Recent Developments in the Ferrier Rearrangement

The development of glycobiology relies on the sources of particular oligosaccharides in their purest forms. As the isolation of the oligosaccharide structures from natural sources is not a reliable option for providing samples with homogeneity, chemical means become pertinent. The growing demand for diverse oligosaccharide structures has prompted the advancement of chemical strategies to stitch sugar molecules with precise stereo- and regioselectivity through the formation of glycosidic bonds. This Review will focus on the key developments towards chemical O-glycosylations in the current century. Synthesis of novel glycosyl donors and acceptors and their unique activation for successful glycosylation are discussed. This Review concludes with a summary of recent developments and comments on future prospects.

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Chemical O-Glycosylations: An Overview

Interaction of niobium and tantalum pentahalides with O-donors: coordination chemistry and activation reactions

Ferric sulfate hydrate-catalyzed O-glycosylation using glycals with or without microwave irradiation

Hg(OTf)2-catalyzed glycosylation using alkynoate as the leaving group

Niobium(V) chloride catalyzed microwave assisted synthesis of 2,3-unsaturated O-glycosides by the Ferrier reaction

Metabolic carbohydrate engineering by exogenously added monosaccharide supplement is a technique of importance for studying physiological role of various glycans. Additionally, it also has the potential of developing new drug molecules for specific targeting. Lack of a spectroscopic reporting moiety in carbohydrates makes understanding their biochemical and physiological role very difficult. Towards this goal, we have modified glucose, with a propargyl group, wherein an azido coumarinyl profluorophore has been linked by “click chemistry.” Here, we demonstrate the uptake and incorporation of this modified monosaccharide into bacteria, yeast and mammalian cells. We show that modification at C-2 (carbon numbered 2, according to IUPAC) position is tolerated best, and uptake is only slightly lower compared to glucose. In the presence of C-2-modified glucose, growth kinetics and cellular viability were also minimally affected in all the cell types used. Fluorescence spectroscopy of the labeled biomolecule and fluorescence imaging of the cells demonstrate that C-2-modified glucose is metabolically incorporated not only in the cell membrane but also accumulates in the nucleus. Such a fluorophore, incorporated into biomolecules, can be used as a tool to understand their structure–function relationship. Here, we show that the incorporation of such a fluorophore in a carbohydrate moiety may enable studying the physiological and biochemical processes associated with membranes.

Engineered glucose to generate a spectroscopic probe for studying carbohydrate biology.

Diversity Oriented Synthesis of Tricyclic Compounds from Glycals Using the Ferrier and the Pauson—Khand Reactions.

NbCl 5 catalyzes the Ferrier reaction of per- O -acetylated glycals with primary, secondary, allylic, benzylic and monosaccharide alcohols to give 2,3-unsaturated α-glycosides in short reaction times under microwave irradiation conditions.

Ashish Tripathi

Papers

Niobium(V) chloride catalyzed microwave assisted synthesis of 2,3-unsaturated O-glycosides by the Ferrier reaction

Engineered glucose to generate a spectroscopic probe for studying carbohydrate biology.

Diversity Oriented Synthesis of Tricyclic Compounds from Glycals Using the Ferrier and the Pauson—Khand Reactions.

Niobium(V) Chloride Catalyzed Microwave‐Assisted Synthesis of 2,3‐Unsaturated O‐Glycosides by the Ferrier Reaction.