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  • 1
    Electronic Resource
    Electronic Resource
    Regioselectivity in acid- or base-catalysed acetalation of sucrose: selection of [OH-2, OH-3] or [OH-4, OH-6] diols (2000)
    Springer
    Topics in catalysis 13 (2000), S. 335-338 
    Details
    ISSN: 1572-9028
    Keywords: sucrose ; acetals ; lanthanide ; ytterbium ; resin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Regioselective monoacetalation of sucrose can be achieved without prior protection. Under acidic catalysis, and notably with the use of lanthanide-exchanged cation resins as heterogeneous catalysts, sucrose monoacetals of α,β-unsaturated carbonyl compounds involving OH-4 and OH-6 are obtained. On the other hand, the reaction of unprotected sucrose with a α-chloromethyl ketone in the presence of base provided a β-hydroxymethyl 5-membered ring acetal involving OH-2 and OH-3 as the major product, illustrating the pre-eminent reactivity of OH-2 in sucrose and its consequences on the product distribution for reactions under kinetic control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009078115615
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Consequences of the Preeminent Reactivity of 2-OH in Sucrose: Cyclic Acetalation at 2-OH and 3-OH under Basic Conditions (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 3393-3398 
    Details
    ISSN: 1434-193X
    Keywords: Sucrose ; Acetalation ; Etherification ; Carbohydrate ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of unprotected sucrose with tert-butyl chloromethyl ketone in dimethylformamide was investigated as a model for the study of the relative reactivity of the various hydroxy groups of sucrose. Besides the monoethers arising from the substitution of the chlorine atom by 2-OH and 1′-OH of sucrose, the major product is a tert-butyl hydroxymethyl 5-membered ring acetal involving 2-OH and 3-OH. The formation of this product illustrates the preeminent reactivity of 2-OH towards the carbonyl group of the α-chloromethyl ketone, leading to an intermediate hemiacetalic anion, which can enter by intramolecular acetal formation through an intermediate epoxide.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
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