The anomeric Pudovik rearrangement

The O,O-dibenzyl-S-glycosyl phosphothioite derived from 3,4,6-tri-O-acetyl-2-acetamido-2-deoxy-l-thio-a-D-glueopyranose rearranges under the influence of triethylborane and air to provide the corresponding 1-C-pyranosyl-O,O-dibenzylphosphonothioate, a new type of carbohydrate derivative. The isomeric beta phosphothioite is compared, and evidence of a radical chain mechanism for the Pudovik rearrangement is presented. (c) 2007 Elsevier Ltd. All rights reserved.