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  • 1
    ISSN: 0170-2041
    Keywords: Bicyclo[3.3.0]octane, derivatives of ; Pentalene, derivatives of ; 9-Oxatricyclo[3.3.1.02,6]nonane, derivatives of ; Oxanortwistane, derivatives of ; Phenylmetal reagents ; Phenylcuprate reagents ; Phenyllithium-cerium(III) chloride reagent ; 1,2-Addition ; Conjugate addition ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereochemistry of the Addition of Phenylmetal Reagents to Bicyclo[3.3.0]octanediones and -octadienediones.  -  Synthesis of Phenyl-Substituted Bicyclo[3.3.0]octadienesConjugate addition of dilithium diphenylcyanocuprate is observed only on one side of the dienedione 4b, affording the enedione 5b, but on both sides in the presence of boron trifluoride yielding the diphenyldione 6b. Likewise, the latter reagent gives rise to the formation of 6a from 4a. Phenylcerium(III) dichloride is much superior to phenyllithium and phenylmagnesium bromide in the 1,2 addition reaction to encumbered, enolizeable bicyclo[3.3.0]octanediones. Thus, a mixture of the diols exo,exo-8, exo,endo-8, and endo,endo-8 is formed in almost quantitative yield from the 3,7-dione 7. Furthermore, the diphenyldione 6a is transformed into the tetraphenyldiol 14 in this way and in high yield. The 2,6-dione 11b adds phenylcerium(III) dichloride affording a mixture of the hydroxyketone endo-16, which is inert towards an excess of the reagent, and the diol exo,endo-12b. The inertness of endo-16 is attributed to the formation of the cyclic hemiacetal 20 which eventually is trapped quantitatively by O-silylation with chlorotrimethylsilane in the presence of pyridine. The hydroxyketone endo-16 is dehydrated to give the enone 17 which subsequently is treated with phenylcerium(III) dichloride to form exo- and endo-19. A solution of sulfuric acid in acetic acid dehydrates the tertiary benzyl alcohols 8 (→9 + 10), endo,endo-12a (→ 13a), exo,endo-12b (→ 13b), 14 (→ 15), endo-16 (→ 17), and 19 (→ 13b) in high yields. The same results are achieved even more conveniently with a solution of chlorotrimethylsilane in dichloromethane in the absence of a base. The oxanortwistane 18 is obtained as a byproduct in the dehydration of exo,endo-12b with both reagents. The gross structures of all compounds are based on spectroscopic evidence, in particular NMR spectra. Concentration-independent IR and low-field NMR absorptions of two equivalent hydroxy groups are indicative of intramolecular hydrogen bonds and hence the endo,endo configuration of the diols endo,endo-8, endo,endo-12a, and 14. Eventually, the configurations of 5b, 6b, endo,endo-8, endo,endo-12a, exo,endo-12b, 14, 15, endo-16, and the structure of 18 as well, are established by X-ray diffraction analyses. In the solid state, the bicyclo[3.3.0]-octanols endo,endo-12a, exo,endo-12b, 14, and endo-16 adopt conformations that allow the phenyl groups the occupation of quasi equatorial positions. The optimized procedures described open high-yield routes to phenyl-substituted bicyclo-[3.3.0]octadienes starting from readily available bicyclooctanediones.
    Additional Material: 8 Ill.
