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  • 1
    Electronic Resource
    Electronic Resource
    Organo-substituierte Silole durch zweifache Organoborierung von Di-1-alkinylsilanen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1107-1114 
    Details
    ISSN: 0009-2940
    Keywords: Dialkynylsilanes, intermolecular 1,1-ethyloboration of ; 1,1-Vinyloboration, intramolecular ; 3-Borylsiloles, protodeborylation of ; (Ligand)transition metal, η4 complexes of ; Sandwich complex, cyclodiastereomers of ; Siloles, boryl-organo-substituted ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organo-Substituted Siloles by Twofold Organoboration of Di-1-alkynylsilanesMe2Si(C≡CR)2 [R=Me (A), Bu (B), tBu (C), iPent (D), Ph (E), Me3Si (F)], prepared from Me2SiCl2 and MC≡CR (M=Li, Na, K), react with Et3B by 1,1-ethyloboration to form the organo-substituted siloles Me2 (1a - f) in high yields with different reaction rates: F 〉 B ≍ D 〉 A 〉 C 〉 E. Me2Si(C ≡CiPent)(C ≡ CPh) (H) and Et3B give a 5 : 1 mixture of the two regioisomeric substituted siloles 2 and 2′. - 1a and e are deborylated with H2NCH2CH2OH or MeCO2H to 3a and e, respectively. 1a reacts with maleic anhydride to yield the [4 + 2] addition compound 4a. With (OC)5Fe, Cp-Co(C2H4)2, and (CDT)Ni the cycloracemic (ligand)transition metal η41-complexes [(OC)3Fe-1a (5a), (OC)3Fe-3a (6a), CpCo-3a (7a)] and the cyclodiastereomeric η4,η41-complexes Ni-(3a)2 (8a/8a′) are formed. All products were characterized by multinuclear NMR, including measurements of J(29Si13C) and J(13C13C).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260507
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  • 2
    Electronic Resource
    Electronic Resource
    Organosubstituierte 1,1′-Spirobisilole und 1,1′-Spirobigermole durch vierfache Organoborierung von Tetra-1-alkinylsilanen und -germanen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1385-1396 
    Details
    ISSN: 0009-2940
    Keywords: Silanes, tetra-1-alkynyl- ; Germanes, tetra-1-alkynyl- ; 1,1-Ethyloboration, intermolecular ; 1,1-Vinyloboration, intramolecular ; Spirosilanes ; Spirogermanes ; Protodeborylation ; Transition metals, η41-complexes of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organosubstituted 1,1′-Spirobisiloles and 1,1′-Spirobigermoles by Fourfold Organoboration of Tetra-1-alkynylsilanes and -germanes[1]Si(C≡CR)4 [R=Me (A), R=Ph (B), R=SiMe3 (C)] and Ge(C≡CR)4 [R=Me (D), R=Ph (E)] react with Et3B by twofold intermolecular ethyloboration and twofold intramolecular vinyloboration to form the organo-substituted 5-sila(germa)spiro[4.4]nonatetraenes , R=Me: 1a, R=Ph: 1b; M=Ge, R=Me: 2d, R=Ph: 2e] via the mono-and bisethyloboration compounds 3 or 4 (e.g. 3b, 4c) with different rates: Ge 〉 Si; Me 〉 Ph. For comparison, compounds Sn(C≡CR)4 [R=Me (F), R=Ph (G)] react with Et3B in the absence of a solvent to mixtures of various spirotin compounds (5f, 5g, 6f, 8f, 9g, 10g, 11g) of which only 9g (R=Ph) corresponds to the spirosilanes and -germanes. This is the result of effective competition between intramolecular and intermolecular organoboration in the case of the tetra-1-alkynyltin compounds. The protodeborylation of 1a, b and 2d, e with MeCO2H leads to 12a, b and 13d, e, respectively. 12a isomerises by UV irradiation to allyl isomers 12a′. From 12a with 2 equiv. of maleic anhydride the 1:2 addition compound 14a is obtained, the autaddition of 12a, d leads to 15a, d. Spiro compound 12a reacts with (OC)5Fe or CpCo(C2H4)2 to give the cyclodiastereomeric η41-complexes [(OC)3Fe]2-12a (16a1-a4; X-ray structure analysis of meso- 16a1), (OC)3Fe-12a (17a) and (CpCo)2-12a (18a1-a4). - All products were characterized by multinuclear NMR, including measurements of the coupling constants 1J(13C13C), 2J(29Si29Si), nJ(29Si13C) and nJ(119Sn13C).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260617
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  • 3
    Electronic Resource
    Electronic Resource
    2,5-Dihydro-1,2,5-azoniasilaboratole Derivatives - Useful Starting Materials in Heterocyclic Synthesis (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 147-153 
    Details
    ISSN: 0009-2940
    Keywords: 1,1-Organoboration ; 1-Alkynylsilanes ; 1,2,5-Azoniasilaboratoles, 2,5-dihydro-, organo-substituted ; Heterocyclic synthesis ; Multinuclear NMR ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Alkynyl(diethylamino)dimethylsilanes [CC̊: R = Me (1a), nBu (1b), SiMe3 (1c)] react with triethylborane stereoselectively by 1,1-ethyloboration to give the alkenes with the boryl and silyl group in cis-positions at the C=C bond. Owing to the strongly intramolecular coordinative N-B bond, these products are 2,5-dihydro-1,2,5-azoniasilaboratoles (2a-c). Protic reagents such as azoles (indole, pyrazole, imidazole, triazole, indazole, benzotriazole) react with 2 to give diethylamine and the respective N-azolyl derivatives 3-8 which contain tetracoordinate boron in the case of 4-8. Compound 7, derived from indazole, was characterized by an X-ray analysis. With ethanol, the corresponding 2,5-dihydro-1,2,5-oxoniasilaboratoles 9 are obtained. Treatment of 2 with water affords 1,2,5-oxasilaborolanes 11, presumably via an intermediate 10 with the structure of a 2,5-dihydro-1,2,5-oxoniasilaboratole. All products were characterized by their 1H-, 11B-, 13C-, 15N-, and 29Si-NMR data.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290207
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