Synthesis of S-linked glucosaminyl-4-thiohex-2-enopyranosides via allylic S(N)2 ' substitution of a tosylhexenose

Treatment of 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-1-thio-beta -D-glucopyr anose with 1,6-anhydro-3,4-dideoxy-2-O-p-toluenesulfonyl-beta -D-erythro-he x-3-enopyranose gave 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta -D-glucopy ranosyl-(1 --> 4)-1,6-anhydro-2,3-dideoxy-4-thio-beta -D-erythro-hex-2-enop yranose in 86% yield. Its 1,6-anhydride bond was cleaved with methanol to g ive a mixture of methyl glycosides (alpha/beta similar to 5:1), from which the alpha anomer was separated by crystallization and converted into its 6- acetate, 6-methanesulfonate, or deacetylated to obtain the corresponding fr ee methyl thiodisaccharide. The structure of the new compounds was confirme d by H-1 and C-13 NMR spectra. (C) 2001 Elsevier Science Ltd. All rights re served.