Synthesis of vinyl sulfoxide-modified pent-2-enofuranosides and hex-2-enopyranosides and preliminary studies of their reactivity

Abstract

Vinyl sulfoxide-modified pent-2-enofuranosides and hex-2-enopyranosides have been synthesized by using a controlled oxidation of C-3-deoxy-C-3-thioaryl furanosides and pyranosides, respectively, followed by mesylation of the C-2-hydroxyl group and elimination. In the furanose system, both diastereomers were formed in almost equal ratio, whereas the pyranose ring imposed diastereoselectivity of oxidation of the sulfur atom to produce only S s isomers in good overall yields. Vinyl sulfoxide-modified 2-enofuranosides were treated with NaCH 2NO 2 to obtain C-2 branched chain sugars. Furanosyl sulfoxides yielded products that were similar to the adducts obtained by treatment of the corresponding sulfones with nitromethane. The sulfinyl group in thepyranosides influenced the diastereoselectivity of addition to produce adducts that differed from the products obtained from the corresponding vinyl sulfones under similar reaction conditions. Oxidation of furanosyl sulfides to sulfoxides afforded both diastereomers. The chirality of the sulfoxide group did not greatly influence the addition patterns of vinyl sulfoxide-modified pent-2-enofuranosides. Oxidation of pyranosyl sulfide gave only one diastereomer and the modified hex-2-enopyranosides significantly influenced the outcome of carbon nucleophile addition to these Michael acceptors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.