Contributing to the Study of Enzymatic and Chemical Glycosyl Transfer Through the Observation and Mimicry of Glycosyl Cations

This account describes our efforts dedicated to: 1) the design of glycomimetics aimed at targeting therapeutically relevant carbohydrate processing enzymes, and 2) the observation, characterization, and exploitation of glycosyl cations as a tool for studying the glycosylation reaction. These findings have brought important data regarding this key ionic species as well as innovative strategies to access iminosugars of interest. 1 Introduction 2 The Glycosyl Cation, A Central Species in Glycosciences 2.1 A Selection of the Strategies Developed so far to Gain Insights into Glycosyl Cations Structure 2.2 When Superacids Meet Carbohydrates 3 Chemical Probes to Gain Insights into the Pseudorotational Itinerary of Glycosides During Glycosidic Bond Hydrolysis 3.1 Conformationally Locked Glycosides 3.1.1 The Xylopyranose Case 3.1.2 The Mannopyranose Case 3.2 Conformationally Flexible Iminosugars 3.2.1 Nojirimycin Ring Homologues 3.2.2 Noeuromycin Ring Homologues 3.2.3 Seven-Membered Iminosugar C-Glycosides 4 N-Acetyl-d-glucosamine Mimics 5 Ring Contraction: A Useful Tool to Increase Iminosugar's Structural Diversity 6 Regioselective Deprotection of Iminosugar C-Glycosides to Introduce Diversity at C2 Position 7 Conclusion