Author, as appears in the article.: M. Isabel Matheu Andrea Kövér Omar Boutureira Yolanda Díaz Sergio Castillón
Department: Química Analítica i Química Orgànica
URV's Author/s: MATHEU MALPARTIDA, MARÍA ISABEL Andrea Kövér Omar Boutureira Yolanda Díaz Sergio Castillón
Keywords: deoxycarbohydrates
Abstract: The preparation of challenging 2-deoxy-2-iodo-β-D-allo precursors of 2-deoxy-β-D-ribo-hexopyranosyl units and other analogues is reported using a robust olefination−cyclization−glycosylation sequence. Here, we particularly focus on tuning the stereoelectronic properties of the alkenyl sulfides intermediates in order to improve the diastereoselectivity of the cyclization step and, hence, the efficiency of the overall transformation. Phosphine oxides with the general formula Ph2P(O)CH2SR (R = t- Bu, Cy, p-MeOPh, 2,6-di-ClPh, and 2,6-di-MePh) were easily synthesized and subsequently used in the olefination reaction with 2,3,5-tri-O-benzyl-D-ribose and -D-arabinose. The corresponding sugar-derived alkenyl sulfides were submitted to a 6-endo [I+]- induced cyclization, and the resulting 2-deoxy 2-iodohexopyranosyl-1-thioglycosides were used as glycosyl donors for the stereoselective synthesis of 2-deoxy-2-iodohexopyranosyl glycosides. Among the different S-groups studied, t-Bu derivative was the best performer for the synthesis of cholesteryl 2-deoxy-2-iodomannopyranosides, whereas for the synthesis of 2-deoxy-2- iodoallopyranosides none of the derivatives here studied proved superior to the phenyl analogue previously described. Glycosylation of cholesterol with different D-allo and D-manno derivatives produced 2-deoxy-2-iodoglycosides with stereoselectivities in the same order in each case, reinforcing the involvement of an oxocarbenium ion as the common intermediate of this crucial glycosylation step.
Research group: Síntesis Orgànica Estereoselectiva
Thematic Areas: Química Química Chemistry
licence for use: https://creativecommons.org/licenses/by/3.0/es/
ISSN: 0022-3263
Author identifier: 0000-0001-5216-9260 n/a 0000-0002-0768-8309 0000-0001-5567-8108 n/a
Record's date: 2015-04-16
Last page: 3068
Journal volume: 79
Papper version: info:eu-repo/semantics/acceptedVersion
Link to the original source: https://pubs.acs.org/doi/10.1021/jo5001912
Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
Article's DOI: 10.1021/jo5001912
Entity: Universitat Rovira i Virgili
Journal publication year: 2014
First page: 3060
Publication Type: Article Artículo Article