Synthesis of the fragrance terpene epoxides and selective monocyclization promoted by camphor and oxone

A high level of regio‐selectivity in the epoxidation of monoterpenes with camphor and oxone® at pH 7 has been observed. This methodology when applied to acyclic terpenes such as citronellyl acetate, geranyl acetate yielded mainly chiral 6(S),7‐epoxides. Similarly, farnesyl acetate yielded 10(S),11‐epoxide. Alternatively, unsaturated monocyclic terpene alcohol such as (‐)‐α‐terpineol, 6‐methyl‐hept‐5‐en‐2‐ol, when treated with camphor and oxone® at pH ~4‐5 led to one‐pot oxidative‐cyclization to yield (‐)‐trans‐2‐(S)‐hydroxy‐1,8‐cineole and (+)‐2,2,6‐trimethyl‐tetrahydropyran‐3‐ol respectively. In addition, the epoxides, trans‐2‐hydroxyl‐cineole and its acetate synthesized herein have good perfumery value with woody and sweet aromas. Copyright © 2016 John Wiley & Sons, Ltd. A high level of stereo‐selectivity in the epoxidation of monoterpenes with camphor and oxone® at pH 7 has been observed. This methodology when applied to acyclic terpenes such as citronellol, citronellyl acetate, geranyl acetate yielded mainly chiral 6(S),7‐epoxides. Similarly farnesyl acetate yielded 10(S),11‐epoxide. Alternatively, (‐)‐α‐terpineol, when treated with camphor and oxone® at pH ~4‐5 led to one‐pot oxidative‐cyclization. In addition, the epoxides, trans‐2‐hydroxyl‐cineole and its acetate synthesized herein have good perfumery value with woody and sweet aromas.