An efficient, and mild synthetic route for the preparation of functionalized volatile oxa-bicyclo[4.1.0]-hept-4-ene (29 compounds, 44–98% isolated yields) has been developed relying on the association of IPrAuCl with NaBArF. The remarkable selectivity was demonstrated on a 1 g and 25 g scale with low catalyst loadings. The synthetic utility of these low-molecular-weight enols was further demonstrated by the derivatization of some adducts and by the unprecedented olfactory evaluation of all bicyclic derivatives.

The synthesis of original structures for the fragrance industry bearing bicyclic scaffolds is described. To the best of our knowledge, these structures are not found in the fragrance industry neither from natural nor synthetic pathways. NHC gold type catalysts showed excellent activities leading to light bicyclic enol ethers. Several bicyclic adducts were prepared in good to excellent yields (18-99%). Evaluation of NHC-Au complexes allowed to reach a TOF of 300 h-1. The evaluation for the organoleptic properties of [4.1.0]-bicyclic ethers were compared with the unprecedented properties of the 1,6-enyne precursors. The evaluations of starting materials showed a great interest on these structures with various olfactive facets. In this study we depicted the similarity and differences between starting ethers and their cycloisomerized bicyclic counterparts.

Over the last century, the fragrance industry had relied on the synthetic chemists for the development of new odors, but also for the replacement of some known materials due to allergy or toxicity. Transition metal‐catalyzed transformations have allowed atom economy and synthetic efficiency for several transformations and they caught the attention of fragrance industrials. The metal‐catalyzed cyclization reactions have been particularly successful toward the synthesis of key skeletons. This review highlights the developments of selected hedonic materials according to transition metal‐catalyzed according to cycloisomerization reactions and related rearrangements.