Reactivity switching and selective activation of C-1 or C-3 in 2,3-unsaturated thioglycosides

Mukherjee, Arunima and Jayaraman, Narayanaswamy (2011) Reactivity switching and selective activation of C-1 or C-3 in 2,3-unsaturated thioglycosides. In: Carbohydrate Research, 346 (12, SI). pp. 1569-1575.

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Abstract

Reactivity switching and selective activation of C-1 or C-3 in 2,3-unsaturated thioglycosides, namely, 2,3-dideoxy-1-thio-D-hex-2-enopyranosides are reported. The reactivity switching allowed activation of either C-1 or C-3, with the use of either N-iodosuccinimide (NIS)/triflic acid (TfOH) or TfOH alone. C-1 glycosylation with alcohol acceptors occurred in the presence of NIS/TfOH, without the acceptors reacting at C-3. On the other hand, reaction of 2,3-unsaturated thioglycosides with alcohols mediated by triflic acid led to transposition of C-1 ethylthio-moiety to C-3 intramolecularly, to form 3-ethylthio-glycals. Resulting glycals underwent glycosylation with alcohols to afford 3-ethylthio-2-deoxy glycosides. However, when thiol was used as an acceptor, only a stereoselective addition at C-3 resulted, so as to form C-1, C-3 dithio-substituted 2-deoxypyranosides. (C) 2011 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	Carbohydrate Research
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	2-Deoxy sugars;Glycals;Glycosylation;Thioglycosides
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	05 Aug 2011 08:27
Last Modified:	05 Aug 2011 08:27
URI:	http://eprints.iisc.ac.in/id/eprint/39724

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