(4S,5S)-(-)-cis-Aerangis lactone - the sole stereoisomer of Aerangis lactone present in the scent of living, white flowering orchids (Aerangis confusa). The fragrance of the (4S,5S)-isomer was described by Bartschat, et. al., to be typical for the lactonic odour of A. confusa and A. kirkii, and identical to the olfactory qualities of natural Aerangis lactone. Odour threshold = 0.13 ng cis-Aerangis lactone (cis-4-methyl-5-decanolide) was described by Kaiser in 1993 as the main odour component of the African ‘moth orchids’ Aerangis confusa J. Stewart and Aerangis kirkii (Rolfe) Schltr. The cis isomer was found to have a very pleasant and surprising room-filling odor which on the one hand is reminiscent of certain aspects of the smell of the flower of the tuberose (Polianthes tuberosa) and gardenia varieties and on the other hand is reminiscent of caramel, condensed milk and coconut, especially coconut milk Also known as (4S,5S)-(-)-cis-4-methyl-5-decanolide or (5S,6S)-(-)-cis-6-pentyl-5-methyltetrahydropyran-2-one Ref: Bartschat, D., Lehmann, D., Dietrich, A., Mosandl, A., Kaiser, R. (1995). Chiral compounds of essential oils XIX: 4-Methyl-5-decanolide: Chirospecific analysis, structure and properties of the stereoisomers. Phytochem. Anal., 6, 130-134; Kaiser, R. The Scent of Orchids, Olfactory and Chemical Investigations ; Editions Roche, F. Hoffmann La Roche:AG Basel, 1993; Kaiser, R. 5-methyl-6-pentyl-tetrahydro-.alpha.-pyrone and analogs, US Patent No. 5,248,792 (September 28, 1993); Elisabetta Brenna, Claudia Dei Negri, Claudio Fuganti and Stefano Serra, Baker’s yeast-mediated approach to (-)-cis- and (+)-trans-Aerangis lactones, Tetrahedron: Asymmetry 12 (2001) 1871–1879.; Elisabetta Brenna, Claudio Fuganti and Stefano Serra, "Enantioselective perception of chiral odorants", Tetrahedron Asymmetry, 14 (1), 1–42, 2003; Wu, Y.; Shen, X.; Tang, C.-J.; Chen, Z.-L.; Hu, Q.; Shi, W.; Synthesis of Natural Fragrant Molecules cis-3-Methyl-4-decanolide and Aerangis Lactone. General Enantioselective Routes to beta-gamma-cis-Disubstituted gamma-Lactones and gamma-delta-cis-Disubstituted delta-Lactones, J. Org. Chem., 2002, 67(11) 3802-3810.

(4R,5R)-(+)-cis-Aerangis lactone - reminiscent of delta-decalactone and coconut, and with a fragrance intensity much lower than the (4S,5S)-isomer Odour threshold = 30 ng Also known as (4R,5R)-(+)-cis-4-methyl-5-decanolide or (5R,6R)-(+)-cis-6-pentyl-5-methyltetrahydropyran-2-one Ref: Bartschat, D., Lehmann, D., Dietrich, A., Mosandl, A., Kaiser, R. (1995). Chiral compounds of essential oils XIX: 4-Methyl-5-decanolide: Chirospecific analysis, structure and properties of the stereoisomers. Phytochem. Anal., 6, 130-134; Elisabetta Brenna, Claudio Fuganti and Stefano Serra, "Enantioselective perception of chiral odorants", Tetrahedron Asymmetry, 14 (1), 1–42, 2003

Ionones, Irones, Damascones & Structurally Related Odorants

Acyclics (Alcohols, Esters, Acids, Aldehydes)

Lactones

Sesquiterpenoid Related Odorants