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Stereoselective glycosylations of 2-azido-2-deoxy-glucosides using intermediate sulfonium ions.

ABSTRACT: TMSOTf-promoted glycosylations of 2-azido-2-deoxy-glucosyl trichloroacetimidates provide excellent alpha-anomeric selectivities when performed at a relatively high reaction temperature in the presence of PhSEt or thiophene. NMR and computation studies have shown that these glycosylations proceed through an equatorial anomeric sulfonium ion, which upon displacement by a sugar alcohol provides an axial glycoside. Computational studies have indicated that steric factors determine the selective formation of the beta-anomeric sulfonium ion.

SUBMITTER: Park J

PROVIDER: S-EPMC2533432 | biostudies-literature | 2007 May

REPOSITORIES: biostudies-literature

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Stereoselective glycosylations of 2-azido-2-deoxy-glucosides using intermediate sulfonium ions.

Park Jin J Kawatkar Sameer S Kim Jin-Hwan JH Boons Geert-Jan GJ

Organic letters 20070414 10

TMSOTf-promoted glycosylations of 2-azido-2-deoxy-glucosyl trichloroacetimidates provide excellent alpha-anomeric selectivities when performed at a relatively high reaction temperature in the presence of PhSEt or thiophene. NMR and computation studies have shown that these glycosylations proceed through an equatorial anomeric sulfonium ion, which upon displacement by a sugar alcohol provides an axial glycoside. Computational studies have indicated that steric factors determine the selective form ...[more]

PMID: 17432867

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