Chemistry Around Pinene and Pinane: A Facile Synthesis of Cyclobutanes and Oxatricyclo‐Derivative of Pinane from cis‐ and trans‐Pinanols

Abstract

Alpha-pinene and beta-pinene are abundantly represented in nature; they are obtained from renewable sources and are irreplaceable synthons for commercial-scale production of other terpenes. In a well-known process practiced by Millennium Specialty Chemicals (MSC), hydrogenation of pinenes gives cis- and trans-pinanes, which are oxidized to hydroperoxides, whose reduction gives cis- and trans-pinanols, respectively. Pyrolysis of the pinanols gives linalool. Industrial availability of the pinanols makes them attractive objects for further synthetic research. We found that, in a very simple process of 'chlorooxidation', cis- and trans-pinanols react with hypochloric acid producing a novel chloroketone 1-[3-(2-chloroethyl)-2,2-dimethylcyclobutyl]ethanone and a tricyclic ether 6,9-dimethyl-7-oxatricyclo[4.3.0.0(3,9)]nonane, respectively. Both compounds offer new broad synthetic opportunities, providing access to numerous dimethylcyclobutane derivatives and to C(9)-functionalized pinenes and pinanes. The chlorooxidation reaction was also extended to other terpene alcohols such as dihydroplinol, tetrahydromyrcenol, and tetrahydrolinalool. This review, based on a presentation at the RSC/SCI conference Flavours & Fragrances 2007 in London, September 24-26, 2007, will touch on environmental issues related to pinenes, give a brief overview of the existing pinene-based technologies, and discuss the new experimental results.

Kinetic study of the thermal rearrangement of cis- and trans-2-pinanol

“…The main undesired side-products of this thermal rearrangement is plinol [11]. Besides plinol, Ohloff and Klein [9] identified ␤-terpineol (<3%) and a methyl-ketone (<5%) as byproducts of the pyrolysis of cis-and trans-2-pinanol at 873 K. The structure of the methyl-ketone was later elucidated as 5,7-dimethyloct-6-ene-2-one by Coxon et al [12], Erman and Kane [13] reported isolinalool as a minor product during the pyrolysis of pinanols. Chemical structures of the aforementioned compounds are depicted in Fig.…”

Therapeutic Potential of α- and β-Pinene: A Miracle Gift of Nature

“…have shown promising results in this regard. Pinenes have bicyclo [3.1.1] heptene or -heptane C-skeletons; thus, they take part in rearrangement and ring-opening reactions, producing different derivatives [4].…”

Bioconversion of essential oil components of Perilla frutescens by Saccharomyces cerevisiae

“…Monoterpenes are also used as flavors and fragrances because they typically have pleasant aroma and volatilize at room temperature. Furthermore, compounds such as camphor and α-terpineol are synthesized by chemical conversion (9) or biotransformation by microorganisms (10,11) from monoterpene compounds such as α-pinene that are abundant in nature and inexpensively available as a raw material. Bioconversion by microorganisms rather than chemical conversion for the synthesis of compounds is advantageous because the reaction can be performed under mild conditions, multiple reactions can be performed in one step, and bioconversion often provides high stereo-and regiospecificity.…”