(-)-Carveol

Atmospheric environment, 2005, 39(40):7715-7730.

Gas-phase ozonolysis of the monoterpenoids (S)-(+)-carvone, (R)-(−)-carvone, (−)-carveol, geraniol and citral.[Reference: WebLink]

Biogenic emissions of volatile organic compounds (VOCs) play a fundamental role in atmospheric chemistry. Vegetation is the most abundant natural source of VOCs, while terpenoids, as limonene, alpha and beta pinene and mircene, top the plants emission list.
METHODS AND RESULTS:
Much interest has been demonstrated in oxidation and photooxidation reactions of VOCs, particularly of monoterpenoids, owing to their diversity and to uncertainties regarding their mechanism of reaction. Quantification of primary carbonylic compounds, as well as of biradical reaction components, is highly relevant to the understanding of the major reactions. In this context, taking into account both structural factors and the fact that these compounds are found in the essential oils of plants typically found in Brazil and that they may be present in the atmosphere from emission by the plants, the monoterpenoids (S)-(+)-carvone, (R)-(-)-carvone, (-)-Carveol, geraniol and citral (a mixture of the isomers geranial and neral) were selected for this study. The ozonolysis reactions of the monoterpenoids were carried out under dark conditions for all experiments, due to their photochemical reactivity.
CONCLUSIONS:
The analysis of the results lets us propose a mechanism by which these reactions occur. The observed results of the ozonolysis of S and R carvone suggest that the stereochemistry of asymmetric carbon does not affect either in the yields of both formaldehyde and of OH radicals produced in the reaction, or in the reactivity of these compounds, for which the rate constants were in the scale of 10(-6) s(-1). We found that, in the (-)-Carveol's cis and trans mixture, even though the hydroxyl in the axial position-in the case of trans-.