Synthesis of C1-C6 segment of carbonolide B: Wolff rearrangement of sugar α-diazo ketones

Abstract

Silver benzoate catalysed Wolff rearrangement of a series of a-diazo ketones, derived from furanuronic acids, in methanol proceeds with good yields to produce the corresponding one carbon homologated methyl-5-deoxy-hexo-furanuronate. The utility of methyl-1,2-O-isopropylidene-3-O-methyl-5-deoxy-α-d-xylo-hexo-furanuronate was demonstrated in the synthesis of the right wing segment of carbonolide B - the aglycone of the 16 membered macrolide antibiotic carbomycin B.