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  • 2
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 3
    ISSN: 0170-2041
    Keywords: Bicyclo[3.3.0]octanes ; Tricyclo[4.2.1.03,7]nonanes ; 10-Azatricyclo[4.2.2.03,7]decanes ; Titanium tetrachloride - methanol reagent ; Vinyl sulfides, hydrocyanation of ; α-Sulfinylnitriles ; α-Cyano sulfoxides, thermolysis of ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel Tricyclic Products from Bis(arylthio)bicyclo[3.3.0]octadienes and Trimethylsilyl Cyanide in the Presence of Titanium Tetrachloride and Methanol.A four-step sequence converting ketones into α,β-unsaturated nitriles is put to test with the ketones 7 and 13. The tetramethylcyclohexanone 7 reacts with thiophenol or 4-chlorothiophenol in the presence of titanium tetrachloride and triethylamine to afford the phenyl vinyl sulphides 8. Treatment of 8 with a reagent, obtained from titanium tetrachloride and methanol, subsequent with trimethylsilyl cyanide produces the α-phenylthionitriles 9 in moderate yields. Oxidation of 9a with 3-chloroperbenzoic acid yields the α-phenylsulphinylnitrile 12 which decomposes at temperatures as low as 100°C to furnish a quantitative yield of the unsaturated nitrile 11.  -  When the mixture of bifunctional vinyl sulphides C2-, CS-14a is allowed to react at -30°C with titanium tetrachloride/methanol and, subsequently, with trimethylsilyl cyanide, a mixture of the bicyclic α-(phenylthio)nitriles exo-15 and 16 and of the tricyclic products 17 and 18 is obtained. This mixture is separated by chromatography. At 20-25°C, the otherwise identical procedure furnishes an isomer of 17, viz. the tricyclic piperidine 21a which is derived from a novel heterocyclic system. The gross structures are based on spectroscopic evidence. The configurations of 16, 17, and 21b, and the structure of 18 as well, are established by X-ray diffraction analyses. The mechanisms of the unexpected cyclization reactions leading to the tricyclic products 17, 18, and 21 are discussed.
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  • 4
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 5
    ISSN: 0009-2940
    Keywords: Bicyclo[3.3.0]octane, derivatives of ; Pentalene, derivatives of ; Phenylethynyllithium-cerium trichloride reagent ; 1,2-Addition to carbonyl groups ; Transannular reactions ; Propargyl-allenyl cation ; Vinyl cations, by addition or [2 + 2] cycloaddition to phenylethynyl groups ; Dehydro Diels-Alder reaction, intramolecular ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses, Structures, and Reactions of Phenylethynyl-Substituted Bicyclo[3.3.0]octanes[1]The bicyclo[3.3.0]octane-3,7-dione 5 adds phenylethynyl-cerium(III) dichloride to afford an almost quantitative yield of the 3,7-diols exo,exo-, exo,endo-, and endo,endo-6 (1:2:2) which are separated by flash chromatography. While both exo,endo- and endo,endo-6 are dehydrated by sulfuric acid in acetic acid to furnish the isomeric dienes C2- and Cs-7, exo,exo-6 rearranges to a bicyclic ketone (8), two tricyclic ketones (10a, b), and a tetracyclic ketone (12) as a consequence of the proximity of the endo-phenylethynyl groups. The rearrangements of exo,exo-6 are avoided when chlorotrimethylsilane is used as the dehydrating agent. Thus, a 90% yield of C2- and Cs-7 is realized from the mixture of the 3,7-diols 6. - The 2,6-dione 13 reacts with phenylethynylcerium(III) dichloride to yield the hydroxyketone endo-14 and the 2,6-diols exo,endo- and endo,endo-16 (1:1:3) which are separated by cyclic medium-pressure liquid chromatography. Dehydration of endo-14 furnishes the enone 15 which adds phenylethynylcerium(III) dichloride to afford the endo alcohol 17. Eventually, this is dehydrated to the diene 18. Formation of 18 from exo,endo-16, and endo,endo-16 as well, is accompanied by dehydrating cyclization to the oxanortwistane 19 (20%) readily separated from 18 by chromatography. - The encumbered diphenyldione 20 is converted into the highly substituted bicyclo[3.3.0]octa-2,6-diene 24 in 68% overall yield in a four-step sequence involving additions of phenylethinyl-cerium(III) dichloride (20→21 and 22→23) followed by dehydration of the endo alcohols 21 (→22) and 23 (→24). - In contrast to 20, the dicyanodiketone 25 adds phenylethynylcerium(III) dichloride at both carbonyl groups and, surprisingly, from the endo face, thus affording the exo,exo-diol 26. At 150°C, 26 undergoes quantitatively an intramolecular dehydro Diels-Alder reaction to yield the 1-phenylnaphthalene derivative. 