REACTION OF SUGAR-DERIVATIVES WITH DIBROMOMETHYL METHYL-ETHER - FORMATION OF BROMODEOXY COMPOUNDS

Treatment of methyl 4-O-benzoyl-2,3-O-isopropylidene-α-l-rhamnopyranoside and methyl 5-O-benzoyl-2,3-O-isopropylidene-α-d-lyxofuranoside with dibromomethyl methyl ether gave 2-bromo-2-deoxy-3-O-formylglycosyl bromides in good yields. Methyl 4,6-di-O-benzoyl-2,3-O-isopropylidene-α-O-mannopyranoside yielded a 6-bromo-6-deoxy-2-O-formylidose derivative via acyloxonium-ion rearrangements. Methyl 5-O-benzoyl-2,3-O-isopropylidene-β-d-ribofuranoside gave mainly a 2-bromo-2-deoxy derivative, but a small proportion of a 5-bromo-5-deoxy derivative could also be isolated. The glycosyl bromides were converted into the corresponding methyl glycosides. The O-formyl groups could be removed selectively. © 1979.