New synthetic approach to per-O-acetyl-isocyanates, isothiocyanates and thioureas in the disaccharide and cyclodextrin series

Abstract

An efficient method for the preparation of per-O-acetyl disaccharides and cyclodextrin isocyanates or isothiocyanates by the phosphine imide strategy is reported. Successful one-pot, high yield syntheses of cellobiose, lactose and sucrose isocyanates or/and isothiocyanates pure β-anomers have been completed starting from their corresponding monoazido-per-O-acetyl derivatives. Transformation of the ^ACEtris-6-azido-per-O-methylated and the ^ACEtris-6-azido-per-O-acetylated-α-cyclodextrins or of the 6^A-azido-6^A-deoxy-per-O-acetyl-β-cyclodextrin into the corresponding isocyanates and/or isothiocyanates is also presented. Finally the conversion of the cyclodextrin isothiocyanates by nucleophilic addition of primary and secondary amines into a large panel of original thioureido-cyclodextrins derivatives is described.