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  • 1990-1994  (4)
  • 1985-1989  (7)
  • Organic Chemistry  (11)
  • Trialkylsilyl trifluoromethanesulfonates  (1)
  • General Chemistry
  • Nitrile hydrogen halide adducts
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  • 1
    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, VI. - Synthesis of 2-Heterosubstituted O-Alkyl-O-(trimethylsilyl)ketene Acetals and 2-(Trimethylsilyl)carboxylatesOrganooxy- and (alkylthio)ethanoic acid esters 2 are silylated by trimethylsilyl triflate (1) in the presence of triethylamine to yield mixtures of ketene acetals 3 and 2-(trimethylsilyl)ethanoates 4. The product distributions 3/4 are governed by the ester groups and the substituents in α position. Cyclic derivatives of 2-hydroxycarboxylic acids 7,9 are silylated by 1/triethylamine to give the ketene acetals 8, 10. From N-protected glycine methyl esters 11, 12 the ketene acetals 13, 15 are obtained in the reaction with 1/triethylamine.
    Notes: Durch Silylierung von Organooxy- und (Alkylthio)essigestern 2 mit Trimethylsilyltriflat (1) in Gegenwart von Triethylamin erhält man Gemische aus Ketenacetalen 3 und 2-(Trimethylsilyl)essigestern 4. Die Produktverteilung 3/4 wird durch die Estergruppen sowie die α-Substituenten in den Estern 2 gesteuert. Cyclische Derivate der 2-Hydroxycarbonsäuren 7, 9 werden durch 1/Triethylamin in die Ketenacetale 8, 10 übergeführt. N-geschützte Glycin-methylester 11, 12 ergeben bei Umsetzung mit 1/Triethylamin die Ketenacetale 13, 15.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1990 (1990), S. 745-750 
    ISSN: 0170-2041
    Keywords: Ketene acetals, 2-(trimethylsilyl)- ; Trialkylsilyl trifluoromethanesulfonates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of Trialkylsilyl Trifluoromethanesulfonates, IX.  -  Electrophilic Silylation of Electron-Rich AlkenesKetene O,O-, O,S-, and O,N-acetals 1, 7, and 9 are converted into the C-silylated derivatives 4, 8, and 11, respectively, by reaction with trimethylsilyl triflate (2a)/tertiary amine or sodium hydride. The ambident character of the ketene O,O-acetals 1 in the silylation with 2a is studied.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
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  • 3
    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, IV.  -  1,3-Trialkylsiloxy Shift - a New Rearrangement Reaction During the Silylation of NitroalkanesNitroalkanes 1 with C — H bonds in β-position react with two-fold molar amounts of trialkylsilyl triflates 2 in the presence of triethylamine to yield 2-(trialkylsiloxy)oxime O-trialkylsilyl ethers 5 by 1,3-trialkylsiloxy shift. Oxime ethers 5 are also obtained by reaction of aci-nitroalkane trialkylsilyl esters 3 with molar quantities of silylation reagents 2. The dependence of the reaction from the nature of the nitroalkane 1 and the alkyl groups in the silylation reagent 2 is investigated.
    Notes: Nitroalkane 1 mit C—H-Funktionen in β-Position ergeben bei der Silylierung mit doppelt molaren Mengen Trialkylsilyl-triflaten 2 in Gegenwart von Triethylamin unter 1,3-Trialkylsiloxy-Verschiebung 2-(Trialkylsiloxy)oxim-O-trialkylsilylether 5. Die Oximether 5 resultieren ebenso aus der Umsetzung von aci-Nitroalkan-trialkylsilylestern 3 mit molaren Mengen Silylierungsagens 2. Die Abhängigkeit der Reaktion von der Struktur der Nitroalkane 1 und der Raumerfüllung der Alkylreste am Silylierungsagens 2 wird untersucht.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 4
    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
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1986 (1986), S. 1456-1465 
    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
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  • 6
    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
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 2178-2193 
    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.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 693-699 
    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
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  • 9
    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.
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  • 10
    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
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