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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 337 (1995), S. 113-124 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hydrogen abstraction of radical intermediates yielded by radical addition to the methylene compound 6, shows excellent facial selectivity. Conformational analyses of the radical intermediates were carried out by quantum chemical calculations and explain these results. The chiral radicals 7 and 8, yielded from the chiral bromides 3 and 4, lead with ethyl acrylate to the adducts 28 and 29 with more 96% de. The adduct 28 was converted to the optically active γ-valerolactone 30. The structures of the bromides 3, 4 and 31 as well as the radical adducts 19a, 24 and 25 have been verified by X-ray diffraction analysis.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0947-6539
    Keywords: heterocycles ; insertion reactions ; phosphaalkynes ; phosphorus ylides ; triphosphetenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hitherto unknown 1,2,3-triphosphetenes RC=P—PCF3—PCF3 (3a-d) are formed as main products in reactions of phosphaalkynes R—C≡P [R = iPr2N (1a), tBu (1b), Me2EtC (1c), 1-methylcyclohexyl (1d)] with the cyclotetraphosphane (PCF3)4 (2). According to NMR results the CF3 groups in 3a-d have a trans disposition; an X-ray diffraction study of 3a confirms this structure. The P—P bond lengths in 3a are equal [2.201 (2) and 2.204 (2) Å] and correspond to single bonds. A considerable shortening is observed for the sp2-C-N bond (1.336 Å) which, together with the elongation of the P=C bond (1.746 Å), indicates effective π donation of the lone pair on nitrogen. Surprisingly, 3a can be prepared in quantitative yields by reaction of the PP ylide Me3P=PCF3 (6) with 1 a (molar ratio: 2:1). In contrast, the corresponding reactions of 6 with the alkyl-substituted phosphaalkynes 1b-d lead to the novel phosphorus ylides Me3P=C(R)—P—PCF3—PCF3PCF3 [R = tBu (10a), Me2EtC (10b), 1-methylcyclohexyl (10c)] in good yields. In their molecular groundstate structures, determined by X-ray diffraction, the lone pair on the phosphano P atom prefers the syn position with respect to the ylidic P=C bond. An unusual lengthening of the sp2-C-C bond [1.553 (4) (10a), 1.543 (6) (10b), 1.551 (4) Å (10c)] to values typical for sp3-C/sp3-C distances is observed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0044-2313
    Keywords: P—Donor/Sn—Acceptor Ligands ; Pentacarbonyl Chromium Complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alternative Ligands. XXXIV. Synthesis and Ligating Properties of P-Donor/Sn-Acceptor LigandsDonor/acceptor ligands of the type Me2PCH(R)OSnMe3 [R = H(5), Me (6), Ph (7)] have been prepared by reaction of Me3SnCl with HOCH(R)PMe2 and insertion of RCHO into the SnP bond of the stannylphosphane Me3SnPMe2, respectively. The new ligands, including the ethylen-bridged analogue Me2PCH2CH2SnMe3 (1), were used for the synthesis of the pentacarbonyl chromium complexes Cr(CO)5Me2PCH2CH2SnMe3 (11) and Cr(CO)5Me2PCH(R)OSnMe3 [R = H (12), Me (13), Ph (14)]. In addition, different routes were investigated to prepare the ligand 5-7 in the coordination sphere of the Cr(CO)5-fragment. For this purpose the ligands Me2PCH(R)OH [R = H (5′), Me (6′), Ph (7′)] and the complexes Cr(CO)5Me2PCH(R)OH [R = H (15), Me (16), Ph (17)], Cr(CO)5Me2PSnMe3 (18) and Cr(CO)5PMe2H (19) were prepared. Suitable pathways were found in the two-step process of 15-17 with nBuLi to give Cr(CO)5Me2PCH(R)OLi, followed by reaction with Me3SnCl, and the condensation of 15-17 with Me3SnCl using NEt3 as base. Besides ligands 5-7 were transformed to the corresponding phosphane sulfides Me2P(S)CH(R)OSnMe3 [R = H (8), Me (9), Ph (10)] by reaction with sulfur. Analytical (C, H) and spectroscopic investigations (NMR, IR, MS,Mößbauer), in addition to an X—ray diffraction study of 7, were performed to characterize the new compounds and to deduce information on structure and bonding.
