Access to l- and d-Iminosugar C-Glycosides from a d-<i>gluco</i>-Derived 6-Azidolactol Exploiting a Ring Isomerization/Alkylation Strategy

A flexible synthetic access to six-membered l- and d-iminosugar C-glycosides is reported starting from the easily available 6-azido-6-deoxy-2,3,4-tri-<i>O</i>-benzyl-d-glucopyranose precursor. This methodology involves a highly diastereoselective tandem ring enlargement/alkylation and a stereocontrolled ring contraction. It allows an efficient synthesis of iminosugar C-glycosides displaying structural diversity at both C-1 and C-6

HF-Induced Intramolecular <i>C</i>‑Arylation and <i>C</i>‑Alkylation/Fluorination of 2‑Aminoglycopyranoses

Internal <i>C</i>-aryl and <i>C</i>-alkyl glycosides derived from 2-aminoglycopyranoses have been synthesized, exploiting a HF-mediated stereoselective intramolecular glycosylation. These conditions are compatible with acetate protecting groups and allow introduction of aromatics with various electronic distributions at the anomeric position. This strategy also provides straightforward entry to original fluorinated sugar–azacycle hybrids via a tandem internal <i>C</i>-glycosylation/fluorination reaction starting from 2-<i>N</i>-allyl/propargyl glycopyranoses. All cyclizations proceed in a 1,2<i>-cis</i> stereocontrolled manner

HF-Induced Intramolecular <i>C</i>‑Arylation and <i>C</i>‑Alkylation/Fluorination of 2‑Aminoglycopyranoses

Internal <i>C</i>-aryl and <i>C</i>-alkyl glycosides derived from 2-aminoglycopyranoses have been synthesized, exploiting a HF-mediated stereoselective intramolecular glycosylation. These conditions are compatible with acetate protecting groups and allow introduction of aromatics with various electronic distributions at the anomeric position. This strategy also provides straightforward entry to original fluorinated sugar–azacycle hybrids via a tandem internal <i>C</i>-glycosylation/fluorination reaction starting from 2-<i>N</i>-allyl/propargyl glycopyranoses. All cyclizations proceed in a 1,2<i>-cis</i> stereocontrolled manner

Synthesis of 1,2-<i>cis</i>-Homoiminosugars Derived from GlcNAc and GalNAc Exploiting a β‑Amino Alcohol Skeletal Rearrangement

The synthesis of 1,2-<i>cis</i>-homoiminosugars bearing an NHAc group at the C-2 position is described. The key step to prepare these α-d-GlcNAc and α-d-GalNAc mimics utilizes a β-amino alcohol skeletal rearrangement applied to an azepane precursor. This strategy also allows access to naturally occurring α-HGJ and α-HNJ. The α-d-GlcNAc-configured iminosugar was coupled to a glucoside acceptor to yield a novel pseudodisaccharide. Preliminary glycosidase inhibition evaluation indicates that the α-d-GalNAc-configured homoiminosugar is a potent and selective α-<i>N</i>-acetylgalactosaminidase inhibitor