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  • Organic Chemistry  (27)
  • 3,7-Dioxabicyclo[3.3.0]octanes  (1)
  • Ketene acetals, 2-(trimethylsilyl)-  (1)
  • 11
    Electronic Resource
    Electronic Resource
    Reaktionen der Trialkylsilyl-trifluormethansulfonate, III. Synthese von 1,3-Bis(trimethylsiloxy)-1,3-dienen und in 4-Stellung silylierten 3-Trimethylsiloxy-2-butensäureestern (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 2352-2362 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Trialkylsilyl Trifluoromethanesulfonates, III.  -  Synthesis of 1,3-Bis(trimethylsiloxy)-1,3-dienes and 3-Trimethylsiloxy-2-butenoates Silylated in Position 4Bis(trimethylsiloxy)-1,3-dienes 5a  -  n are obtained by reaction of 1,3-dicarbonyl compounds 1 with trimethylsilyl trifuoromethanesulfonate (2) in the presence of triethylamine (3). The silyl enol ether 8 is silylated by 2/3 to yield 1,3-bis(trimethylsiloxy)-1,3-butadiene (5o). Depending on the conditions, alkyl 3-oxobutanoates 12 react with 2/3 to give the γ-silylated alkyl 3-trimethylsiloxy-2-butenoates 15 or 16.
    Notes: Durch Umsetzung der 1,3-Dicarbonylverbindungen 1 mit Trimethylsilyltriflat (2) in Gegenwart von Triethylamin (3) erhält man die Bis(trimethylsiloxy)-1,3-diene 5a - n. 1,3-Bis(trimethylsiloxy)-1,3-butadien (5o) entsteht bei der Silylierung des Silylenolethers 8 mit 2/3. 3-Oxobutansäure-alkylester 12 werden von 2/3 je nach Reaktionsbedingungen in die γ-silylierten 3-(Trimethylsiloxy)-2-butensäureester 15 oder 16 übergeführt.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519851206
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  • 12
    Electronic Resource
    Electronic Resource
    Reaktionen der Trialkylsilyl-trifluormethansulfonate, V. Synthese und Reaktionen von N,N-Bis(trialkylsiloxy)-1-alken-1-aminen (1986)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1986 (1986), S. 1456-1465 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Trialkylsilyl Trifluoromethanesulfonates, V. - Synthesis and Reactions of N,N-Bis(trialkylsiloxy)-1-alken-1-aminesNitroalkanes 1 react with trialkylsilyl triflates 2 in the presence of triethylamine to yield N,N-bis(trialkylsiloxy)-1-alken-1-amines (nitrosoalkene acetals) 4, which are rearranged to give 2-(trialkylsiloxy)oxime O-trialkylsilyl ethers 6 by heating or by Lewis acids. 2-Amino-aldoxime O-trialkylsilyl ethers 8 or 2-aminoaldoximes 9 are obtained by reaction of amines 7 with the acetals 4.
    Notes: Nitroalkane 1 reagieren mit Trialkylsilyl-triflaten 2 in Gegenwart von Triethylamin zu N,N-Bis(trialkylsiloxy)-1-alken-1-aminen (Nitrosoalken-acetale) 4, die thermisch oder durch Lewis-Säuren in 2-(Trialkylsiloxy)oxim-O-trialkylsilylether 6 umgelagert werden. Durch Umsetzung der Acetale 4 mit Aminen 7 erhält man 2-Aminoaldoxim-O-trialkylsilylether 8 bzw. 2-Aminoaldoxime 9.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198619860817
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  • 13
    Electronic Resource
    Electronic Resource
    Reaktionen der Trialkylsilyl-trifluormethansulfonate, VIII. Synthese von O-(Trimethylsilyl)keten-O,N-acetalen, 2,5-Bis(trimethylsiloxy)pyrrolen, -furanen und -thiophenen (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 839-845 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Trialkylsilyl Trifluoromethanesulfonates, VIII. - Synthesis of O-(Trimethylsilyl)ketene O,N-Acetals, 2,5-Bis(trimethylsiloxy)pyrroles, -furans, and -thiophenesKetene O,N-acetals 3, 4, 6, 8 are obtained from N,N-diarylcarboxamides and N-acetylheterocycles 5, 7 by silylation with trimethylsilyl triflate (2) in the presence of triethylamine. Analogous reactions of carboxamides 9 and N-acyllactams 11 yield the ketene O,N-acetals 10, 12. Succinimides 13, succinic anhydrides 20, and succinic thioanhydrides 22 are doubly silylated by 2 to give the 2,5-bis(trimethylsiloxy)heterocycles 14, 21, 23. 2,5-Bis(trimethylsiloxy)furan (21a) reacts with aldehyde acetals and orthoesters 24 catalyzed by 2 to yield 2,3-disubstituted succinic anhydrides 25.
