A novel chemoenzymatic approach for
the synthesis of disialyl tetrasaccharide
epitopes found as the terminal oligosaccharides of GD1α, GT1aα,
and GQ1bα is described. It relies on chemical manipulation of
enzymatically generated trisaccharides as conformationally constrained
acceptors for regioselective enzymatic α2–6-sialylation.
This strategy provides a new route for easy access to disialyl tetrasaccharide
epitopes and their derivatives