Regioselective Acetolysis of HighlyO-Benzylated Carbohydrates Promoted by Iodine or an Iodine/Silane Combined Reagent: Use of Isopropenyl Acetate as an Alternative to Acetic Anhydride

Selective acetolysis of primary benzyl groups in carbohydrate derivatives under the mild reaction condition

Selective acetolysis of the primary benzyloxy groups in a wide variety of carbohydrate derivatives was achieved in excellent yield using acetic anhydride and perchloric acid supported over silica (HClO₄-SiO₂) as a solid acid catalyst in a fast reaction condition without using any organic solvent. The reaction condition is significantly rapid and can be scaled up for its use in the multi-step oligosaccharide synthesis.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

A mild acetolysis procedure for the regioselective removal of isopropylidene in di-O-isopropylidene-protected pyranoside systems

A mild acetolysis method for the regioselective removal of isopropylidene group from di-O-isopropylidene-protected hexopyranosides is reported. O-Isopropylidene-protected intermediates play an important role in carbohydrate chemistry, as they are often found in commercially available furanosyl and pyranosyl materials, and some of them contain more than one O-isopropylidene groups. Methods that permit regioselective removal of O-isopropylidene groups are extremely valuable, as the number of steps in the total synthesis of complex oligosaccharides could be significantly decreased. Here we report that trifluoroacetic acid (TFA)/acetic anhydride (Ac₂O) can be used to regioselectively convert one of the two O-isopropylidene groups to vicinal di-O-acetates in the di-O-isopropylidene-protected galacto- and fructo-pyranosyl systems, and the reagent is compatible with some common functionalities such as sulfonate esters, bromide, azide etc.

Simple one-pot regioselective 6-O-phosphorylation of carbohydrates and trehalose desymmetrization

Biologically essential carbohydrate 6-phosphates, especially trehalose 6-phosphate, can be synthesized easily in excellent overall yields in 2 steps involving minimum protecting group manipulations. We can cleave the diphenylphosphate group for further synthetic objectives.

Glycosylation with N-acetyl glycosamine donors using catalytic iron(iii) triflate: from microwave batch chemistry to a scalable continuous-flow process

Efficient glycosylation reactions of peracetylated β-d-N-acetyl glycosamines are described using catalytic iron(iii) triflate under microwave conditions or in a continuous flow process.