Synthesis of a Highly Branched Nonasaccharide Chlorella Virus -Glycan Using a "Counterclockwise" Assembly Approach.

Chloroviruses produce a capsid protein containing -linked glycans differing in structure from those found in all other organisms. These species feature a core "hyper-branched" fucose residue in which every hydroxyl group is glycosylated. We describe the synthesis of a nonasaccharide from chlorella virus 1, one of most complex chlorovirus -glycans reported, using a "counterclockwise" strategy involving the sequential addition of trisaccharide, disaccharide, and monosaccharide motifs to a trisaccharide containing the core fucose residue.