    Notes: Keten-O,N-acetale 3, 4, 6, 8 erhält man aus N,N-Diarylcarbonsäureamiden 1 und N-Acetylheterocyclen 5, 7 durch Silylierung mit Trimethylsilyl-triflat (2) in Gegenwart von Triethylamin. Die analoge Umsetzung der Carbonsäureamide 9 und N-Acyllactame 11 führt zu den Keten-O,N-acetalen 10, 12. Aus der zweifachen Reaktion von Succinimiden 13, Bernsteinsäure-anhydriden 20 bzw. Bernsteinsäure-thioanhydriden 22 mit 2 erhält man die 2,5-Bis(trimethylsiloxy)heterocyclen 14, 21, 23. 2,5-Bis(trimethylsiloxy)furan (21a) setzt sich mit Aldehyd-acetalen und Orthoestern 24 in Gegenwart katalytischer Mengen 2 zu den 2,3-disubstituierten Bernsteinsäure-anhydriden 25 um.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870838
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  • 14
    Electronic Resource
    Electronic Resource
    Reaktionen der Trialkylsilyl-trifluormethansulfonate, II. Synthese von O-Alkyl-O-(trialkylsilyl)ketenacetalen und 2-(Trialkylsilyl)carbonsäureestern (1983)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 816-834 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Trialkylsilyl Trifluoromethanesulfonates, II. - Synthesis of O-Alkyl-O-(trialkylsily1)ketene Acetals and 2-(Trialkylsilyl)carboxylatesAlkyl carboxylates 2 are silylated by trialkylsilyl triflates 1 in the presence of triethylamine (3) to yield ketene acetals 4. In reactions of the esters 6 mixtures of ketene acetals 7 and at the α-carbon silylated esters 8 are obtained. Ethanoic acid esters and lactones are doubly silylated to give the products 11, 12, and 15, respectively. Under suitable conditions silylation of the esters 10 gives rise to the 2-trimethylsilylethanoic acid esters 13. The thermodynamically more stable products are obtained. Product distributions depend on the structure of the esters and the silylating agents 1.
    Notes: Durch Silylierung mit Trialkylsilyltriflaten 1 in Gegenwart von Triethylamin (3) erhält man aus Carbonsäureestern 2 die Ketenacetale 4, die Ester 6 ergeben Gemische aus Ketenacetalen 7 und am α-Kohlenstoffatom silylierten Estern 8. Ethansäureester 10 und Lactone 14 werden durch 1/3 zweifach zu den Produkten 11, 12 bzw. 15 silyliert. Unter geeigneten Bedingungen können 2-(Trimethylsilyl)ethansäureester 13 aus den Estern 10 gewonnen werden. Es resultieren die thermodynamisch stabilen Produkte. Die Abhängigkeit der Produktverteilung von der Struktur der Reaktionspartner wird diskutiert.
    Additional Material: 10 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198319830508
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  • 15
    Electronic Resource
    Electronic Resource
    Synthese und Eigenschaften sterisch gehinderter tertiärer Amine und Guanidine (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 2178-2193 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of Sterically Hindered Tertiary Amines and GuanidinesSterically hindered tertiary amines 7, 8, 14, 17 are synthesized by reaction of the iminium salts 3, 4, and 16 with Grignard compounds 5, 12 or alkyllithium compounds 11, 13. Hindered guanidines 24 are prepared from chloroformamidinium 22 or (dichloromethane)iminium salts 26 and primary amines 23. The pKa values of the amines 7, 8, 17, and guanidenes 24 are measured, and their alkylation with methyl fluorosulfonate (31) is studied.
