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  • Inorganic Chemistry  (2)
  • Copper reagents  (1)
  • Wiley-Blackwell  (3)
  • 1
    ISSN: 0044-2313
    Keywords: Trihalogenogermane ; Germatrane ; Transmetalation ; Crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung, Charakterisierung und Strukturen von 1-(9-Fluorenyl)germatran and 1-(Phenylacetylenyl)germatranÜber die Synthesen der Titelverbindungen, nämlich N(CH2CH2O)3GeY (2 Y=Fluorenyl; 4 Y=PhC≡C) durch Reaktion von X3GeY (1 Y=Fluorenyl, X=Br; 5 Y=PhC≡C, X=Cl) mit N(CH2CH2OSnR3)3 (3 R=Et; 6 R=Bu) wird berichtet und die Darstellung der neuen Verbindung 1 wird beschrieben. Die Strukturen der Verbindungen wurden durch Elementaranalysen sowie mittels 1H and 13C NMR-Spektroskopie bestimmt, 2 und 4 massenspektrometrisch charakterisiert. 1, 2 und 4 wurden mit Röntgenbeugungsmethoden analysiert.
    Notes: Syntheses of the title compounds, viz. N(CH2CH2O)3GeY (2 Y=Fluorenyl; 4 Y=PhC≡C) by the reaction of X3GeY (1 Y=Fluorenyl, X=Br; 5 Y=PhC≡C, X=Cl) with N(CH2CH2OSnR3)3 (3 R=Et; 6 R=Bu) are reported including the preparation of the new compound 1. Identity and structures were established by elemental analyses, 1H and 13C NMR spectroscopy. 2 and 4 were characterized by mass spectrometry. Single crystal structures of 1, 2 and 4 were determined by X-ray diffraction methods.
    Additional Material: 3 Ill.
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  • 2
    ISSN: 1434-193X
    Keywords: Amino acids ; Spiro compounds ; Michael addition ; Copper reagents ; Curtius degradation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Racemic spiropentylglycine (8) has been synthesized by sodium borohydride reduction of benzyl (E/Z)-2-chloro-2-spiropentylideneacetate (5-Bn), nucleophilic substitution of the chlorine in the product 6 with azide and hydrogenolytic deprotection of the resulting 7 (overall yield 15%). An alternative approach to 8 consisted of the coupling of the higher-order cuprate 10, generated by halogen-metal exchange from bromospiropentane (9), with the electrophilic glycine equivalent 11 followed by deprotection (overall yield 47%). Enantiomerically pure (1′-aminospiropentyl)acetic acid [(R)-16] (overall yield 16% from 5-Me) and 1-aminospiropentanecarboxylic acid [(R)-23] (29% from 5-Me) were obtained from the Michael adduct 14-Me of (4R,5S)-4,5-diphenyloxazolidin-2-one (13) and methyl (E/Z)-2-chloro-2-spiropentylideneacetate (5-Me). Racemic 1-aminospiropentanecarboxylic acid (R/S-23) was prepared by rhodium-catalyzed addition of dimethyl diazomalonate to methylenecyclopropane and subsequent Curtius degradation of the halfester 28 via the azide 29 (overall yield 14%). Upon standing in aqueous solution, 23 underwent complete rearrangement to the new 1-amino-2-methylenecyclobutanecarboxylic acid (24). The interesting derivative of azabicyclo[3.1.0]hexane-1-carboxylate 34 with an annelated spiropentane moiety and a β-amino acid fragment was incidentally obtained in a one-step intermolecular domino reaction starting with the addition of lithium benzylamide to methyl 2-chloro-2-cyclopropylideneacetate (32, 41% yield).
    Additional Material: 2 Ill.
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  • 3
    ISSN: 0009-2940
    Keywords: Germatranes ; Organotrihalogenogermanes ; Organometallic (Si, Ge, Sn) reagents ; Transmetallation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Trialkylstannyl esters of tris(2-hydroxyalkyl)amines, N(CH2CHROSnAlk3)3 (9-11 (R = H, Me; Alk = Et, Bu), react with X3GeC(R1)(R2)COOR3 (12-17) (X = Cl or Br; R1, R2=H, Me, Ph, SiMe3, COOEt; R3=Me, Et) to give esters of α-germatranylcarboxylic acids, N(CH2CHRO)3GeC(R1)(R2)-COOR3 (1-8), in high yields. The synthesis of esters 12-17 is reported. Esters of α-germatranyldiphenylacetic acid 24 and 25 can be obtained by treatment of diphenylketene with Et3SnOMe to give in situ Et3SnC(Ph2)COOMe (23), followed by reaction with GeCl4 to give in situ Cl3GeC(Ph2)COOMe (22 and further reactions with 9 or 11, respectively. Reduction of germatrane 6 with LiAlH4 in diethyl ether leads to cleavage of the germanium-carbon bond with subsequent formation of (2-hydroxyethyl)trimethylsilane. The crystal structures of 3, 6 and 7 are reported. 1-Acyloxygermatranes 26 and 27 are obtained by treatment of 1-methoxygermatrane (28) with diphenyl- and dichloroacetic acid, respectively.
    Additional Material: 4 Ill.
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