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A Highly Efficient and Stereocontrolled Synthesis of 2‐Deoxy‐1,5‐thioanhydro‐ L ‐hexitols from D ‐Glycals in a Tandem Nucleophilic Displacement Reaction
Author(s) -
Passacantilli Pietro,
Centore Clara,
Ciliberti Elena,
Leonelli Francesca,
Piancatelli Giovanni
Publication year - 2006
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200600010
Subject(s) - chemistry , glucal , glycosyl , sodium borohydride , nucleophile , glycosyl donor , stereochemistry , glycosylation , carbohydrate chemistry , total synthesis , organic chemistry , catalysis , biochemistry
2‐Deoxy‐1,5‐thioanhydro‐ L ‐hexitols have been synthesized in a concise sequence that includes: i) ring opening of glycals with aqueous mercury( II ) acetate/sodium borohydride; ii) mesylation of the free hydroxy groups of the multifunctionalized open intermediates; and iii) S‐heterocyclization by treatment with sodium sulfide. The thiosugar derivatives are obtained with a 60–80 % yield. Thus, D ‐glucal and D ‐galactal can be converted into the corresponding 2‐deoxy‐1,5‐thioanhydro‐ L ‐hexitols, while L ‐rhamnal gives 3,4‐di‐ O ‐benzyl‐2,6‐dideoxy‐1,5‐thioanhydro‐ D ‐ xylo ‐hexitol. This straightforward chemistry is shown to be useful for the synthesis of glycosyl derivatives of 2‐deoxy‐1,5‐thioanhydro‐ L ‐hexitol, starting from glycosyl glycals such as D ‐lactal, D ‐cellobial, D ‐maltal, D ‐melibial and D ‐gentiobial, thus avoiding the usually lengthy glycosylation procedures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)