ChemInform Abstract: Reductive Cleavage of Permethylated Polysaccharides with Borane-Methyl Sulfide Complex and Butyltin Trichloride

Several per-O-methylated monosaccharides and polysaccharides were used as models in an attempt to identify more convenient reagents for accomplishing reductive cleavage of glycosidic linkages. Included in the model studies were methyl α- and β-d-glucopyranoside, methyl α- and β-d-mannopyranoside, and methyl α- and β-d-ribofuranoside. These studies led to the identification of a new promoter, butyltin trichloride, for carrying out reductive cleavage when borane-methyl sulfide complex was used as the reducing agent. These reagents were found to accomplish the reductive cleavage of per-O-methylated amylose, cellulose, and pullulan to give only the expected derivatives of 1,5-anhydro-d-glucitol. These reagents also accomplished reductive cleavage of per-O-methylated inulin to give only the expected derivatives of 2,5-anhydro-d-mannitol and 2,5-anhydro-d-glucitol. Reductive cleavage using these reagents is easy to perform, and subsequent acetylation of the products is readily accomplished in situ.