Synthesis of 1,4-Cyclohexadiene Carboxylates through a Formal [2+4]-Cycloaddition of Propiolates under Cobalt Catalysis |
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| Authors: | Julie Charpentier Francis Voirol Felix Flachsmann Silvia Tanner Natalie Aeberli Gerhard Brunner Andreas Goeke |
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| Affiliation: | Givaudan Schweiz AG, Fragrances S&T, Ingredients Research, Kemptpark 50, CH-8310 Kemptthal, Switzerland |
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| Abstract: | A low-valent cobalt(I) complex, formed from the reduction of CoBr2(dppe) with zinc, acts as catalyst for the efficient [2+4] cycloaddition of β-alkyl, cycloalkyl and aryl substituted propiolates to dienes. This transformation yields synthetically relevant 1,4-cyclohexadiene carboxylates in good to excellent yields. Furthermore, the target compounds are novel lead structures for the discovery of fragrance ingredients from the fruity, floral and spicy odor family. |
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| Keywords: | alkynes catalysis cobalt cycloaddition cyclohexadiene fragrance chemistry |
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