Synthesis of All Eight L-Glycopyranosyl Donors Using CH Activation
The synthesis of all eight rare, but biologically important L‐hexoses as the according thioglycosyl donors was achieved through a procedure involving the CH activation of their corresponding 6‐deoxy‐L‐hexoses. The key steps of the procedure were the silylation of the OH group at C4 followed by an i...
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Veröffentlicht in: | Angewandte Chemie International Edition 2014-12, Vol.53 (50), p.13889-13893 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The synthesis of all eight rare, but biologically important L‐hexoses as the according thioglycosyl donors was achieved through a procedure involving the CH activation of their corresponding 6‐deoxy‐L‐hexoses. The key steps of the procedure were the silylation of the OH group at C4 followed by an intramolecular CH activation of the methyl group in γ‐position; both steps were catalyzed by iridium. The following Fleming–Tamao oxidation and acetylation gave the suitably protected L‐hexoses. This is the first general method for the preparation of all eight L‐hexoses as their thioglycosyl donors ready for glycosylation and the first example of an iridium‐catalyzed C(sp3)H activation on sulfide‐containing compounds.
A one‐pot four‐step procedure was developed for the synthesis of all eight L‐glycopyranosyl donors from the corresponding 6‐deoxy thioglycosides. Ir‐catalyzed silylation (a) and CH activation (b), followed by a Fleming–Tamao oxidation (c) and acetylation (d) led to highly functionalized thioglycosides. |
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ISSN: | 1433-7851 1521-3773 |
DOI: | 10.1002/anie.201408209 |