    Notes: Donor/Akzeptor-Liganden des Typs Me2PCH(R)OSnMe3 [R = H (5), Me (6), Ph (7)] wurden durch Umsetzung von Me3SnCl mit HOCH2PMe2 bzw. durch Insertion von RCHO in die SnP-Bindung des Stannylphosphans Me3SnPMe2 dargestellt. Die neuen Liganden wurden unter Einbeziehung des ethylenverbrückten Vertreters Me3SnCH2CH2PMe2 (1) zur Synthese der Chrompentacarbonylkomplexe Cr(CO)5Me2PCH2CH2SnMe3 (11) und Cr(CO)5Me2PCH(R)OSnMe3 [R = H (12), Me (13), Ph (14)] genutzt. Zusätzlich wurden unterschiedliche Wege zur Darstellung der Liganden 5-7 in der Koordinationssphäre des Cr(CO)5-Fragments untersucht und dafür die Liganden Me2PCH(R)OH [R = H (5′), Me (6′), Ph (7′)] und die Komplexe Cr(CO)5Me2PCH(R)OH [R = H (15), Me (16), Ph (17)], Cr(CO)5Me2PSnMe3 (18) und Cr(CO)5PMe2H (19) dargestellt. Als geeignet erwiesen sich die zweistufige Umsetzung von 15-17 mit nBuLi zu Cr(CO)5Me2PCH(R)OLi, gefolgt von der Reaktion mit Me3SnCl, und die Kondensation von 15-17 mit Me3SnCl unter Verwendung von NEt3 als Hilfsbase. Die Liganden 5-7 werden schließlich noch mit Schwefel zu den Phosphansulfiden Me2P(S)CH(R)OSnMe3 [R = H (8), Me (9), Ph (10)] umgesetzt. Zur Charakterisierung und zur Absicherung der Bindungsbeschreibung dienen analytische (C, H) und spektroskopische Untersuchungen (NMR, IR, MS, Mößbauer) sowie für 7 eine Röntgenbeugungsanalyse an Einkristallen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0009-2940
    Keywords: Phosphaalkyne ; [3 + 2] Cycloaddition ; 1-Aza-3,4-diphospholenes ; Diphosphiranes ; 1-Aza-3,4-diphospholes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the (diisopropylamino)phosphaethyne (1) with diazo compounds of the type R1R2C=N2 (2a-2c) unexpectedly leads in high yields (60-90%) to the 1-aza-3,4-diphospholene derivatives 3a-3c, a new class of heterocycles. NMR investigations of the analogous reaction of 1 with diazocyclopentadiene 2d show that the multi-step formation of 3a-3c proceeds via the 1-aza-3,4-diphospholes 6a-6d as intermediates.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1243-1246 
    ISSN: 0044-2313
    Keywords: Octa(silasesquioxanes) ; hydrolytic polycondensation ; γ-bromopropylocta(silasesquioxane) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structures of γ-Halopropyl-octa(silasesquioxanes)As a more rapid and versatile synthetic approach, we have studied the FeCl3-catalyzed hydrolytic polycondensation of suited trichlorosilanes in a biphasic system which yields e.g. the new octa(silasesquioxane) (BrCH2CH2CH2)8Si8O12.
