GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Chemistry  (30)
  • Chirality  (2)
  • 1
    Electronic Resource
    Electronic Resource
    2-(Het)aryl-Substituted 7-Azabicyclo[2.2.1]heptane Systems (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 1997-2001 
    Details
    ISSN: 1434-193X
    Keywords: Alkaloids ; Acetylcholine receptor ; Palladium ; C-C coupling ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Epibatidine (1) is a recently discovered trace alkaloid found in the skin of a Latin-American poisonous frog. Its remarkably high analgetic activity is accompanied by high toxicity. Therefore, in order to tune its biological activity, a convergent and efficient synthetic pathway was sought to synthesize epibatidine derivatives with different (het)aryl substituents. The hydro(het)arylation of the key intermediate 7-azabicycloheptene (10) represents such an approach. The synthesis of 10 by a Diels-Alder reaction of an N-activated pyrrole (7) with ethynyl p-tolyl sulfone (6) and subsequent steps has been optimized. The crucial last step, the reductive cleavage of the vinyl sulfone 9, has been replaced by a high-yield fluoride-induced degradation of the β-silylated sulfone 12 to give 10. A number of structurally different racemic epibatidine analogs (16b-e) can be prepared by palladium-catalyzed hydro(het)arylation of 10 with iodo(het)arenes 15b-e in good yields.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Suzuki Coupling of Chiral 1,1′-Binaphthyl Systems - New Synthetic Routes to Functionalize the 2- and 2,2′-Positions (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 701-709 
    Details
    ISSN: 1434-193X
    Keywords: Palladium ; Chirality ; Boron ; C-C Coupling ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,1′-Binaphthyl derivatives 1-5, substituted in the 2- or 2,2′-positions are used in palladium-catalyzed Suzuki coupling reactions. The mono- and bis-borylated coupling components 2, 4 and 5 can easily be prepared and purified, are air-stable and are therefore interesting starting materials for Suzuki coupling reactions with several aryl halides. Thus a variety of new axially-chiral 2- and 2,2′-arylated 1,1′-binaphthyls can be synthesized. Selective monoarylation of 3, 4 and 5 can be performed. Subsequent and stepwise arylation offers general access to unsymmetrically substituted binaphthyls. Moreover, interesting atropisomeric complex molecules, such as 4,4′-bis[2-(1,1′-binaphthyl)]-1,1′-biphenyl (18a), are accessible. Compounds of type 18, which can be obtained by twofold Pd-catalyzed coupling reactions, are of high potential value as ligands or promoters in catalytic, asymmetric processes or as chiral precursor molecules for host-guest interactions.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Hexacyclo[4.4.0.02,4.03, 9.05, 7.08, 10]decan, ein überbrücktes cis-Trishomobenzol (1971)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 83 (1971), S. 404-405 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19710831110
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Außergewöhnliche Cycloaddition von Tetracyanäthylen an Dispiro[2.0.2.4]deca-7,9-dien Diese Arbeit wurde von der Deutschen Forschungsgemeinschaft und vom Fonds der Chemischen Industrie unterstützt. (1975)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 87 (1975), S. 842-843 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19750872309
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    [2 + 2] - und [2 + 4] -Cycloadditionen des BicyclopropylidensGefördert mit Forschungsmitteln des Landes Niedersachsen und durch Sachspenden der Firmen Deutsche Solvay-Werke. Rheinberg/Rhld. und Degussa. Frankfurt M. (1973)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 85 (1973), S. 151-152 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19730850314
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Zum Mechanismus der thermischen Umlagerung von Bicyclo[2.2.0]hexan: Dispiro[cyclopropan-1,2′-bicyclo[2.2.0]-hexan-3′,1′′-cyclopropan] und analog substituierte Derivate als neue Modellverbindungen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3134-3150 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Mechanism of the Thermal Rearrangement of Bicyclo[2.2.0]hexane: Dispiro[cyclopropane-1,2′-bicyclo[2.2.0]hexane-3′,1′′-cyclopropane] and Analogously Substituted Derivatives as New Model CompoundsUpon thermolysis the 2,3-diazabicyclo[2.2.2]oct-2-enes 10a-c yield only the thermodynamically more stable 1,5-hexadienes, namely 11, 13, and 15, respectively. Upon photolysis, however, remarkable proportions of the new bicyclo[2.2.0]hexane derivatives 2 (66%), 4 (29%), and 3 (58%), respectively, are formed besides the hexadienes; the by-product (2%) from 10a most probably is the hexalin 12, as it would arise from an intermediate diradical by neighboring group participation of both three-membered rings. The thermolyses of 2, 3, and 4 follow first order rate laws and yield 11, 13, and 15. According to the kinetic data, which best fit a two-step mechanism, the diradical from 2 is stabilized purely electronically by 25.8 kJ/mol with respect to the diradical from 4.
