General Approach to the Synthesis of Persubstituted Hydrophilic and Amphiphilic β-Cyclodextrin Derivatives

Abstract
Heptakis(2,3,6-tri-O-allyl)-β-cyclodextrin 2 was converted to heptakis[2,3,6-tri-O-(2,3-dihydroxypropyl)]-β-cyclodextrin 3 by osmium tetroxide-catalyzed dihydroxylation. A diastereomeric mixture of 3 was treated with sodium periodate followed by sodium borohydride to give heptakis[2,3,6-tri-O-(2-hydroxyethyl)]-β-cyclodextrin 5 in 86% yield. Compound 5 could be quantitatively transformed into heptakis(2,3,6-tri-O-carboxymethyl)-β-cyclodextrin 6 by TEMPO-mediated oxidation. The same reaction sequence was also applied to heptakis(2,6-di-O-allyl-3-O-methyl)-β-cyclodextrin 8, heptakis(2,3-di-O-allyl-6-O-methyl)-β-cyclodextrin 12, and heptakis(2,3-di-O-allyl-6-O-butyl)-β-cyclodextrin 16; the analogous corresponding hydroxyethyl and carboxymethyl derivatives were isolated in high yields. All products were proved to be chemically uniform.