbon atom C(5) in the 13C-NMR spectrum are only originated by the electronic influence of the substituent X at the phosphorus centre. Based on a homogeneous interpretation of the electronic interactions and with regard to Pearsons's definition of electronegativity the electronegativities of substituents at the phosphorus atom X = Cr(CO)5, Fe(CO)4, and Ni(CO)3 are estimated. These groups are placed in antiperiplanar orientation to the carbon atom C(5).The molecular structure of (1-phosphabicyclo[3.3.1]-nonane) Cr(CO)5 3 was elucidated by X-ray diffraction analysis. The molecule features the 1-phosphabicyclononane ligand in the CC-conformation, which has a nearly undistorted Cr(CO)5 unit coordinated to the phosphorus atom (d Cr—P = 2.368(1) Å).
    Notes: Bei 1-Phosphabicyclo[3.3.1]nonan-Derivaten C8H15P(X) dominiert stets die CC-Konformation. Änderungen der chemischen Verschiebung des C(5)-Brückenkopfatoms im 13C-NMR-Spektrum werden alleine durch den elektronischen Einfluß des Substituenten X am Phosphoratom hervorgerufen. Auf der Grundlage einer einheitlichen Interpretation der elektronischen Wechselwirkungen und unter Anwendung des Elektronegativitätsbegriffs von Pearson konnte die Elektronegativität der in antiperiplanarer Position zu C(5) stehenden Phosphorsubstituenten X = Cr(CO)5, Fe(CO)4, Ni(CO)3 abgeschätzt werden.Die Molekülstruktur von (1-Phosphabicyclo[3.3.1]-nonan) Cr(CO)5 (3) wurde mittels Röntgenbeugung ermittelt. Das Molekül zeigt das Bild eines 1-Phosphabicyclo[3.3.1]nonans in der CC-Konformation, an dessen Phosphoratom eine nahezu unverzerrte Cr(CO)5 Einheit (d Cr—P = 2,368(1) Å) koordiniert ist.
    Additional Material: 4 Ill.
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