Site-selective editing of carbohydrate scaffolds to access rare sugars enabled by photoinduced radical processes

Abstract

Rare sugars represent an important family of carbohydrates by serving as crucial intermediates in enzymatic pathways associated with glycan function. The existing methods to produce rare sugars are largely limited due to the stereochemically complex structures bearing multiple similar polar functional groups, which require lengthy procedures involving protection and deprotection. To improve the step count and atom economy of the overall procedures, the development of efficient protocols to access diverse ranges of rare sugars and their analogues with high regioselectivity remains a highly sought-after goal. In recent years, reactive glycosyl radical intermediates generated by photoredox strategies have emerged as a powerful tool to precisely edit the scaffold of unprotected and minimally protected common sugars. Hence, we summarize recent achievements via photoinduced radical-mediated strategies that enable the precise modification of carbohydrates. Furthermore, this review presents the limitations of these methods and outlines future directions.