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=Volume 10 - 2022

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