SYNTHESIS OF ALKYL 2-DEOXY-α- D -GLYCOPYRANOSIDES AND THEIR 2-DEUTERIO DERIVATIVES

The methyl, cyclohexyl, and t-butyl 2-deoxy-2-iodo-α-D-manno-and β-D-glucopyranoside triacetates were formed in near quantitative yield on reaction of equimolar amounts of the corresponding alcohol, iodine, D-glucal triacetate, silver perchlorate, and 2,4,6-trimethylpyridine (collidine) in dry benzene. The proportion of the α-D-manno isomer in the product increased in the order, t-butyl > cyclohexyl > methyl. Deuterolysis of the iodide in the presence of palladium proceeded with retention of configuration when the iodine was in equatorial orientation (β-D-gluco-configuration) but with near complete lack of stereospecificity when axially oriented (α-D-manmo-configuration).