| Popis: |
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. |
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