30. The lack of incorporation of deuterium from deuterated solvents attests to the intramolecular nature of the 1,5-hydrogen shift converting the intermediate six-membered cyclic cumulene 29 to the final product 30. - Dehydration of 26 produces the highly substituted bicyclo[3.3.0]octadiene-2,6-dicarbonitrile 27 which rearranges into an equilibrium mixture of the diastereomeric bisallenes exo,exo-, exo,endo-, and endo,endo-28 on treatment with a strong base. In the same way, the identical mixture of diastereomers is obtained from each of the bisallenes 28 which had been separated by preparative medium-pressure liquid chromatography. - The gross structures of all new compounds are based on spectroscopic evidence including IR, NMR, and mass spectra. The structures of endo,endo-6, 12, exo-14, endo,endo-16 (α- and β-form), 19, 24, 26 · 2 Me2SO, 27, exo,exo-28, and endo,endo-28 are established by X-ray diffraction analyses. The preferred conformations of exo-14, endo,endo-16 (α- and β-form), and 26 · 2 Me2SO in the crystalline state, as well as the stereochemistry of the nucleophilic attack to bicyclo[3.3.0]octanediones, and the mechanisms of the intramolecular reactions between the phenylethynyl groups are discussed.
    Additional Material: 8 Ill.
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  • 6
    ISSN: 0009-2940
    Keywords: Barbaralane, 2,6-diphenyl- ; Bicyclo[3.3.1]nona-2,6-diene, 2,6-diphenyl-, deprotonation of, by butylpotassium ; Bicyclo[3.3.1]nonadienediide, dipotassium, oxidation of, by 1,2-dibromoethane ; Reversed-phase liquid chromatography, preparative, of hydrocarbons ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The diphenylbicyclo[3.3.1]nonadiene 11 is deprotonated by butylpotassium to afford the black-red crystalline dipotassium diphenylbicyclo[3.3.1]nonadienediide 12. At low temperatures, 12 is oxidized in tetrahydrofuran solution by 1,2-dibromo-ethane yielding the diphenylbarbaralane 13 which is isolated in 57% yield on a 20-mmol scale after cyclic liquid chromatography on C18 reversed-phase silica gel with methanol. The packing procedure for suitable columns is also detailed.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0009-2940
    Keywords: Bicyclo[3.3.0]octadienes, derivatives of ; Bromination, allylic, by N-bromosuccinimide ; Zinc-copper couple ; Semibullvalenes, 1,5-dimethyl-, 2,6- and 3,7-substituted ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 2,6- (6b, c) and 3,7-substituted 1,5-dimethylbicyclo-[3.3.0]octadienes C2- and Cs-9b and c are brominated by N-bromosuccinimide in the allylic positions to afford the dibromides 7b, exo,exo-7c, 10b and c, respectively. An excess of N-bromosuccinimide converts 10b into the unsymmetrical tetrabromide 11. On chromatography over silica gel, exo,exo-7c is epimerized to endo,endo-7c, while methanolysis occurs on reversed-phase chromatography yielding the dimethoxy compound 8. Under ultrasonic irradiation, the zinc-copper couple converts the bromides 7b, exo,exo-7c, 10c, and 11 into the semibullvalenes 1b, c, 2c, and 12 which are persistent in dilute solutions when atmospheric oxygen is strictly excluded. The UV/Vis spectra of 1b, c, 2c, and 12 have been recorded during reversed-phase HPLC on a Bruker ChromScan detector. Notwithstanding the absence of a classical chromophor, 1c does absorb at no less than 450 nm.
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