    Notes: Die 2,3-Diazabicyclo[2.2.2]oct-2-ene 10a-c ergeben bei der Thermolyse nur das jeweils thermodynamisch stabilere 1,5-Hexadien, nämlich 11, 13 bzw. 15. Bei der Photolyse entstehen daneben in beachtlichen Anteilen von 66, 29 und 58% die neuen Bicyclo[2.2.0]hexan-Derivate 2, 4 bzw. 3; dem Nebenprodukt (2%) aus 10a kommt höchstwahrscheinlich die Konstitution des Hexalins 12 zu, wie es aus einem intermediären Diradikal durch Nachbargruppenbeteiligung der beiden Dreiringe entstehen müßte. Die Thermolyse von 2, 3 und 4 folgt Zeitgesetzen 1. Ordnung und führt zu 11, 13 und 15. Nach den kinetischen Daten, die am besten mit einem zweistufigen Verlauf zu vereinbaren sind, ist das 1,4-Diradikal aus 2 gegenüber dem aus 4 rein elektronisch um 25.8 kJ/mol stabilisiert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841171013
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Blitzvakuumpyrolyse von o-Alkylaryl- und Arylalkylchlorboranen Synthese benzoanellierter Boracycloalkene (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1331-1338 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Flash Vacuum Pyrolysis Of o-Alkyaryl- and Arylalkylchloroboranes. - Synthesis of Benzoannutated Boracycloalkenes The dichloroorganylboranes chosen as pyrolytic starting materials were synthesized upon treatment of the corresponding triorganylboroxines and aryltrimethylsilanes (giving 3, 4) or the tetraorganylstannanes (giving 9-12, 17-20) with boron trichloride. At 700°C the flash vacuum pyrolysis of the dichloro(2-ethylphenyl)boranes 10 and 4 led to 1-boraindanes 21 and 22 selectively. The dichloro-2-tolylborane (9), the B-dimethylamino derivative, and mesitylboranes like 3 were completely stable upon pyrolysis. Pyrolyzing the isopropylphenylborane 12 1,5-elimination exclusively took place yielding 26, while pyrolysis of propylphenylborane 11 led to a mixture of boraindane 29 and boratetraline 30. To exclude such competitive reactions, some arylalkyldichloroboranes were pyrolyzed. At 750°C dichloro(2-methylbenzyl)borane (18) exclusively yielded oligomeric 2-chloro-2-boraindane (31). At 950°C even the pyrolysis of benzyldichloroborane (17) succeeded in a 1,4-elimination reaction yielding the eight-membered 2H-benzoborete dimer 34. The inversion barrier of 34 is ΔG228=10.3 kcal mol-1, determined by NMR spectroscopy. The pyrolysis of the next-higher homologous dichloroorganylborane 19 yielded a boraindane 21 and a noncyclic diorganylborane 38 by a dehydroboration/hydroboration pathway. Both reaction types also took place when pyrolyzing dichloro[2-(2-tolyl)ethyl]borane (20): cyclization under formation of a five-membered ring system 39, formed upon attack of an aromatic C-H bond exclusively, and formation of an open-chain chlorodiorganylborane 40.
