# Exploring the Chemistry and Applications of Thio-, Seleno-, and Tellurosugars

## TL;DR

This paper reviews the chemistry and uses of thio-, seleno-, and tellurosugars, which are modified sugars with potential applications in medicine and biology.

## Contribution

The paper provides a comprehensive review of synthetic methods and biological properties of thio-, seleno-, and tellurosugars.

## Key findings

- Substituting oxygen atoms in sugars with sulfur, selenium, or tellurium can alter their bioavailability and bioactivity.
- Various synthetic methods, including metal-catalyzed and organocatalytic reactions, are effective for producing these modified sugars.
- These glycomimetics show promising properties such as redox activity and interactions with pathological enzymes.

## Abstract

Given the crucial roles of carbohydrates in energy supply, biochemical processes, signaling events and the pathogenesis of several diseases, the development of carbohydrate analogues, called glycomimetics, is a key research area in Glycobiology, Pharmacology, and Medicinal Chemistry. Among the many structural transformations explored, the replacement of endo- and exocyclic oxygen atoms by carbon (carbasugars) or heteroatoms, such as nitrogen (aza- and iminosugars), phosphorous (phosphasugars), sulfur (thiosugars), selenium (selenosugars) or tellurium (tellurosugars) have garnered significant attention. These isosteric substitutions can modulate the carbohydrate bioavailability, stability, and bioactivity, while introducing new properties, such as redox activity, interactions with pathological lectins and enzymes, or cytotoxic effects. In this manuscript we have focused on three major families of glycomimetics: thio-, seleno-, and tellurosugars. We provide a comprehensive review of the most relevant synthetic pathways leading to substitutions primarily at the endocyclic and glycosidic positions. The scope includes metal-catalyzed reactions, organocatalysis, electro- and photochemical transformations, free-radical processes, and automated syntheses. Additionally, mechanistic insights, stereoselectivity, and biological properties are also discussed. The structural diversity and promising bioactivities of these glycomimetics underscore their significance in this research area.