EFFICIENT GENERATION OF BETA-L-RHAMNOSIDIC LINKAGES VIA THE ULOSYL BROMIDE APPROACH

Practical protocols have been developed for the acquisition of ulosyl bromides of type III from L-rhamnose, i.e. 6-deoxy-alpha-L-arabino-2-k etohexosyl bromides 6-8. They have high potential as indirect beta-L-r hamnosyl donors, as they undergo beta-specific glycosidations under Ko enigs-Knorr conditions, and carbonyl reductions of the resulting beta- L-ulosides proceed with high beta-L-rhamno selectivity. (C) 1997 Elsev ier Science Ltd.