AUTHOR=Wang Jiajia , Zhang Wei , Cao Wei , Liu Kang , Su Shihao , Ma Jing , Li Xia 

TITLE=Selective synthesis of α- and β-glycosides of N-acetyl galactosamine using rare earth metal triflates

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.1029911

DOI=10.3389/fchem.2022.1029911

ISSN=2296-2646

ABSTRACT=<p>Structures containing galactose and GalNAc residues are specifically recognized by asialoglycoprotein receptors, allowing them to selectively internalize by hepatocytes for drug-targeting delivery. However, methods for direct synthesis of GalNAc glycosides are still challenging due to the poor participating group of 2-acetamido. Here, we develop a facile strategy to synthesize various GalNAc glycosides by employing a series of rare earth metal triflates, and the results demonstrate that both <italic>α</italic>-glycosides and <italic>β</italic>-glycosides of GalNAc can be obtained by conducting with Hf(OTf)<sub>4</sub> and Sc(OTf)<sub>3</sub>, respectively. These applicable results indicate that any interested GalNAc-containing substrates could be prepared by this simple strategy.</p>