Lilac aldehydes were first isolated from the lilac flower oil (Wakayama & Namba 1974) and later identified as fragrant components in Gardenia flowers (Hattori et al. 1978), in Platanthera stricta (Patt et al. 1988), and in Artemisia pallens (Misra et al. 1991). Lilac aldehydes are an important class of fragrance and flavor compounds in perfumery and ecology, (Wakayama & Namba 1974; Winterhalter et al. 1986). 

It is known that lilac aldehydes play an important role in the attraction of Lepidoptera (butterflies and moths) to flowers. Lilac compounds are known to attract noctuid moths alone, or together with other compounds, and are known as effective antennal stimulants in electroantennographic detections (Plepys et al., 2002; Dötterl 2004). Responses of Autographa gamma to a mixture of lilac aldehyde isomers were similar as to a mixture of in total 9 attractive compounds (including lilac aldehydes), and the lilac aldehydes elicited significantly more responses than any other compound tested (Plepys et al., 2002b). The lilac aldehydes were also proved to be the most attractive compounds for H. bicruris, the nursery pollinator of S. latifolia (Dötterl 2004).

However, it is not known if the single enantiomers differ in their biological activity.

	(2r,2'r,5'r)-lilac aldehyde		(2r,2'r,5's)-lilac aldehyde
	(2r,2's,5'r)-lilac aldehyde		(2r,2's,5's)-lilac aldehyde
	(2s,2'r,5'r)-lilac aldehyde		(2s,2'r,5's)-lilac aldehyde
	(2s,2's,5'r)-lilac aldehyde		(2s,2's,5's)-lilac aldehyde

Hattori R, Murake S, Yochida T. (1978). Chemical composition of the absolute from gardenia flower. Agric. Biol. Chem., 42: 1351-6. 

Kreck, M. & A. Mosandl (2003). Synthesis, Structure Elucidation, and Olfactometric Analysis of Lilac Aldehyde and Lilac Alcohol Stereoisomers, Journal of Agricultural and Food Chemistry, J. Agric. Food Chem.  51: 2722-2726.

Misra LN, Chandra A. Thakur RS. (1991). Fragent components of oil from Artemisia pallens. Phytochemistry 30: 549-52.

Patt JM, Rhoades DF, Corkil JA. (1988). Analysis of the floral fragrance of Platanthera stricta. Phytochemistry 27: 91-5. 

Wakayama S, Namba S. (1974). Lilac aldehydes. Bull. Chem. Soc. Japan, 47: 1293-4.

Winterhalter P., Katzenberger D., Schreier P. (1986) 6,7-Epoxy-linalool and related oxygenated terpenoids from Carica papaya fruit. Phytochemistry 25: 1347 1350.

_{Andreas Jürgens}