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α‐ and β‐Glycosyl Sulfonium Ions: Generation and Reactivity |
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| Authors: | Toshiki Nokami Dr. Akito Shibuya Shino Manabe Dr. Yukishige Ito Dr. Jun‐ichi Yoshida Prof. Dr. |
| Affiliation: | 1. Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering Kyoto University, Nishikyo‐ku, Kyoto 615‐8510 (Japan), Fax: (+81)?75‐383‐2727;2. RIKEN (The Institute of Physical and Chemical Research), Hirosawa, Wako, Saitama 351‐0198 (Japan) |
| Abstract: | Low‐temperature electrochemical oxidation of thioglycosides gave glycosyl triflates from which glycosyl sulfonium ions were produced (see scheme). The latter were characterized by NMR spectroscopy and cold‐spray mass spectrometry as a mixture of α‐ and β‐isomers (45:55). The α‐glycosyl sulfonium ion exhibited higher reactivity than the β‐glycosyl sulfonium ion in the reaction with methanol, which gave a mixture of α‐ and β‐methyl glycosides (41:59).  |
| Keywords: | carbohydrates glycosylation NMR spectroscopy oxidation stereochemistry |