Internal asymmetric induction by the C-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides

Since the enantio or diastereoselective preparation of sulfoxides is a current challenge, we explore the possibility of inducing diastereoselectivity in the oxidation of the sulfur atom of thiodisaccharides, according to their substitution patterns. Thus, a series of 3-deoxy-4-S-(β-d-glucopyranosyl)...

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Publicado:	2017
Materias:	Atoms Chemical shift Oxidation Stereoselectivity Sulfur Absolute configuration Anisotropic effects Asymmetric induction Diastereo-selectivity Diastereoselective Free hydroxyl groups Oxidation reactions Substitution patterns Internal oxidation
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20462069_v7_n70_p44410_Colomer http://hdl.handle.net/20.500.12110/paper_20462069_v7_n70_p44410_Colomer
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_20462069_v7_n70_p44410_Colomer
record_format	dspace
spelling	paper:paper_20462069_v7_n70_p44410_Colomer2023-06-08T16:33:46Z Internal asymmetric induction by the C-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides Atoms Chemical shift Oxidation Stereoselectivity Sulfur Absolute configuration Anisotropic effects Asymmetric induction Diastereo-selectivity Diastereoselective Free hydroxyl groups Oxidation reactions Substitution patterns Internal oxidation Since the enantio or diastereoselective preparation of sulfoxides is a current challenge, we explore the possibility of inducing diastereoselectivity in the oxidation of the sulfur atom of thiodisaccharides, according to their substitution patterns. Thus, a series of 3-deoxy-4-S-(β-d-glucopyranosyl)-4-thio-β-d-xylo-hexopyranoside derivatives, with different substituents at C-6 (OH, OAc or OTBS) of the reducing end, have been synthesized and treated with m-CPBA for the oxidation of the sulfur atom at C-4, which is vicinal to C-6. The absolute configuration at the sulfur stereocenter of the resulting sulfoxides was established taking into account shielding/deshielding anisotropic effects of the SO bond on the chemical shift of the NMR signals of selected protons, in the most populated syn φ/syn ψ conformation of the thiodisaccharide S-oxides. The OAc and OTBS derivatives afforded diastereomeric mixtures of R and S sulfoxides in a similar ratio (1.4 : 1 and 1.6 : 1, respectively). In contrast, the oxidation of thiodisaccharide with a free hydroxyl group at C-6 was completely diastereoselective in favor of the R sulfoxide. The influence of the thiodisaccharide C-6 substituent on the stereochemical course of the oxidation is discussed. © 2017 The Royal Society of Chemistry. 2017 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20462069_v7_n70_p44410_Colomer http://hdl.handle.net/20.500.12110/paper_20462069_v7_n70_p44410_Colomer
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Atoms Chemical shift Oxidation Stereoselectivity Sulfur Absolute configuration Anisotropic effects Asymmetric induction Diastereo-selectivity Diastereoselective Free hydroxyl groups Oxidation reactions Substitution patterns Internal oxidation
spellingShingle	Atoms Chemical shift Oxidation Stereoselectivity Sulfur Absolute configuration Anisotropic effects Asymmetric induction Diastereo-selectivity Diastereoselective Free hydroxyl groups Oxidation reactions Substitution patterns Internal oxidation Internal asymmetric induction by the C-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides
topic_facet	Atoms Chemical shift Oxidation Stereoselectivity Sulfur Absolute configuration Anisotropic effects Asymmetric induction Diastereo-selectivity Diastereoselective Free hydroxyl groups Oxidation reactions Substitution patterns Internal oxidation
description	Since the enantio or diastereoselective preparation of sulfoxides is a current challenge, we explore the possibility of inducing diastereoselectivity in the oxidation of the sulfur atom of thiodisaccharides, according to their substitution patterns. Thus, a series of 3-deoxy-4-S-(β-d-glucopyranosyl)-4-thio-β-d-xylo-hexopyranoside derivatives, with different substituents at C-6 (OH, OAc or OTBS) of the reducing end, have been synthesized and treated with m-CPBA for the oxidation of the sulfur atom at C-4, which is vicinal to C-6. The absolute configuration at the sulfur stereocenter of the resulting sulfoxides was established taking into account shielding/deshielding anisotropic effects of the SO bond on the chemical shift of the NMR signals of selected protons, in the most populated syn φ/syn ψ conformation of the thiodisaccharide S-oxides. The OAc and OTBS derivatives afforded diastereomeric mixtures of R and S sulfoxides in a similar ratio (1.4 : 1 and 1.6 : 1, respectively). In contrast, the oxidation of thiodisaccharide with a free hydroxyl group at C-6 was completely diastereoselective in favor of the R sulfoxide. The influence of the thiodisaccharide C-6 substituent on the stereochemical course of the oxidation is discussed. © 2017 The Royal Society of Chemistry.
title	Internal asymmetric induction by the C-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides
title_short	Internal asymmetric induction by the C-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides
title_full	Internal asymmetric induction by the C-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides
title_fullStr	Internal asymmetric induction by the C-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides
title_full_unstemmed	Internal asymmetric induction by the C-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides
title_sort	internal asymmetric induction by the c-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides
publishDate	2017
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20462069_v7_n70_p44410_Colomer http://hdl.handle.net/20.500.12110/paper_20462069_v7_n70_p44410_Colomer
_version_	1768543774543183872

Internal asymmetric induction by the C-6 substituent on the oxidation reaction of interglycosidic sulfur atom of thiodisaccharides

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