Reduction of cis- and trans-1,2-epithio-p-menth-8-ene: preparation of new fragrant terpenoid thiols

The synthesis of 2‐mercapto‐p‐menth‐8‐ene (3) and 1‐mercapto‐p‐menth‐8‐ene (4) are described, starting, respectively, from thioepoxydation of (+)‐trans‐limonene 1,2‐epoxide (1a) and (+)‐cis‐limonene 1,2‐epoxide (1b) via hydride reduction of episulphides 2a and 2b. Structural determination of these sulphur‐containing terpenoids was achieved by one‐ and two‐dimensional NMR spectroscopy. The odours of these two new monoterpene thiols were described, respectively, as reminescent of grapefruit juice and as being typically alliaceous. Copyright © 2002 John Wiley & Sons, Ltd.