The eight diastereoisomeric p-menthane-2,5-diols (1-8), the four diastereoisomeric p-menth-l-ene-3,6-diols (9-12), and the two (+ )-p-menthane-2,5-diones (13 and 14), which all have the same absolute configuration at the isopropyl group as (-)-a-phellandrene (15), have been prepared, characterized, and interrelated. Absolute configurations have been established for 1-14 by stereoselective chemical interconversions, including hydrogenation of diols 9-12, Jones oxidation of diols 1-6, lithium aluminum hydride reduction of diones 13 and 14, and displacements by formate and hydride ions on monotosylates of diol 4.