Selective modification of mono-altro-β-cyclodextrin: dependence of O-sulfonylation position on the shape of sulfonylating reactant

Mono-altro-β-cyclodextrin, which has 21 different hydroxyl groups, was selectively sulfonylated by 2-naphthalenesulfonyl chloride at the 2^A-OH of the altrose residue. By using 1-naphthalenesulfonyl chloride as reactant, the 3^G-OH of the neighboring glucose became available for selective sulfonylation, and the resulted sulfonate was proved to be a very important intermediate for introducing functionalities to the saccharide adjacent to the altroside of mono-altro-β-cyclodextrin that is capable of controlling the orientation of substrate.