Related Experiment Video
Updated: Aug 4, 2026

Microwave-assisted Functionalization of Poly(ethylene glycol) and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation
Published on: October 30, 2013
Removal of Acyl Protective Groups from Glycopeptides: Base Does Not Epimerize Peptide Stereocenters, and
Petter Sjölin1, Mikael Elofsson, Jan Kihlberg
1Department of Organic Chemistry 2, Center for Chemistry and Chemical Engineering, The Lund Institute of Technology, Lund University, P.O. Box 124, S-221 00 Lund, Sweden.
Abstract:
Epimerization of glycopeptide stereocenters and beta-elimination have been considered as important potential side reactions on deacylation of glycopeptides which have the carbohydrate moieties protected with O-acyl groups. Since no systematic investigation of these side reactions has been reported, a model acetylated, O-linked glycotripeptide and its three epimers at the alpha-carbon stereocenters were prepared. The model glycopeptide did not undergo any epimerization (<1%) or beta-elimination, as determined by (1)H NMR spectroscopy, under various conditions which are in common use for deacetylation of glycopeptides. Under more severe conditions, which are required for removal of O-benzoyl groups, beta-elimination occurred slowly and was accompanied by slight (<5%) epimerization. The surprisingly low tendency of glycopeptides to undergo base catalyzed epimerization and beta-elimination is most likely due to protection of the alpha-carbon stereocenters by deprotonation of the adjacent amide groups.
Related Concept Videos
E2 Reaction: Kinetics and Mechanism
E2 Reaction: Stereochemistry and Regiochemistry
When a substrate with two different β hydrogens undergoes an E2 elimination, the presence of a strong base can yield two regioisomeric alkenes. The more-substituted alkene is the major product and...
E1 Reaction: Stereochemistry and Regiochemistry
Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Inhibitors of Gram-positive Cell Wall Synthesis

