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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 2025-2031 
    ISSN: 0947-6539
    Keywords: arenes ; carbanions ; nucleophilic aromatic substitutions ; oxidations ; reaction mechanisms ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbanions of 2-phenylpropionitrile were found to add to nitroarenes in liquid ammonia to form σH adducts, which were oxidized with KMnO4 to yield products of oxidative nucleophilic substitution of hydrogen (ONSH) in the position para to the nitro group. Treatment of the carbanion-nitroarene system with methyl iodide at -70°C indicated that the addition proceeds almost to completion. Thus, for the first time, the persistence of σH adducts, formed between free anions and mononitroarenes, has been demonstrated. It was also shown that KMnO4 oxidizes σH adducts to nitrobenzene faster than it does carbanions. This selective ONSH in the para positions of nitroarenes is a general process. However, some substituents hinder or inhibit the oxidation step.
    Additional Material: 1 Tab.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1988 (1988), S. 627-631 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktionen organischer Anionen, 139. - Stellvertretende Nucleophile Substitution von Wasserstoff in 1,2,4-Triazin-DerivatenCarbanionen mit Austrittsgruppen am anionischen Zentrum reagieren mit 1,2,4-Triazin und seinen Derivaten nach dem Muster der Stellvertretenden Nucleophilen Substitution: Wasserstoffatome in den Positionen 5, 3 oder 6 werden durch das Carbanion ersetzt. Es wird gezeigt, daß die Reaktivität der verschiedenen Triazin-Positionen gegenüber der nucleophilen Substitution des Wasserstoffs in der oben angegebenen Reihenfolge abnimmt. Die Reaktion bietet einen guten Zugang zu Triazinen mit funktionalisierten Alkylresten.
    Notes: Carbanions containing leaving groups at the carbanion centers react with 1,2,4-triazine and its derivatives according to the vicarious nucleophilic substitution scheme replacing hydrogen atoms in 5-, 3-, or 6-positions with the carbanion moiety. It is demonstrated that the activity of various positions of the triazine ring toward nucleophilic substitution of hydrogen decreases in this order. The reaction provides an efficient way of introduction of functionalized alkyl substituents into the triazine ring.
    Additional Material: 1 Tab.
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  • 3
    ISSN: 0170-2041
    Keywords: Carbanions ; Heptafulvenes ; Tropylium tetrafluoroborate ; Vicarious nucleophilic substitution ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tropylium tetrafluoroborate reacts with tertiary carbanions bearing leaving groups at the carbanionic center yielding covalent adducts. Some of them can be transformed into heptafulvenes or tropylium derivatives.
    Additional Material: 2 Tab.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 711-715 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktionen mit organischen Anionen, 142. - Reaktion von α-Chloralkylsulfonen mit Nitronaphthalinen1- und 2-Nitronaphthaline reagieren mit Carbanionen, die sich von Chlormethyl(p-tolyl)sulfon und tert-Butyl(chlormethyl)sulfon ableiten, überwiegend oder ausschließlich unter „stellvertretender nucleophiler Substitution von Wasserstoff“ in Position 2 bzw. 1. Abweichende Substitutionsmuster oder manchmal anderes Reaktionsverhalten beobachtet man bei Umsetzungen mit tertiären Carbanionen aus α-Chlorpropyl(p-tolyl)sulfon.
    Notes: 1-and 2-nitronaphthalene derivatives react with the carbanions derived from chloromethyl p-tolyl sulfone and tert-butyl chloromethyl sulfone to give products of the vicarious nucleophilic substitution of hydrogen predominantly or exclusively in position 2 and 1, respectively. A different orientation pattern and sometimes other reaction pathways are observed in the reactions involving tertiary carbanions derived from α-chloropropyl p-tolyl sulfone.
    Additional Material: 2 Tab.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1990 (1990), S. 619-622 
    ISSN: 0170-2041
    Keywords: Electron-transfer ; Radical - Carbanion coupling ; Nitroalkylation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nitronate anions derived from primary and secondary nitroal-kanes undergo cross-coupling reactions with diethyl alkylmalonate anions in alcohol/DMF solution when treated with silver nitrate. A catalytic amount of chloride ions is necessary to promote selective reaction.
    Additional Material: 3 Tab.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 90 (1978), S. 58-58 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 412-420 
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new rationalization of some phenomena in the phase-transfer catalysed processes promoted by concentrated aqueous alkali solutions, such as alkylations and β-eliminations, is proposed. It is predicted on the basis of adsorption theory and subsequently evidenced experimentally that the size of the interfacial area, controlled by the rate of stirring, affects the position of the extraction equilibrium of various anions with quaternary ammonium cations supplied by the phase-transfer catalysts.
    Additional Material: 3 Tab.
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 341-349 
    ISSN: 0894-3230
    Keywords: vicarious nucleophilic substitution ; hydrogen ; mechanism ; orientation ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hydrogens located at activated positions in electrophilic arenes, e.g. ortho and para hydrogens in nitrobenzenes, can be replaced with a nucleophile moiety provided there is at least one nucleofuge X connected to the nucleophilic centre. As the group really leaving in this hydrogen substitution process is not the hydride anion but X, the reaction has been named vicarious nucleophilic substitution of hydrogen (VNS). The concepts on the mechanism of the reaction and their experimental background are presented. Reactivity and orientation - the fundamental questions concerning synthetical applications of VNS - are discussed in light of the supposed mechanistic picture.
    Additional Material: 8 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 2229-2235 
    ISSN: 1434-193X
    Keywords: 3-Nitro-ω-benzylideneacetophenone ; Carbanions ; Michael addition ; Intramolecular vicarious nucleophilic substitution of hydrogen ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-Nitro-ω-benzylideneacetophenone (1) reacts with carbanions containing leaving groups to give addition products to the electrophilic side chain. As a result of conjugated addition and subsequent intramolecular vicarious nucleophilic substitution of hydrogen (VNS) in the nitroaromatic ring of 1 in the position para to the nitro group, 4-cyano-7-nitro-3-phenyl-1,2,3,4-tetrahydronaphthalen-1-one and 4-cyano-7-nitro-3-phenylnaphth-1-ol are obtained. Smooth intramolecular VNS in the position para to the nitro group was observed for 4-chloro-1-(3-nitrophenyl)-3-phenyl-4-(p-tosyl)butanol.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 193-198 
    ISSN: 1434-193X
    Keywords: Nucleophilic substitutions ; Azulenes ; Hydroxylation ; Amination ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Hydroxylation of azulenes with tert-butylhydroperoxide proceeds efficiently at the 6-position when the former contain electron-withdrawing substituents in the five-membered ring. Similarly, VNS amination of azulenes proceeds with 4-amino-1,2,4-triazole; its anion, being an active nucleophile, also reacts with unsubstituted azulene. A variety of transformations of 6-hydroxyazulenes, such as substitution of the corresponding sulfonates with nitrogen, oxygen, sulfur, carbon nucleophiles and halogens, and the Claisen rearrangement of allylic ethers, is reported.
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