Dehydrogenation of ocimene by active carbon: artefact formation during headspace sampling from leaves of Phaseolus lunatus

The blend of volatiles emitted from jasmonate-treated Lima bean ( Phaseolus lunatus) leaves comprised two ocimene-derived artefacts that were only present, if the compounds were collected on active carbon traps. Identified were (3E, 5E)-2,6-dimethyl-3,5,7-octatrien-2-ol ( 6) and ( 3E, 5E)-2,6-dimethyl- 1,3,5,7-octatetraene ( 5) resulting from oxidation of ocimene ( 2) by active carbon in presence of humid air. The catalytical capacity of the active carbon could be exploited for a rapid and efficient functionalization of ocimene to give the ( 3E, 5E)-2-alkoxy3,5,7-octatrienes ( 14), ( 15), and ( 16) in methanol, ethanol, or isopropanol as solvents.