First total synthesis of 6-epi-phomonol

NFSI mediated C3-ether oxidation of glycals for the synthesis of hex-3-enuloses

Hex-3-enuloses constitute a vital carbohydrate synthetic intermediate that provide access to wide range of chiral molecules through diverse derivatizations. Herein we report synthesis of these fascinating scaffolds by oxidation of C3-ether protections on glycals in presence of N-fluorobenzenesulfonimide (NFSI) under Cu(I) catalysed conditions. Benzyl, methyl and silyl ethers have been efficiently oxidized to the carbonyl group. The oxidation has been found to be highly regioselective where an array of protecting groups were tolerant to the reaction conditions. Pyranosyl glycals from various commercially available sugars have been studied in this work to evaluate the broad substrate scope.

Versatile applications of 3-OxoGlycals: A review

3-Oxoglycals are versatile building blocks with extensive applications in glycochemistry, organic, and bio-organic sciences. They serve as powerful synthons, enabling the development of diverse organic structures. This review highlights the utility of easily obtainable 3-oxoglycals as fundamental building blocks for synthesizing various compounds, including rare sugars, N-inserted compounds, fused heterocycles, medium ring compounds, polycyclic molecules, cycloadducts, and axially chiral molecules. Some of these compounds exhibit significant biological activities, while others possess valuable photophysical properties. The simplicity of these reactions, using readily available starting materials under favorable conditions, makes 3-oxoglycals a valuable tool for creating novel molecules, benefiting the scientific community in various fields.

Synthesis of Hexenuloses and a Library of Disaccharides Possessing 3-oxo-glycal Unit

An expeditious method for the synthesis of monosaccharides and disaccharides possessing 3-oxo-glycal units is revealed. Several monosaccharides and disaccharide-derived glycals are converted to the corresponding hexenuloses in three steps involving halo-alkoxylation, dehydrohalogenation, and ketalyzation reactions. A number of 3-oxo-glycals are synthesized to show the methodology's importance and generality. Further, the protocol is successfully applied to synthesize a rare-sugar disaccharide donor unit present as part of the trisaccharide moiety in the reported natural product, versipelostatin.

Versatility of glycals in synthetic organic chemistry: coupling reactions, diversity oriented synthesis and natural product synthesis

Glycals, 1,2-unsaturated sugar derivatives, are versatile starting materials for the synthesis of natural products and the generation of novel structural features in Diversity Oriented Synthesis (DOS). The versatility of glycals in synthesis emanates, among others, from the presence of the ring oxygen and the enol-ether type unsaturation, the different types of stable conformations they can adopt depending on the nature of the protecting groups present and the ease with which the protecting groups of the three hydroxy groups could be tailored to suite for a desired manipulation. This review summarizes the literature on the different transformations of the endo glycals into biologically relevant compounds such as chromans, thiochromans, chromenes, thiochromenes, peptidomimetics, bridged benzopyrans etc., as well as on the use of glycals as chiral building blocks for the synthesis of various natural products such as aspicilin, reblastatin, diospongins, decytospolides, osmundalactones, paclitaxel, isatisine, d-fagomine, and spliceostatin, reported post 2014.

TEMPO-Catalyzed Oxidation of 3- O-Benzylated/Silylated Glycals to the Corresponding Enones Using a PIFA-Water Reagent System

A simple, highly efficient and regiospecific method for the direct conversion of 3- O-benzylated as well as silylated glycals into the corresponding enones has been developed using PIFA-TEMPO and water reagent system. The reaction is scalable on a gram scale under mild conditions with a yield up to 86%.