    Notes: Ein Verfahren zur FeCl3-katalysierten Hydrolyse von Trichlorsilanen im Zweiphasensystem wird untersucht und das dargestellte, neue Silasesquioxan (BrCH2CH2CH2)8Si8O12 isoliert und charakterisiert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0044-2313
    Keywords: Phosphaalkyne, amino- ; nickel, platinum, cobalt complexes ; 1 λ3, 3 λ5-diphosphetene ; 1H, 13C{1H} and 31P{1H} NMR spectra ; X-ray structure determination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactive E = C(pp)π-Systems. XLII [1]. Novel Coordination Compounds of 2-(Diisopropylamino)-1-phosphaethyne: [{η4-(iPr2NCP)2}Ni{η2-(iPr2NCP)}], [(Ph3P)2Pt{η2-(iPr2NCP)}], and [Co2(CO)6{η2-μ2-(iPr2NCP)}]2-(Diisopropylamino)-phosphaethyne iPr2N—C≡P (2) reacts with the Ni(0)-complexes [Ni(1,5-cyclooctadiene)2] and [Ni(CO)3(1-azabicyclo[2.2.2]octane)], respectively, to give the novel complex [{η4-(iPr2NCP)2}Ni{η2-(iPr2NCP)}] (5), with the 1,3-diphosphacyclobutadiene derivative and 2 (side-on) as π-ligands. The molecular structure of 5 determined by X-ray diffraction on single crystals proves the spin systems and rotational barriers deduced from NMR-data (1H, 13C-, 31P). The PC distances of the four-membered ring of 1.817(2) and 1.818(2) Å - as expected - are considerably longer than the PC bond of the η2-coordinated phosphaalkyne 2 [1.671(2) Å]. - In the reactions of 2 with [(Ph3P)2Pt(C2H4)] or [Co2(CO)8] the ligand properties of 2 resemble those of alkynes affording the complexes [(Ph3P)2Pt{η2-(iPr2NCP)}] (7) with side-on coordinated 2 and [Co2(CO)6{η2-μ2-(iPr2NCP)}] with 2 acting as a 4e donor bridge in quantitative yield.In attempts to prepare copper(I) complexes of the aminophosphaalkyne 2 by reaction with CuCl or CuI the only isolable product formed in reasonable amounts under the influence of air and moisture is the 1 λ3, 3 λ5-diphosphetene (iPr2N) (10) (isolated yield: ca. 20%). The crystal structure analysis of 10 indicates a strong structural relationship to the diamino-2-phosphaallyl cation [Me(iPr2N)]+ (12), the 1,3-diphosphacyclobutadiene ligand (iPr2NCP)2 in the binuclear complex [{η1, μ2-(iPr2NCP)2}Ni2(CO)6] (3a) as well as to the heterocycles (dme)2LiOE2′ (E′ = S, 11a; E′ = Se, 11b) prepared by Becker et al. [11b, 35].
    Notes: 2-(Diisopropylamino)-phosphaethin iPr2N-C≡P (2) reagiert mit den Ni(0)-Komplexen [Ni(1,5-Cyclooctadien)2] bzw. [Ni(CO)3(1-Azabicyclo[2.2.2]octan)] zu dem neuen Komplex [{η4-(iPr2NCP)2}Ni{η2-(iPr2NCP)}] (5), der zwei Moleküle 2 in Form des 1,3-Diphosphacyclobutadiensystems und ein Molekül 2 „side-on“ koordiniert als π-Liganden enthält. Die Molekülstruktur von 5, ermittelt durch Röntgenbeugung an Einkristallen, bestätigt die aus den NMR-Daten (1H-, 13C-, 31P) abgeleiteten Spinsysteme und Rotationsbarrieren. Die PC-Abstände des Vierrings sind mit 1,817(2) bzw. 1,818(2) Å erwartungsgemäß erheblich länger als die PC-Bindung des η2-koordinierten Phosphaalkins 2 [1,671(2) Å]. Bei den Umsetzungen von 2 mit [(Ph3P)2Pt(C2H4)] bzw. [Co2(CO)8] entspricht das koordinative Verhalten dem von Alkinen; sie liefern die Komplexe [(Ph3P)2Pt{η2-(iPr2NCP)}] (7) mit side-on gebundenem 2 bzw. [Co2(CO)6{η2-η2-(iPr2NCP)}] mit 2 als 4e-Donorbrücke in quantitativer Ausbeute.Bei dem Versuch, aus 2 und CuCl bzw. CuI Kupfer(I)-Komplexe des Aminophosphaalkins darzustellen, bildet sich unter Einwirkung von Luft und Feuchtigkeit als einziges isolierbares Produkt das 1λ3, 3λ5-Diphospheten (iPr2N) (10) in beträchtlicher Menge (Reinausbeute: ca. 20%). Für 10 ergibt sich aus der Kristallstrukturanalyse eine enge Beziehung zu dem Diamino-2-phosphaallyl-Kation [Me(iPr2N)]+ (12), dem 1,3-Diphosphacyclobutadien-Liganden (iPr2NCP)2 im Zweikernkomplex [{η1-μ2-(iPr2NCP)2}Ni2(CO)6] (3a) sowie zu den von Becker et al. [11 b, 35] dargestellten Heterocyclen (dme)2LiOE2′ (E′ = S, 11a; E′ = Se, 11b).
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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