Important chiral monoterpenoid ethers in flavours and essential oils - enantioselective analysis and biogenesis

The enantioselective analysis and the biogenesis of rose oxide, rose oxide ketone, nerol oxide, furanoid linalooloxide, pyranoid linalooloxide, dill e ther, linden ether, menthofuran, and 3,6-dimethylcoumaran is reviewed. All these compounds are important chiral cyclic monoterpenoid ethers and can be analyzed enantioselectively using modified cyclodextrins as chiral station ary phases in capillary gas chromatography (cGC). The evaluation of the ena ntiomeric ratios of these compounds can be used in the authenticity control of flavors and fragrances. Moreover, the enantioselective cGC is also an e fficient tool in elucidating the biogenesis of these compounds. Biomimetic studies as well as in vivo feeding experiments using stable isotope labelli ng have shown that polyhydroxylated or epoxidated monoterpenes are direct p recursors of these cyclic ethers.