Regioselective opening of proximally sulfato-capped cyclodextrins.

Sulfato groups capping one or two pairs of adjacent glucose units in methylated cyclodextrin (CD) derivatives have been found to undergo regioselective opening with various nucleophiles; the reported methodology opens the way to the efficient synthesis of tridifferentiated α- and β-cyclodextrins that constitute key starting materials for the preparation of heteropolydentate cavitands.