Determination of the stereochemistry of the tetrahydropyran sesquineolignans morinols A and B.

The 7',8'-stereochemistry of the tetrahydropyran sesquineolignans morinols A and B was determined as threo via synthetic studies and by comparison of NMR data of 7',8'-threo-morinol and 7',8'-erythro-morinol. This study also confirmed that the biosynthetic process produces enantiomeric mixtures of morinols A and B. This was ascertained by comparing the specific rotations of synthesized morinols A and B with those of naturally occurring morinols A and B.