Montmorillonite K-10 promoted synthesis of chiral dioxa-caged compounds derived from levoglucosenone

• A short and efficient synthesis of chiral dioxa-caged compounds from levoglucosenone is presented.
• The key transformation, involving a cascade 3-step cationic cyclization, was carried out using Montmorillonite K-10 catalysis.
• The usefulness of K-10 in related semi-pinacol rearrangements to obtain piran-3-ones is also shown.
• DFT calculations provide theoretical explanation for different reactivity patterns.

A short and efficient methodology for the synthesis of chiral dioxa-caged compounds from levoglucosenone, a biomass-derived enone, is herein presented. The key transformation, that involves a cascade 3-step cationic cyclization, was efficiently carried out in high yields and selectivities by Montmorillonite K-10 catalysis. The usefulness of K-10 in related semi-pinacol rearrangements to obtain pyran-3-ones is also shown. Interesting differences in the reactivity pattern was found for epimeric alcohols, and the origins of these findings were determined by DFT calculations.

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