Selective Tetrahydropyranylation under Non-Acidic Conditions

Rabah Azzouz; Laurent Bischoff; Marc-Henri Fouquet; Francis Marsais

doi:10.1055/s-2005-918916

LETTER

Selective Tetrahydropyranylation under Non-Acidic Conditions

Rabah Azzouz^a, Laurent Bischoff*^a, Marc-Henri Fouquet^b, Francis Marsais^a
^a Laboratoire de Chimie Organique Fine et Hétérocyclique, IRCOF-INSA Rouen, B.P. 08, 76131 Mont-Saint-Aignan, France
^b I.U.T. Rouen, Rue Lavoisier, 76821 Mont-Saint-Aignan, France
Fax: +33(2)35522962; e-Mail: laurent.bischoff@insa-rouen.fr;

Abstract

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Abstract

We report that the tetrahydropyranylation of hydroxyl groups, exhibiting especially very low nucleophilicities, can be achieved by means of Mitsunobu reaction with 2-hydroxytetrahydropyran. This reaction led to the protection of phenols and pyridinols without the use of an acidic catalyst. For instance hydroxypyridines could not be protected by dihydropyran under acidic conditions, whereas they underwent a smooth tetrahydropyranylation under Mitsunobu conditions. The method is selective for a phenol over an alcohol.

Key words

protecting groups - glycosylations - acetals - phenols - pyridines

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References

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