Synthesis of the Diverse Glycosides in Traditional Chinese Medicine

Traditional Chinese medicine (TCM) is a huge treasure trove for the discovery and development of modern pharmaceuticals. Indeed, numerous biologically and pharmacologically significant molecules have been identified from TCM; among them, a considerable portion belongs to glycosides. These glycosides are extremely diverse in structures, consisting of a large variety of aglycones, glycans, as well as glycosidic linkages. In addition, these glycosides occur frequently as a complicated mixture of congeners in the nature sources. This micro-heterogeneity leads to the isolation of a homogeneous glycoside in an appreciable amount a formidable task. Therefore, development of synthetic approaches toward these nature glycosides has received great attention. In this account, we summarize our twenty-year efforts spent on this topic. Fifty five representative TCM-relevant glycosides synthesized by our group are highlighted. Based on the aglycone structure, these glycosides are categorized into three groups, i.e., steroid glycosides, triterpene glycosides, and flavonoid and phenolic glycosides. Typical synthetic approaches are discussed, showing the demanding tactics for regio- and stereo-controlled installation of glycans and overall manipulation of protecting groups. These expedient and scalable synthetic approaches have provided practical alternatives to the accessibility of these TCM components and thus opportunities for their in depth biological and pharmacological studies.