Synthesis of cyclodextrin-based carbohydrate clusters by photoaddition reactions

The syntheses of homogeneous cyclodextrin-based carbohydrate clusters, pers ubstituted with beta -D-thioglucosyl or D-thiolactosyl residues on either ( a) the primary face, (b) the secondary face, or (c) both the primary and th e secondary faces of their cyclodextrin tori, are described. The key step i n the synthetic methodology, namely the attachment of the carbohydrate resi dues to the cyclodextrin torus, proceeds in moderate-good yields (42-70%) b y the photoaddition of thiol groups, positioned at the anomeric centers of the carbohydrate residues, to allyl ether functions on the cyclodextrins. F acile removal of protecting groups then affords the free cluster compounds. Extensive 1-D and 2-D NMR spectroscopic investigations were performed on t hese compounds to determine their structures and establish their homogeneit ies, and a brief computer molecular modeling study allowed estimates of the dimensions of the clusters to be determined.