This review is the sequel to the 2000 report on the recent advances in the chemistry of odorants and it summarizes the developments in fragrance chemistry over the past 20 years. Following the olfactory spectrum set out in that report, trendsetting so‐called captive odorants (patent‐protected ingredients unavailable to the market) are presented according to the main odor families: “fruity”, “marine”, “green”, “floral”, “spicy”, “woody”, “amber”, and “musky”. The design of odorants, their chemical synthesis, and their use in modern perfumery are illustrated with prominent examples. Featured are new fruity odorants that provide signature in the top note, as well as precursor technology. In the green domain, focus is on leafy notes and green pear. New benzodioxepines and benzodioxoles have modernized the marine family and required a revision of the existing olfactophore models. The replacement of Lilial and Lyral kept the industry busy in the floral domain with a plethora of new “muguets”. There was continued activity in the domain of rose odorants, especially in the area of rose ketones. Biotechnology became significant, for example, with Clearwood and Ambrofix, and the principal odorants of vetiver oil in the woody family have been found. Fourth and fifth families of musk odorants were also discovered and populated. Thus, new avenues for further explorations into fragrance chemistry have been opened.
The isomeric ionones 1−3 are of both academic and commercial interest. Since their first preparation at the end of the 19th century they have been widely used as fragrances and as starting materials or building blocks in the synthesis of many relevant products. The regioselective and/or enantioselective preparation of ionones has therefore been investigated with growing interest over the last decades. In this Microreview, we summarize the syntheses of optically active α‐ and γ‐ionones (1, 3) and the epoxy and dihydro ionones 4−7. In addition, the olfactory properties of most of them are reported comprehensively.
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