Highly convergent synthesis of a β-mannuronic acid alginate hexadecasaccharide.

Solution-phase synthesis of poly-β-mannuronic acids still remains unexplored. We report the first synthesis of a β-mannuronic acid alginate hexadecasaccharide representing the longest synthetic polymannuronic acid so far. The highly convergent synthetic approach provides a new avenue to access poly-β-mannuronic acids that can enable the biological evaluation of poly-β-mannuronic acids as potential therapeutics and vaccines.