Hydrogen-Bond-Mediated Glycosylation Reactions with Glycosyl Picolinates
Mohan Lal1,2, Himanshu Gangwar1,2, Anand Gaurav1,2
1Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow 226031, India.
Abstract:
Herein, we report a generally applicable hydrogen-bond-mediated glycosylation protocol of glycosyl picolinate donors with a charged (thio)urea hydrogen-bond-donor catalyst. A variety of nucleophiles, including complex natural products, glycosides, amino acids, and less nucleophilic phenolic acceptors were also glycosylated successfully. Hydrogen-bond-mediated glycosylation systems combined with different strategies were also explored to achieve stereoselective glycosylation. A mechanistic study revealed that catalysts form the donor-catalyst noncovalent complex through hydrogen bonds and then produce the oxocarbenium species.
Related Concept Videos
Oligosaccharide Assembly
Multiple sugar molecules that may or may...
Protein Glycosylation
Glycosylation occurs in...
Preparation of Diols and Pinacol Rearrangement
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
Proteoglycans
Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview
Aldehydes and Ketones with Water: Hydrate Formation
The formation of hydrates is a reversible reaction. Hydrate formation is influenced by steric and electronic factors accompanying the alkyl substituents on the carbonyl group: The rate of hydrate formation increases with a decrease in the number of alkyl groups attached to the carbonyl carbon. Hence,...


