Methods for site-selective transformations of hydroxyl groups in carbohydrate derivatives are reviewed. The construction of oligosaccharides of defined connectivity hinges on such transformations, which are also needed for the preparation of modified or non-natural sugar derivatives, the installation of naturally occurring postglycosylation modifications, the selective labeling or conjugation of carbohydrate derivatives, and the preparation of therapeutic agents or research tools for glycobiology. The review begins with a discussion of intrinsic factors and processes that can influence selectivity in reactions of unprotected or partially protected carbohydrate derivatives, followed by a description of transformations that engage two OH groups in cyclic adducts (acetals, ketals, boronic esters, and related species). An overview of the various classes of site-selective transformations of OH groups in sugars is then provided: the reactions discussed include esterification, thiocarbonylation, alkylation, glycosylation, arylation, silylation, phosphorylation, sulfonylation, sulfation, and oxidation. Emphasis is placed on recently developed methods that employ reagent or catalyst control to achieve otherwise challenging transformations or site-selectivities.

Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives.

An attempt is made to survey and categorize selective protection and deprotection reactions, so that practicing chemists/biologists may be able to choose a method for the preparation of protected inositol derivatives, depending on their requirement. In addition to being useful for those who work with inositols, it is hoped that this review will help to widen the scope of using cyclitol derivatives for the synthesis of various classes of natural and unnatural compounds with interesting properties. Emphasis is given to the literature published between 1985 and the end of the year 2002, involving selective protection/deprotection of inositol hydroxyl groups.

Regioselective protection and deprotection of inositol hydroxyl groups.

Cell signaling via inositol phosphates, in particular via the second messenger myo-inositol 1,4,5-trisphosphate, and phosphoinositides comprises a huge field of biology. Of the nine 1,2,3,4,5,6-cyclohexanehexol isomers, myo-inositol is pre-eminent, with "other" inositols (cis-, epi-, allo-, muco-, neo-, L-chiro-, D-chiro-, and scyllo-) and derivatives rarer or thought not to exist in nature. However, neo- and d-chiro-inositol hexakisphosphates were recently revealed in both terrestrial and aquatic ecosystems, thus highlighting the paucity of knowledge of the origins and potential biological functions of such stereoisomers, a prevalent group of environmental organic phosphates, and their parent inositols. Some "other" inositols are medically relevant, for example, scyllo-inositol (neurodegenerative diseases) and d-chiro-inositol (diabetes). It is timely to consider exploration of the roles and applications of the "other" isomers and their derivatives, likely by exploiting techniques now well developed for the myo series.

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The "Other" Inositols and Their Phosphates: Synthesis, Biology, and Medicine (with Recent Advances in myo-Inositol Chemistry).

Mycothiol: synthesis, biosynthesis and biological functions of the major low molecular weight thiol in actinomycetes

Protection for the Hydroxyl Group, Including 1,2‐ and 1,3‐Diols

Convenient synthesis of 4,6-di-O-benzyl-myo-inositol and myo-inositol 1,3,5-orthoesters

(±)-2,4-Di-O-benzoyl-myo-inositol 1,3,5-orthoformate, on heating in the presence of a base, undergoes transesterification to give 2,4,6-tri-O-benzoyl-myo-inositol 1,3,5-orthoformate and 2-O-benzoyl...

Reactivity controlled by lattice interactions in crystal: intermolecular acyl transfer in (±)-2,4-di-O-benzoyl-myo-inositol 1,3,5-orthoformate

Sulfonate protecting groups. Regioselective sulfonylation of myo-inositol orthoesters-improved synthesis of precursors of D- and L-myo-inositol 1,3,4,5-tetrakisphosphate, myo-inositol 1,3,4,5,6-pentakisphosphate and related derivatives.

Mechanism of silver (I) oxide mediated O-alkylation of 2,4-di-O-acyl-myo-inositol 1,3,5-orthoformates: effect of solvent and silver halide on the nature of the intermediates involved

Thoniyot Praveen

Papers

Regioselective protection and deprotection of inositol hydroxyl groups.

Convenient synthesis of 4,6-di-O-benzyl-myo-inositol and myo-inositol 1,3,5-orthoesters

Reactivity controlled by lattice interactions in crystal: intermolecular acyl transfer in (±)-2,4-di-O-benzoyl-myo-inositol 1,3,5-orthoformate

Sulfonate protecting groups. Regioselective sulfonylation of myo-inositol orthoesters-improved synthesis of precursors of D- and L-myo-inositol 1,3,4,5-tetrakisphosphate, myo-inositol 1,3,4,5,6-pentakisphosphate and related derivatives.

Mechanism of silver (I) oxide mediated O-alkylation of 2,4-di-O-acyl-myo-inositol 1,3,5-orthoformates: effect of solvent and silver halide on the nature of the intermediates involved