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Synthesis 2004(15): 2505-2508  
DOI: 10.1055/s-2004-831206
PAPER
© Georg Thieme Verlag Stuttgart · New York

A Facile Synthesis of Armed and Disarmed Colitose Thioglycosides

Bart Ruttens, Pavol Kováč*
NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
Fax: +1(301)4020589; e-Mail: kpn@helix.nih.gov;
Further Information

Publication History

Received 26 May 2004
Publication Date:
02 September 2004 (online)

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Abstract

Ethyl 2,4-di-O-acetyl-3,6-dideoxy-1-thio-β-l-xylo-­hexopyranoside (10) and ethyl 2,4-di-O-benzyl-3,6-dideoxy-1-thio-β-l-xylo-hexopyranoside (12) were synthesized in 60% and 55% overall yield, respectively. Starting from α-l-fucose, sequential peracetylation, anomeric bromination, nucleophilic substitution of the anomeric bromide with NaSEt and deacetylation gave ethyl 1-thio-β-l-fucopyranoside (6). Acid catalyzed regioselective cleavage of the orthoester in ethyl 2-O-acetyl-3,4-O-(1-ethoxyethylidene)-1-thio-β-l-fucopyranoside, prepared from 6, yielded the corresponding 2,4-diacetate, which was deoxygenated at C-3 to provide the disarmed thioglycoside 10. Deacetylation of 10, followed by benzyl­ation, gave armed thioglycoside 12. Several intermediates did not require purification by chromatography.

Key words

α-l-fucose - deoxygenation - colitose-containing oligosaccharides - carbohydrates - bioorganic chemistry