Recent Advances in the Chemical Synthesis of Marine Acidic Carbohydrates

: The ocean supplies abundant active compounds, including small organic molecules, proteins, lipids, and carbohydrates, with diverse biological functions. The high-value transformation of marine carbohydrates primarily refers to their pharmaceutical, food, and cosmetic applications. However, it is still a big challenge to obtain these marine carbohydrates in well-defined structures. Synthesis is a powerful approach to access marine oligosaccharides, polysaccharide derivatives, and glycomimetics. In this review, we focus on the chemical synthesis of marine acidic carbohydrates with acidic ester groups or uronic acid building blocks including alginate, glycosaminoglycans. Regioselective sulfation using a chemical approach is also highlighted in the synthesis of marine oligosaccharides, as well as the multivalent glycodendrimers and glycopolymers for achieving specific functions. This review summarizes recent advances in the synthesis of marine acidic carbohydrates, as well as their preliminary structure activity relationship (SAR) studies, which establishes a foundation for the development of novel marine carbohydrate-based drugs and functional reagents.