    Notes: Durch Umsetzung der Iminiumsalze 3, 4 und 16 mit Grignard-Verbindungen 5, 12 oder Alkyllithium-Verbindungen 11, 13 erhält man die sterisch gehinderten Amine 7, 8, 14, 17. Sterisch gehinderte Pentaalkylguanidine 24 sind aus Chlorformamidinium-22 oder Dichlormethaniminiumsalzen 26 und primären Aminen 23 zugänglich. Die pKa-Werte der Amine 7, 8, 17 und Guanidine 24 werden bestimmt, und ihre Alkylierbarkeit mit Fluorsulfonsäure-methylester (31) wird untersucht.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519851108
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  • 16
    Electronic Resource
    Electronic Resource
    Reaktionen der Trialkylsilyl-trifluormethansulfonate, VII. α-Trimethylsiloxycarboxylierung mit Tris(trimethylsiloxy)ethen (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 693-699 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Trialkylsilyl Trifluoromethanesulfonates VII. - α-Trimethylsiloxycarboxylation by Tris(trimethylsiloxy)etheneIn the presence of trimethylsilyl triflate (1), acetals and orthocarboxylic acid esters 3 react with tris(trimethylsiloxy)ethene 2 to yield 3-alkoxy- and 3,3-dialkoxy-2-(trimethylsiloxy)carboxylates 4. From carbonyl compounds 6 and the ketene acetal 2 2,3-bis(trimethylsiloxy)carboxylates 7 are obtained. Silylcarboxylates 15, 16 are formed by addition of the compound 2 to α,β-unsaturated carbonyl compounds 14 under catalysis of the Lewis acid 1. Alkylation reagents 17, 18 react with the ketene acetal 2 to give 2-(trimethylsiloxy)carboxylates 19, 20.
    Notes: In Gegenwart von Trimethylsilyltriflat (1) reagieren Acetale und Orthoester 3 mit Tris(trimethylsiloxy)ethen (2) zu 3-Alkoxy- und 3,3-Dialkoxy-2-(trimethylsiloxy)alkansäureestern 4. Aus Carbonylverbindungen 6 und dem Ketenacetal 2 erhält man die 2,3-Bis(trimethylsiloxy)carbonsäureester 7. Die Addition von 2 an α,β-ungesättigte Carbonylverbindungen 14 zu den Carbonsäuresilylestern 15, 16 wird durch die Lewis-Säure 1 katalysiert. Alkylierungsreagenzien 17, 18 setzen sich mit dem Ketenacetal 2 zu den 2-(Trimethylsiloxy)carbonsäureestern 19, 20 um.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870810
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  • 17
    Electronic Resource
    Electronic Resource
    Reaktionen der Trialkylsilyl-trifluormethansulfonate, XII. Aldol-Additionsreaktionen mit 2,6-Bis(trimethylsiloxy)thiophen-Synthese bicyclischer γ-Lactone (1992)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1992 (1992), S. 615-620 
    Details
    ISSN: 0170-2041
    Keywords: Thiophenes ; 3,7-Dioxabicyclo[3.3.0]octanes ; Aldol additions ; Lactones ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of Trialkylsilyl Trifluoromethanesulfonates, XII.  -  Aldol-Type Reactions with 2,6-Bis(trimethylsiloxy)thiophene Synthesis of Bicyclic γ-LactonesIn the presence of trimethylsilyl triflate (2) aromatic aldehydes 4 react with 2,6-bis(trimethylsiloxy)thiophene (3) to yield the 3,4-disubstituted thiosuccinic anhydrides 5. By hydrolysis of the products 5 in the presence of lead acetate the diaryl-substituted cis-bislactones 8 are obtained. Dialkyl-substituted cis-bislactones 10 are formed in a aldol addition of aliphatic aldehydes 9 to 3 catalysed by zinc chloride and subsequent hydrolysis of the intermediates. The synthesis of 3,4-bis(dialkoxyalkyl)thiosuccinic anhydrides 7 is achieved by the reaction of 3 with carboxylic acid orthoesters 6 catalysed by 2.
