Chemical Synthesis of Cyclodextrins by Using Intramolecular Glycosylation

An efficient synthesis of cyclodextrins (CDs) by using the intramolecular glycosylation is
demonstrated. α-CD, an α(1→4)linked hexaglucoside, was prepared via a block condensation of
three maltose units. A modified key maltose intermediate as a precursor to both glycosyl donor
and acceptor components was prepared in 6 steps starting from maltose. All the glycosylation for
chain elongation and cyclization of saccharides was carried out after tethering the donor to the
acceptor by the phthaloyl bridge to give the desired saccharides in good yields with complete
α-selectivity. δ-CD composed of 9 glucose units was synthesized by the same manner from three
maltotriose units.