The epoxidation of p-menth-1- and -3-ene

Oxidation of p-menth-3-ene with perbenzoic acid in benzene gives cis- and trans-3,4-epoxymenthane in the ratio ca. 3:2. A similar oxidation of p-menth-1-ene gives cis- and trans-epoxides in the ratio ca. 2:3. The trans-epoxides are more rapidly reduced than the cis-compounds when the mixtures are treated with lithium aluminium hydride; this has been explained in terms of the preferred conformations of the epoxides and the diaxial opening rule. The epoxides from p-menth-1-ene are reduced faster than those from p-menth-3-ene. The stereochemistry of the p-menthan-4-ols has been confirmed.