    Additional Material: 11 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1992199201105
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  • 18
    Electronic Resource
    Electronic Resource
    Reaktionen der Trialkylsilyl-trifluormethansulfonate, XI. Synthese von Derivaten der α-Ketocarbonsäuren aus 2-O-funktionell substituierten Trimethylsilylketenacetalen (1992)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1992 (1992), S. 607-613 
    Details
    ISSN: 0170-2041
    Keywords: 1,3-Dioxolanes ; 1,3-Oxazolidines ; α-Oxocarboxylic acids ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of Trialkylsilyl Trifluoromethanesulfonates XI.  -  Synthesis of α-Oxocarboxylic Acid Derivatives from 2-O-Functionalized Trimethylsilyl Ketene AcetalsThe cyclic ketene acetals 3, 5 are prepared from the dioxolanone 2 resp. the oxazolidinediones 4 by silylation with trimethylsilyl triflate (1)/triethylamine. In an aldol addition/Peterson olefination reaction catalysed by 1 the ketene acetals 3, 5 yield the (E/Z)-benzylidene derivatives 7, 12, 13 in reaction with aromatic aldehydes 6. In a side reaction the α-(trimethylsilyl)benzylidene derivatives 8 are formed from 3 and 6. Compounds 7 can be hydrolysed to yield α-ketocarboxylic acids 14. The latter are also obtained via β-elimination of trimethylsilanol from 2,3-bis(trimethylsiloxy)carboxylic acid esters 15 with trifluoroacetic acid anhydride/DMAP/pyridine.
    Additional Material: 11 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1992199201104
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  • 19
    Electronic Resource
    Electronic Resource
    Orthoamide, XXIII1) Umsetzungen von Orthoamidderivaten mit Verbindungen der Struktur X-CH2-CH2-Y (1972)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 762 (1972), S. 62-72 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Orthoamides, XXIII1). - Reaction of Ortho Amide Derivatives with Compounds of the Type X-CH2-CH2-Y.Reaction of the bisdialkylaminoalkoxymethanes (aminal esters) 1a, b, d and trimorpholinomethane (amide aminal, 5) with compounds of the type X-CH2-CH2-Y (X and Y = electron attracting groups) gives the mono- and bis-dialkyiaminomethylene compounds 3 or 4 by abstraction of alcohol or dialkylaminomethane.
    Notes: Die Bis-dialkylamino-alkoxy-methane (Aminalester) 1a, b, d und Trimorpholino-methan (Amidaminal, 5) reagieren mit Verbindungen der Struktur X-CH2-CH2-Y, wobei X und Y elektronenanziehende Gruppen darstellen, unter Abspaltung von Alkohol und Dialkylamin zu den Mono- und Bis-dialkylaminomethylen-Verbindungen 3 bzw. 4.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19727620107
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  • 20
    Electronic Resource
    Electronic Resource
    Synthese und Reaktionen von 2-Chlor-1,3-thiazin-4-onen (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 1249-1266 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Reactions of 2-Chloro-1,3-thiazin-4-ones2-Chloro-1,3-thiazin-4-ones 2 and 4 are prepared by cyclization of 2-thiocyanatocarboxylic acid chlorides 1 and 3, respectively, with hydrogen chloride. The compounds 2 and 4 are cyclic, azavinylogous acid chlorides of ambivalent character and react with amines undergoing substitution of chlorine or fragmentation. The structure of the 2-amino-1,3-thiazin-4-ones 9 and 14 and the aromatic character of the 1,3-thiazin-4-ones 2 and of the 1,3-thiazinium salts 18 are investigated.
    Notes: 2-Chlor-1,3-thiazin-4-one 2 und 4 sind durch Cyclisierung von 2-Thiocyanatocarbonsäurechloriden 1 bzw. 3 mit Chlorwasserstoff zugänglich. Sie besitzen als cyclische, azavinyloge Säurechloride ambivalenten Charakter und reagieren mit Aminen unter Substitution des Chlors oder Fragmentierung. Die Struktur der 2-Amino-1,3-thiazin-4-one 9 und 14 sowie der aromatische Charakter der 1,3-Thiazin-4-one 2 und der 1,3-Thiaziniumsalze 18 werden untersucht.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719770802
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