    Notes: Die als Pyrolyse-Edukte eingesetzten Dichlororganylborane wurden durch Umsetzung der entsprechenden Triorganylboroxine und Aryltrimethylsilane (zu 3, 4) oder der Tetraorganylstannane (zu 9-12, 17-20) mit Bortrichlorid gewonnen. Die Blitzvakuumpyrolyse der Dichlor(2-ethylphenyl)borane 10 und 4 führte bei 700°C selektiv zu den 1-Boraindanen 21 und 22. Das Dichlor-2-tolylboran (9) war thermisch ebenso stabil wie das B-Dimethylamino-Derivat und Mesitylborane wie 3. Auch bei der Pyrolyse des Isopropylphenylborans 12 trat ausschließlich 1,5-Eliminierung unter Bildung von 26 ein, während die Pyrolyse des Propylphenylborans 11 zu einem Gemisch aus Boraindan 29 und Boratetralin 30 führte. Um derartige intramolekulare Konkurrenzsituationen auszuschließen, wurden Arylalkyldichlorborane pyrolysiert. Dichlor(2-methylbenzyl)boran (18) lieferte bei 750°C ausschließlich oligomeres 2-Chlor-2-boraindan (31). Bei 950°C reagierte sogar Benzyldichlorboran (17) unter 1,4-Eliminierung zu dem achtgliedrigen 2H-Benzoboret-Dimeren 34. Die Inversionsbarriere von 34 wurde NMR-spektroskopisch zu ΔG228=10.3 kcal mol-1 bestimmt. Die Pyrolyse des nächsthöheren homologen Dichlororganylborans 19 lieferte ein Boraindan (21) und ein nichtcyclisches Diorganylboran 38 über eine Dehydroborierungs-/Hydroborierungsreaktion. Beide Reaktionstypen wurden auch bei der Pyrolyse von Dichlor[2-(2-tolyl)ethyl]boran (20) beobachtet: Cyclisierung ausschließlich unter Fünfringbildung (39) durch Angriff einer aromatischen C-H-Bindung und Bildung eines offenkettigen Chlordiorganylborans (40).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200811
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Borylierung von Arylsilanen, I Ein allgemeiner, einfacher und selektiver Zugang zu Phenyldihalogenboranen (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 853-854 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Upon treatment with trihaloboranes 2b-d the phenyltrimethylsilanes 1, 6, 8, and 10 yield the corresponding phenyldihaloboranes 3, 7, 9, and 11 with high selectivity. Benzylsilanes are not attacked.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200527
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Palladium  -  Catalyzed Reactions, 1 Palladium-Catalyzed Enantioselective Hydrophenylation and Hydrohetarylation of Bicyclo[2.2.1]Hept-2-ene: Influence of the Chiral Ligand, the Leaving Group, and the Solvent (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1327-1331 
    Details
    ISSN: 0009-2940
    Keywords: Asymmetric catalysis ; Hydroarylation ; Palladium ; P-N ligands ; Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of optically active biaryl bisphosphanes 10-12, a diphenylphosphanylphenyloxazoline 8, and a (β-N-sulfonyl-aminomethyl)bisdiphenylphosphane 7 as ligands in the Pd-catalyzed Heck-type hydroarylation of norbornene (1) with phenyl 2 and various hetaryl derivaties 3-5 leads exclusively to the formation of exo-2(het)arylnorbornanes 6 with asymmetric inductions of up to 86.4% ee. In addition to an investigation into the effects of different chiral ligands, a systematic study has been made of the influence of various (het)aryl compounds, leaving groups, and solvents on the chemical and optical yields of this reductive arylation.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300924
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Borylierung von Arylsilanen, II Synthese und Reaktionen silylierter Dihalogenphenylborane (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 901-905 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Upon treatment with trihaloboranes 4a and 4b the bissilylated benzenes 1, 2, and 3 yield the silylated dihalogenphenylboranes 5a-7b under substitution of one silyl group only. The corresponding difluoroboranes 5c-7c are easily accessible by a new fluorination method under mild reaction conditions by treating the dichloroboranes with lithium fluoride in ether. Upon heating with excess 4 the exchange of the second silyl group occurs, too, yielding the position-isomeric diborylbenzenes 9, 10, and 11. The bromination of the silylated dichlorophenylboranes 5a-7a proceeds with high regioselectivity under desilyation yielding 12, 13, and 14. The dimethoxyboranes 15, 16, and 17, synthesized by methanolysis of the corresponding dichloroboranes, can be coupled with bromobenzene under palladium(O) catalysis to yield the position-isomeric silylated biphenyls 18, 19, and 20.
    Notes: Die zweifach silylierten Benzole 1, 2 und 3 reagieren mit 4a, b unter Ersatz einer Silylgruppe zu den silylierten Dihalogenphenylboranen 5a-7b. Die entsprechenden Difluorborane 5c-7c sind mit einer neuen Fluorierungsmethode leicht zugänglich durch Umsetzung der Dichlorborane mit Lithiumfluorid in Ether. Durch Erhitzen mit überschüssigem 4 gelingt der Austausch der zweiten Silylgruppe unter Bildung der stellungsisomeren Diborylbenzole 9, 10 und 11. Die silylierten Dichlorphenylborane 5a-7a werden regioselektiv unter Desilylierung zu 12, 13 und 14 bromiert. Die durch Methanolyse der Dichlorborane erhaltenen Dimethoxyborane 15-17 lassen sich Palladium(O)-katalysiert mit Brombenzol zu den drei stellungsisomeren silylierten Biphenylen 18-20 kuppeln.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200606
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...