Microwave-Assisted Regioselective Benzylation: An Access to Glycal Derivatives with a Free Hydroxyl Group at C4

D-glucal, D-galactal, and their 6-O-TBDMS derivatives were benzylated in a two-step procedure under microwave conditions. In the first step glycals were converted into dibutylstannylene acetal or tributyltin ether intermediates, which were next alkylated with benzyl bromide in the presence of Bu4NBr. In all cases the 4-OH group stayed unsubstituted. Microwave-assisted benzylation contributes to a significant reduction of the reaction time in comparison with the classical synthesis, which requires several hours of heating. Supplemental materials are available for this article. Go to the publisher's online edition of Journal of Carbohydrate Chemistry to view the free supplemental file.

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