Uronic Acids: Occurrence and Synthetic Approaches

Uronic acid is a class of carbohydrate molecules with a carboxylic acid functional group. Uronic acids comprising polysaccharides are rich in nature and play a vital role in the biological processes of living organisms. For instance, they are part of glycosaminoglycans (e.g. heparin, dermatan, chondroitin and hyaluronan), bacterial polysaccharides, homoglycuronans, xanthan, saponins, marine polysaccharides, etc. Hence, the synthesis of uronic acid-containing polysaccharides is of high importance owing to their structural complexity and diverse biological properties. The present review outlines the occurrence of uronic acids in biologically relevant polysaccharides and focuses on several synthetic approaches to achieve uronic acids using metal and metal-free reactions.