Ghosh KK, Uttry A, Mondal A, Ghiringhelli F, Wedi P, van Gemmeren M. Ligand-Enabled γ-C(sp
3 )-H Olefination of Free Carboxylic Acids.
Angew Chem Int Ed Engl 2020;
59:12848-12852. [PMID:
32250014 PMCID:
PMC7496353 DOI:
10.1002/anie.202002362]
[Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/01/2020] [Indexed: 01/15/2023]
Abstract
We report the ligand-enabled C-H activation/olefination of free carboxylic acids in the γ-position. Through an intramolecular Michael addition, δ-lactones are obtained as products. Two distinct ligand classes are identified that enable the challenging palladium-catalyzed activation of free carboxylic acids in the γ-position. The developed protocol features a wide range of acid substrates and olefin reaction partners and is shown to be applicable on a preparatively useful scale. Insights into the underlying reaction mechanism obtained through kinetic studies are reported.
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