Iminosugar C‑Glycoside Analogues of α‑d‑GlcNAc-1-Phosphate: Synthesis and Bacterial Transglycosylase Inhibition

We herein describe the first synthesis of iminosugar C-glycosides of α-d-GlcNAc-1-phosphate in 10 steps starting from unprotected d-GlcNAc. A diastereoselective intramolecular iodoamination–cyclization as the key step was employed to construct the central piperidine ring of the iminosugar and the C-glycosidic structure of α-d-GlcNAc. Finally, the iminosugar phosphonate and its elongated phosphate analogue were accessed. These phosphorus-containing iminosugars were coupled efficiently with lipophilic monophosphates to give lipid-linked pyrophosphate derivatives, which are lipid II mimetics endowed with potent inhibitory properties toward bacterial transglycosylases (TGase)