Illustrated Glossary of Organic Chemistry

Tetrahydropyran (THP): A saturated heterocyclic ring containing five sp3 carbon atoms and one sp3 oxygen atom having the molecular structure shown below, or a molecule containing this moiety. Most frequently encountered in pyranose carbohydrates, or as an alcohol protecting group.

Molecular structure of tetrahydropyran.


The atoms forming the tetrahydropyran moiety of glucopyranose are shown in red.


cat. TsOH

abbreviated as

Unprotected alcohol


Alcohol protected as a THP acetal

An alcohol is protected as a THP acetal by reaction with dihydropyran and catalytic toluenesulfonic acid.