Diisobutylaluminium-promoted regioselective de-O-methylation of cyclodextrins: an expeditious entry to selectively modified cyclodextrins

Substituted cyclodextrins carrying methyl groups on the primary rim undergo highly regioselective de-O-methylation in the presence of benzyl groups. u sing diisobutylaluminium. This gave access to AD or AB di-6-O-demethylated derivatives, which were fully characterised by NMR. MS and chemical degrada tion using the hex-5-enose method. Direct functionalisation of these deriva tives, for example by glycosylation, makes this method an attractive proced ure for the preparation of modified cyclodextrins. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.