Stereochemical Studies of Monoterpene Compounds. I. The Conformation of (+)-p-Menthane-3,4-diol Obtained by the Performic Acid Oxidation of (+)-p-Menth-3-ene

The conformational analysis of (+)-p-menthane-3,4-diol, which had been obtained by the hydroxylation of (+)-p-menth-3-ene with performic acid in the presence of water, has been performed mainly by means of infrared spectra. It has been shown that the two hydroxyl groups at the C3- and C4-positions take a diaxial conformation, that they are, accordingly, trans to each other, and that the methyl group presumably holds an equatorial orientation. It has also been found that p-menthane-trans(diaxial)-2,3-diol results from the p-menth-2-ene coexisting in the sample of p-menth-3-ene. A stereochemical course of the hydroxylation reaction has been discussed.