Stereoselectivity in the Hydroboration of C4-C-Methylene Groups
Conditions for the hydroxylation of an exocyclic methylene group at C4 of a pyranoside ring via hydroboration have been examined with a view to determining the optimum procedure for obtaining the axially-oriented C4-CH 2 OH group. The regio- and stereochemical outcome of the reactions rely not only...
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Veröffentlicht in: | Journal of carbohydrate chemistry 1987-09, Vol.6 (3), p.479-493 |
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Hauptverfasser: | , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | Conditions for the hydroxylation of an exocyclic methylene group at C4 of a pyranoside ring via hydroboration have been examined with a view to determining the optimum procedure for obtaining the axially-oriented C4-CH
2
OH group. The regio- and stereochemical outcome of the reactions rely not only on the hydroborating reagent used, but, to a surprising degree, on the nature of the protecting group at the "remote" C6-OH. Silyl ethers are preferred because the only by-product formed is the tertiary alcohol, which can be recycled through dehydration to the starting alkene by treatment with thionyl chloride. |
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ISSN: | 0732-8303 1532-2327 |
DOI: | 10.1080/07328308708057935 |